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  • 1. Chouhan, Dimple
    et al.
    Thatikonda, Naresh
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Nilebäck, Linnea
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Widhe, Mona
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Mandal, Biman B.
    Recombinant Spider Silk Functionalized Silkworm Silk Matrices as Potential Bioactive Wound Dressings and Skin Grafts2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 28, p. 23560-23572Article in journal (Refereed)
    Abstract [en]

    Silk is considered to be a potential biomaterial for a wide number of biomedical applications. Silk fibroin (SF) can be retrieved in sufficient quantities from the cocoons produced by silkworms. While it is easy to formulate into scaffolds with favorable mechanical properties, the natural SF does not contain bioactive functions. Spider silk proteins, on the contrary, can be produced in fusion with bioactive protein domains, but the recombinant procedures are expensive, and large-scale production is challenging. We combine the two types of silk to fabricate affordable, functional tissue-engineered constructs for wound-healing applications. Nanofibrous mats and microporous scaffolds made of natural silkworm SF are used as a bulk material that are top-coated with the recombinant spider silk protein (4RepCT) in fusion with a cell-binding motif, antimicrobial peptides, and a growth factor. For this, the inherent silk properties are utilized to form interactions between the two silk types by self-assembly. The intended function, that is, improved cell adhesion, antimicrobial activity, and growth factor stimulation, could be demonstrated for the obtained functionalized silk mats. As a skin prototype, SF scaffolds coated with functionalized silk are cocultured with multiple cell types to demonstrate formation of a bilayered tissue construct with a keratinized epidermal layer under in vitro conditions. The encouraging results support this strategy of fabrication of an affordable bioactive SF-spider silk-based biomaterial for wound dressings and skin substitutes.

  • 2.
    Gomez-Cid, L.
    et al.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Fuentes, L.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Fernandez-Santos, M. E.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Suarez-Sancho, S.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Plasencia, V.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Climent, A. M.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Sanz-Ruiz, R.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Atienza, F.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Aviles, F. F.
    Hosp GU Gregorio Maranon, Serv Cardiol, CIBERCV, Madrid, Spain..
    Effect of spider silk matrix on cardiac tissue regeneration of mesenchymal stem cells2018In: European Journal of Clinical Investigation, ISSN 0014-2972, E-ISSN 1365-2362, Vol. 48, p. 150-150Article in journal (Other academic)
  • 3.
    Guo, Weijin
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Gustafsson, Linnea
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Jansson, Ronnie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology. KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Formation of a thin-walled Spider Silk Tube on a Micromachined Scaffold2018In: Proceeding of 2018 IEEE 31st International Conference on Micro Electro Mechanical Systems (MEMS), Institute of Electrical and Electronics Engineers (IEEE), 2018, Vol. 2018, p. 83-85Conference paper (Refereed)
    Abstract [en]

    This paper reports on the first formation of a thin bio-functionalized spider silk tube, supported by an internal micromachined scaffold, in which both the inside and outside of the tube wall are freely accessible. The silk tube could potentially be used as an artificial blood vessel in an in vitro tissue scaffold, where endothelial cells and tissue cells can grow on both sides of the silk tube.

  • 4.
    Güler, Rezan
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Thatikonda, Naresh
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Ghani, Hawraa Ali
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Löfblom, John
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Artificial VEGFR2-Specific Growth Factors Demonstrate Agonistic Effects in Both Soluble Form and When Immobilized Via Spider SilkManuscript (preprint) (Other academic)
  • 5. Hu, Francis Jingxin
    et al.
    Lundqvist, Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Uhlén, Mathias
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Rockberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    SAMURAI (Solid-phase Assisted Mutagenesis by Uracil Restricted Ablation In vitro) for Antibody Affinity Maturation and Paratope MappingManuscript (preprint) (Other academic)
    Abstract [en]

    Mutagenesis libraries are essential for combinatorial protein engineering. Despite improve- ments in gene synthesis and directed mutagenesis, current methodologies still have limitations regarding the synthesis of intact antibody scFv genes and simultaneous diversification of all six CDRs. Here, we de- scribe the generation of mutagenesis libraries for antibody affinity maturation, using a cell-free solid-phase technique for annealing of single-strand mutagenic oligonucleotides. This procedure consists of PCR-based incorporation of uracil into a wild-type template, bead-based capture, and elution of single-strand DNA, and in vitro uracil excision enzyme based degradation of the template DNA. Our approach enabled rapid (8 hours) mutagenesis and automated cloning of 50 position specific alanine mutants for mapping of a scFv antibody paratope. We further exemplify our method by generating affinity maturation libraries with di- versity introduced in critical, nonessential, or all CDR positions randomly. Assessment with Illumina deep sequencing showed >99% functional diversity in two libraries and the ability to diversify all CDR positions simultaneously. Selections of the libraries with bacterial display and deep sequencing evaluation of the selection output showed that diversity introduced in non-essential positions allowed quicker enrichment of improved binders compared to the other two diversification strategies.

  • 6.
    Kanje, Sara
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Venskutonyte, Raminta
    Lund Univ, Expt Med Sci, Med Struct Biol, BMC C13, SE-22184 Lund, Sweden..
    Scheffel, Julia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Nilvebrant, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Lindkvist-Petersson, Karin
    Lund Univ, Expt Med Sci, Med Struct Biol, BMC C13, SE-22184 Lund, Sweden..
    Hobert, Sophia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Protein Engineering Allows for Mild Affinity-based Elution of Therapeutic Antibodies2018In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 430, no 18, p. 3427-3438Article in journal (Refereed)
    Abstract [en]

    Presented here is an engineered protein domain, based on Protein A, that displays a calcium-dependent binding to antibodies. This protein, Z(ca), is shown to efficiently function as an affinity ligand for mild purification of antibodies through elution with ethylenediaminetetraacetic acid. Antibodies are commonly used tools in the area of biological sciences and as therapeutics, and the most commonly used approach for antibody purification is based on Protein A using acidic elution. Although this affinity-based method is robust and efficient, the requirement for low pH elution can be detrimental to the protein being purified. By introducing a calcium-binding loop in the Protein A-derived Z domain, it has been re-engineered to provide efficient antibody purification under mild conditions. Through comprehensive analyses of the domain as well as the Z(ca)-Fc complex, the features of this domain are well understood. This novel protein domain provides a very valuable tool for effective and gentle antibody and Fc-fusion protein purification. 

  • 7.
    Lindbo, Sarah
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Generation and engineering of ABD-derived affinity proteins for clinical applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Proteins that specifically recognize and bind to other molecules or structures are important tools in industrial and medical applications. Binding proteins engineered from small stable scaffold proteins have been utilized for several purposes due to their favorable biophysical properties, tolerance to mutagenesis, efficient tissue penetration and ease of production. The 46 amino acid long albumin-binding domain (ABD) derived from the bacterial receptor Protein G is a promising scaffold that has been explored in this thesis. The scaffold was subjected to combinatorial protein engineering for generation of ABD-derived binding proteins with novel specificities. Furthermore, the medical potential of engineered ABD- derived affinity proteins (ADAPTs) was evaluated in a series of pre-clinical studies.

    In the first studies, ADAPTs suitability as tracers for radionuclide molecular imaging was evaluated. Factors influencing biodistribution and tumor targeting properties were assessed in mice models bearing HER2 positive xenografts. All tested ADAPT constructs demonstrated high and specific targeting of HER2-expressing tumor cells as well as fast clearance from circulation. The results also showed that the size and character of the N- terminus affected the biodistribution profile of ADAPTs. Moreover, the targeting properties of ADAPTs proved to be highly influenced by the residualizing properties of the attached radionuclide label. Taken together, the results provided the first evidence that tumor imaging can be performed using ADAPTs and the favorable pharmacokinetic profiles in the studied mice models suggest that the scaffold is a promising candidate for clinical applications.

    In the last study, a platform for generation of stable ABD-derived affinity proteins with novel binding specificities was established using a multi-step approach combining directed evolution and rational protein design. A broad combinatorial protein library with 20 randomized positions in ABD was designed and binders against three distinct targets were selected using phage display. Characterization of the selected binders provided information regarding optimal positions to randomize in a final library. In addition, the isolated binders were subjected to mutagenesis in certain surface exposed positions and mutations that provided increased stability were introduced into the original scaffold. Finally, a more focused combinatorial protein library consisting of 11 randomized positions was designed and constructed. The library was validated by selections against the same set of targets as for the first, broad library. The isolation of highly stable affinity ligands confirms that the library can be used for generation of diverse and stable affinity molecules.

  • 8.
    Lindbo, Sarah
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Garousi, Javad
    Uppsala university.
    Mitran, Bogdan
    Uppsala university.
    Vorobyeva, Anzhelika
    Uppsala university.
    Oroujeni, Maryam
    Uppsala university.
    Orlova, Anna
    Uppsala university.
    Hober, Sophia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Tolmachev, Vladimir
    Uppsala university.
    Optimized molecular design of ADAPT-based HER2-imaging probes labelled with 111In and 68Ga2018In: Molecular Pharmaceutics, ISSN 1543-8384, E-ISSN 1543-8392, Vol. 15, no 7, p. 2674-2683Article in journal (Refereed)
    Abstract [en]

    Radionuclide molecular imaging is a promising tool for visualization of cancer associated molecular abnormalities in vivo and stratification of patients for specific therapies. ADAPT is a new type of small engineered proteins based on the scaffold of an albumin binding domain of protein G. ADAPTs have been utilized to select and develop high affinity binders to different proteinaceous targets. ADAPT6 binds to human epidermal growth factor 2 (HER2) with low nanomolar affinity and can be used for its in vivo visualization. Molecular design of 111In-labeled anti-HER2 ADAPT has been optimized in several earlier studies. In this study, we made a direct comparison of two of the most promising variants, having either a DEAVDANS or a (HE)3DANS sequence at the N-terminus, conjugated with a maleimido derivative of DOTA to a GSSC amino acids sequence at the C-terminus. The variants (designated DOTA-C59-DEAVDANS-ADAPT6-GSSC and DOTA-C61-(HE)3DANS-ADAPT6-GSSC) were stably labeled with 111In for SPECT and 68Ga for PET. Biodistribution of labeled ADAPT variants was evaluated in nude mice bearing human tumor xenografts with different levels of HER2 expression. Both variants enabled clear discrimination between tumors with high and low levels of HER2 expression. 111In-labeled ADAPT6 derivatives provided higher tumor-to-organ ratios compared to 68Ga-labeled counterparts. The best performing variant was DOTA-C61-(HE)3DANS-ADAPT6-GSSC, which provided tumor-to-blood ratios of 208 ± 36 and 109 ± 17 at 3 h for 111In and 68Ga labels, respectively.

  • 9.
    Lindbo, Sarah
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Gunneriusson, Elin
    Affibody AB.
    Ekblad, Caroline
    Affibody AB.
    Fant, Gunilla
    Affibody AB.
    Hober, Sophia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Design, construction and characterization of an ABD-based library with improved stabilityManuscript (preprint) (Other academic)
    Abstract [en]

    Recombinant affinity proteins binding specifically to other molecules are important tools for many clinical and industrial applications. Small robust protein scaffolds have proven to be well suited as frameworks for generation of novel affinity binders due to their stability. Here we used the albumin-binding domain (ABD) of protein G from Streptococcus G148 as scaffold to design a new combinatorial library capable of generating stable binders to various target proteins with high affinity and specificity. To create a robust framework able to generate highly stable binders, mutations in the non-binding region were evaluated and residues providing increased stability were introduced into the scaffold. By combining rational design with combinatorial protein engineering we also evaluated the surface exposed amino acids at the albumin-binding interface and identified 11 residues suitable for randomization. The potency of the novel scaffold library was assessed by screening for binders using phage display against three distinct targets; complement factor 4, (C4), insulin and interleukin-6 (IL-6). Binders in the nanomolar range with melting temperature above 57°C were selected for all three targets. Notably, the identified IL-6 binders were characterized by extreme thermal stability with variants demonstrating organized structures even at 90°C. This demonstrates that stable binders with distinct specificities can be generated and thus proves the high potential of the library.

  • 10.
    Liu, Hao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Tumor targeted delivery of cytotoxic payloads using affibody molecules and ABD-derived affinity proteins2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cancer treatment cost billions of dollars every year, but the mortality rate is still high. An ideal treatment is the so-called “magic bullets” that recognize and kill tumor cells while leaving normal cells untouched. In recent years, some nonimmunoglobulin alternative scaffold affinity proteins, such as affibody molecules and ADAPTs, have emerged and been used to specifically recognize different tumor antigens. In this thesis, I studied the properties and anti-tumor activities of affibody and ADAPT fusion toxins and affibody drug conjugates. In the first two papers, I studied a panel of recombinant affitoxins (affibody toxin fusion proteins) consisting of an anti-HER2 affibody molecule (ZHER2), an albumin binding domain (ABD) and a truncated version of Pseudomonas Exotoxin A(PE38X8). The affitoxins demonstrated specific anti-tumor activity on HER2-overexpressing tumor cells in vitro. A biodistribution experiment showed that addition of an ABD increased the blood retention by 28-fold and a (HE)3 N-terminal purification tag decreased hepatic uptake of the affitoxin compared with a His6 tag. In paper III, I studied immunotoxins consisting of an anti-HER2 ABD-derived affinity protein (ADAPT), an ABD and a minimized and deimmunized version of Pseudomonas exotoxin A (PE25). These immunotoxins demonstrated potent and specific cytotoxicity toward HER2 overexpressing tumor cells in vitro similar to affitoxins. In paper IV, I produced a panel of affibody drug conjugates consisting of ZHER2, ABD and malemidocaproylmertansine (mc-DM1). The conjugates had selective toxic activity on HER2-overexpressing tumor cells in vitro comparable with the approved drug trastuzumab emtansine. The conjugate, ZHER2-ZHER2-ABD-mc-DM1 was found to prolong the life span of tumor bearing mice and delayed the growth ofxenografted SKOV-3 tumors. In conclusion, affibody molecules and ADAPTs are promising alternatives to antibodies for targeted tumor therapy.

  • 11.
    Lundqvist, Magnus
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Methods for cell line and protein engineering2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Therapeutic proteins are becoming increasingly important. They are desirable, as they typically possess low adverse effects and higher specificity compared to the traditional, small molecule drugs. But they are also more complex and involve different intricate and expensive development and production processes. Through new technologies in protein and cell line development, more efficient and safer drugs can be readily available and at a lower cost. This thesis gives an overview of how protein therapeutics are developed and produced. It explores strategies to improve the efficacy and safety of protein drugs and how to improve production yields. In the present investigation, two papers present new methods for high-throughput cloning and site-directed mutagenesis using solid-phase immobilization of DNA fragments. These methods were designed to generate new drug candidates with swiftness and ease. Three papers show the development of a new cell line screening system that combines droplet microfluidics and the split-GFP reporter system. This combination allows for relative quantification of secreted recombinant proteins between individual cells and provides a tool for the selection of the best-producing clones for final production from a heterologous cell pool. The final paper explores the possibility to produce proteins at a higher cell density by examining how the metabolome and proteome of a perfusion bioreactor evolve as the cell density reaches exceptionally high levels. The consistent goal of all of these studies is to expedite the development and improve the production of therapeutic proteins, to assist the discovery of new drugs and to bring down production and development costs. Engineered proteins can be used to cure previously incurable diseases or give current medications a higher efficacy. Lower production and development costs can make the treatments available to more people.

  • 12.
    Nilvebrant, Johan
    et al.
    KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Rockberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    An introduction to epitope mapping2018In: Methods in Molecular Biology, ISSN 1064-3745, E-ISSN 1940-6029, Vol. 1785, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Antibodies are protein molecules used routinely for therapeutic, diagnostic, and research purposes due to their exquisite ability to selectively recognize and bind a given antigen. The particular area of the antigen recognized by the antibody is called the epitope, and for proteinaceous antigens the epitope can be of complex nature. Information about the binding epitope of an antibody can provide important mechanistic insights and indicate for what applications an antibody might be useful. Therefore, a variety of epitope mapping techniques have been developed to localize such regions. Although the real picture is even more complex, epitopes in protein antigens are broadly grouped into linear or discontinuous epitopes depending on the positioning of the epitope residues in the antigen sequence and the requirement of structure. Specialized methods for mapping of the two different classes of epitopes, using high-throughput or high-resolution methods, have been developed. While different in their detail, all of the experimental methods rely on assessing the binding of the antibody to the antigen or a set of antigen mimics. Early approaches utilizing sets of truncated proteins, small numbers of synthesized peptides, and structural analyses of antibody-antigen complexes have been significantly refined. Current state-of-the-art methods involve combinations of mutational scanning, protein display, and high-throughput screening in conjunction with bioinformatic analyses of large datasets.

  • 13.
    Petrou, Georgia
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Jansson, Ronnie
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Engineering.
    Hogqvist, Mark
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Erlandsson, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Wågberg, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology.
    Hedhammar, My
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Crouzier, Thomas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Glycoscience.
    Genetically Engineered Mucoadhesive Spider Silk2018In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, no 8, p. 3268-3279Article in journal (Refereed)
    Abstract [en]

    Mucoadhesion is defined as the adhesion of a material to the mucus gel covering the mucous membranes. The mechanisms controlling mucoadhesion include nonspecific electrostatic interactions and specific interactions between the materials and the mucins, the heavily glycosylated proteins that form the mucus gel. Mucoadhesive materials can be used to develop mucosal wound dressings and noninvasive transmucosal drug delivery systems. Spider silk, which is strong, biocompatible, biodegradable, nontoxic, and lightweight would serve as an excellent base for the development of such materials. Here, we investigated two variants of the partial spider silk protein 4RepCT genetically engineered in order to functionalize them with mucoadhesive properties. The pLys-4RepCT variant was functionalized with six cationically charged lysines, aiming to provide nonspecific adhesion from electrostatic interactions with the anionically charged mucins, while the hGal3-4RepCT variant was genetically fused with the Human Galectin-3 Carbohydrate Recognition Domain which specifically binds the mucin glycans Gal beta 1-3GlcNAc and Gal beta 1-4GlcNAc. First, we demonstrated that coatings, fibers, meshes, and foams can be readily made from both silk variants. Measured by the adsorption of both bovine submaxillary mucin and pig gastric mucin, the newly produced silk materials showed enhanced mucin binding properties compared with materials of wild-type (4RepCT) silk. Moreover, we showed that pLys-4RepCT silk coatings bind mucins through electrostatic interactions, while hGal3-4RepCT silk coatings bind mucins through specific glycan-protein interactions. We envision that the two new mucoadhesive silk variants pLys-4RepCT and hGal3-4RepCT, alone or combined with other biofunctional silk proteins, constitute useful new building blocks for a range of silk protein-based materials for mucosal treatments.

  • 14. Summer, D.
    et al.
    Garousi, J.
    Oroujeni, M.
    Mitran, B.
    Andersson, Ken G.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Vorobyeva, A.
    Löfblom, John
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Orlova, A.
    Tolmachev, V.
    Decristoforo, C.
    Cyclic versus Noncyclic Chelating Scaffold for 89Zr-Labeled ZEGFR:2377 Affibody Bioconjugates Targeting Epidermal Growth Factor Receptor Overexpression2018In: Molecular Pharmaceutics, ISSN 1543-8384, E-ISSN 1543-8392, Vol. 15, no 1, p. 175-185Article in journal (Refereed)
    Abstract [en]

    Zirconium-89 is an emerging radionuclide for positron emission tomography (PET) especially for biomolecules with slow pharmacokinetics as due to its longer half-life, in comparison to fluorine-18 and gallium-68, imaging at late time points is feasible. Desferrioxamine B (DFO), a linear bifunctional chelator (BFC) is mostly used for this radionuclide so far but shows limitations regarding stability. Our group recently reported on fusarinine C (FSC) with similar zirconium-89 complexing properties but potentially higher stability related to its cyclic structure. This study was designed to compare FSC and DFO head-to-head as bifunctional chelators for 89Zr-radiolabeled EGFR-targeting ZEGFR:2377 affibody bioconjugates. FSC-ZEGFR:2377 and DFO-ZEGFR:2377 were evaluated regarding radiolabeling, in vitro stability, specificity, cell uptake, receptor affinity, biodistribution, and microPET-CT imaging. Both conjugates were efficiently labeled with zirconium-89 at room temperature but radiochemical yields increased substantially at elevated temperature, 85 °C. Both 89Zr-FSC-ZEGFR:2377 and 89Zr-DFO-ZEGFR:2377 revealed remarkable specificity, affinity and slow cell-line dependent internalization. Radiolabeling at 85 °C showed comparable results in A431 tumor xenografted mice with minor differences regarding blood clearance, tumor and liver uptake. In comparison 89Zr-DFO-ZEGFR:2377, radiolabeled at room temperature, showed a significant difference regarding tumor-to-organ ratios. MicroPET-CT imaging studies of 89Zr-FSC-ZEGFR:2377 as well as 89Zr-DFO-ZEGFR:2377 confirmed these findings. In summary we were able to show that FSC is a suitable alternative to DFO for radiolabeling of biomolecules with zirconium-89. Furthermore, our findings indicate that 89Zr-radiolabeling of DFO conjugates at higher temperature reduces off-chelate binding leading to significantly improved tumor-to-organ ratios and therefore enhancing image contrast.

  • 15.
    Syrén, Per-Olof
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Sci Life Lab, Dept Fibre & Polymer Technol, S-17165 Solna, Sweden.;KTH Royal Inst Technol, Dept Prot Sci, S-17165 Solna, Sweden..
    Enzymatic Hydrolysis of Tertiary Amide Bonds by anti Nucleophilic Attack and Protonation2018In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 83, no 21, p. 13543-13548Article in journal (Refereed)
    Abstract [en]

    The molecular mechanisms conferring high resistance of planar tertiary amide bonds to hydrolysis by most enzymes have remained elusive. To provide a chemical explanation to this unresolved puzzle, UB3LYP calculations were performed on an active site model of Xaa-Pro peptidases. The calculated reaction mechanism demonstrates that biocatalysts capable of tertiary amide bond hydrolysis capitalize on anti nucleophilic attack and protonation of the amide nitrogen, in contrast to the traditional syn displayed by amidases and proteases acting on secondary amide bonds.

  • 16.
    Volk, Anna-Luisa
    et al.
    KTH, School of Biotechnology (BIO).
    Rockberg, Johan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Discontinuous epitope mapping of antibodies using bacterial cell surface display of folded domains2018In: Epitope Mapping Protocols, Humana Press, 2018, p. 159-183Chapter in book (Refereed)
    Abstract [en]

    Knowledge of the exquisite-binding surface of an antibody on its target protein is of great value, in particular for therapeutic antibodies for understanding method of action and for stratification of patients carrying the necessary epitope for desired drug efficacy, but also for capture assays under native conditions. Several epitope mapping methodologies have been described for this purpose, with the laborious X-ray crystallography method being the ideal method for mapping of discontinuous epitopes in antibody-antigen crystal complexes and high-throughput peptide-based methods for mapping of linear epitopes. We here report on the usage of a bacterial surface display-based method for mapping of structural epitopes by display of folded domains on the surface of Gram positive bacteria, followed by domain-targeted mutagenesis and library analysis for the identification of key-residues by flow sorting and sequencing. Identified clones with reduced affinity are validated by single clone FACS and subsequent full-length expression in mammalian cells for validation.

  • 17.
    Wu, Yu-Tang
    et al.
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Qiu, Xue
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Lindbo, Sarah
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Susumu, Kimihiro
    US Naval Res Lab, Opt Sci Div, Code 5600, Washington, DC USA.;KeyW Corp, Hanover, MD 21076 USA..
    Medintz, Igor L.
    US Naval Res Lab, Ctr Bio Mol Sci & Engn, Code 6900, Washington, DC USA..
    Hober, Sophia
    KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Hildebrandt, Niko
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Quantum Dot-Based FRET Immunoassay for HER2 Using Ultrasmall Affinity Proteins2018In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 14, no 35, article id 1802266Article in journal (Refereed)
    Abstract [en]

    Engineered scaffold affinity proteins are used in many biological applications with the aim of replacing natural antibodies. Although their very small sizes are beneficial for multivalent nanoparticle conjugation and efficient Forster resonance energy transfer (FRET), the application of engineered affinity proteins in such nanobiosensing formats has been largely neglected. Here, it is shown that very small (approximate to 6.5 kDa) histidine-tagged albumin-binding domain-derived affinity proteins (ADAPTs) can efficiently self-assemble to zwitterionic ligand-coated quantum dots (QDs). These ADAPT-QD conjugates are significantly smaller than QD-conjugates based on IgG, Fab', or single-domain antibodies. Immediate applicability by the quantification of the human epidermal growth factor receptor 2 (HER2) in serum-containing samples using time-gated Tb-to-QD FRET detection on the clinical benchtop immunoassay analyzer KRYPTOR is demonstrated here. Limits of detection down to 40 x 10(-12)m (approximate to 8 ng mL(-1)) are in a relevant clinical concentration range and outperform previously tested assays with antibodies, antibody fragments, and nanobodies.

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