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  • 1. Abahazi, Emese
    et al.
    Satorhelyi, Peter
    Erdelyi, Balazs
    Vertessy, Beata G.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Paizs, Csaba
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Poppe, Laszlo
    Covalently immobilized Trp60Cys mutant of omega‰-transaminase from Chromobacterium violaceum for kinetic resolution of racemic amines in batch and continuous-flow modes2018In: Biochemical engineering journal, ISSN 1369-703X, E-ISSN 1873-295X, Vol. 132, p. 270-278Article in journal (Refereed)
    Abstract [en]

    Covalent immobilization of an engineered omega-transaminase mutant Trp60Cys from Chromobacterium violaceum (CvTAW60C) was performed on bisepoxide-activated aminoalkyl resins. Activity of the various CvTAW60C preparations was evaluated in kinetic resolution of four racemic amines (rac-1a–d). The most active EA-G-CvTAW60C preparation (CvTAW60C attached to polymeric resin with ethylamine function activated with glycerol diglycidyl ether—EA-G) could perform the kinetic resolution of racemic 4-phenylbutan-2-amine (rac-1a) over 49% conversion up to 19 consecutive reaction cycles or in media containing up to 50% v/v DMSO as cosolvent in batch mode reactions. The immobilization process of CvTAW60C onto the EA-G resin filled in stainless steel bioreactors was also tested in flow-through mode. Kinetic resolution of three racemic amines containing aromatic moieties (rac-1a-c) was performed in continuous-flow mode resulting in easy-to-separate mixture of the corresponding ketone (2a–c) and the non-converted (R)-amine in high enantiopurity (ee(R)-1a-c ≥ 96%).

  • 2.
    Cassimjee, Karim Engelmark
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Humble, Maria Svedendahl
    KTH, School of Biotechnology (BIO), Biochemistry.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Biochemistry.
    Abedi, Vahak
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    Chromobacterium violaceum omega-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4 '-substituted acetophenones, and follows Swain-Lupton parameterisation2012In: Organic and biomolecular chemistry, ISSN 1477-0520, E-ISSN 1477-0539, Vol. 10, no 28, p. 5466-5470Article in journal (Refereed)
    Abstract [en]

    For biocatalytic production of pharmaceutically important chiral amines the.-transaminase enzymes have proven useful. Engineering of these enzymes has to some extent been accomplished by rational design, but mostly by directed evolution. By use of a homology model a key point mutation in Chromobacterium violaceum omega-transaminase was found upon comparison with engineered variants from homologous enzymes. The variant Trp60Cys gave increased specificity for (S)-1-phenylethylamine (29-fold) and 4'-substituted acetophenones (similar to 5-fold). To further study the effect of the mutation the reaction rates were Swain-Lupton parameterised. On comparison with the wild type, reactions of the variant showed increased resonance dependence; this observation together with changed pH optimum and cofactor dependence suggests an altered reaction mechanism.

  • 3.
    Chen, Shan
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Svedendahl Humble, Maria
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Stabilization of an amine transaminase for biocatalysis2016In: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 124, p. 20-28Article in journal (Refereed)
    Abstract [en]

    The amine transaminase from Chromobacterium violaceum (Cv-ATA) is a well-known enzyme to achievechiral amines of high enantiomeric excess in laboratory scales. However, the low operational stabilityof Cv-ATA limits the enzyme applicability on larger scales. In order to improve the operational stabilityof Cv-ATA, and thereby extending its applicability, factors (additives, co-solvents, organic solvents anddifferent temperatures) targeting enzyme stability and activity were explored in order to find out how tostore and apply the enzyme. The present investigation shows that the melting point of Cv-ATA is improvedby adding sucrose or glycerol, separately. Further, by storing the enzyme at higher concentrations and inco-solvents, such as; 50% glycerol, 20% methanol or 10% DMSO, the active dimeric structure of Cv-ATAis retained. Enzyme stored in 50% glycerol at −20◦C was e.g., still fully active after 6 months. Finally,the enzyme performance was improved 5-fold by a co-lyophilization with surfactants prior to usage inisooctane.

  • 4.
    Engelmark Cassimjee, Karim
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Svedendahl Humble, Maria
    KTH, School of Biotechnology (BIO), Biochemistry.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Biochemistry.
    Abedi, Vahak
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    Chromobacterium violaceum ω-Transaminase VariantTrp60Cys Shows Increased Specificity for (S)-1-Phenylethylamine and 4’-Substituted Acetophenones, andFollows Swain-Lupton ParameterisationManuscript (preprint) (Other academic)
  • 5.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Amine Transaminases in Biocatalytic Amine Synthesis2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The use of enzymes, nature´s own catalysts, both isolated or as whole cells to perform chemical transformations is called biocatalysis. As a complement to classical chemical catalysis, biocatalysis can be an environmentally friendly and more economical option in the production and synthesis of chemicals. Research on the application of amine transaminases in synthesis of chiral amines have exploded over the last two decades and interest from the industry is increasing. Amine transaminases are promising catalysts due to their ability to perform reductive amination of ketones with excellent enantioselectivity.

    For a process to be efficient, high substrate specificity of the applied enzyme is an important factor. A variant of Chromobacterium violaceum amine transaminase that was obtained through rational design has an increased specific activity toward (S)-1-phenylethylamine and a set of 4´-substituted acetophenones. This result makes this variant a promising catalyst for the asymmetric synthesis of similar amines.

    Amine transaminase catalyzed asymmetric synthesis of amines generally suffers from unfavorable equilibrium. Two methods that include spontaneous tautomerization and biocatalytic amidation for equilibrium displacement have therefore been developed.

    Efficient assays and screening methods are demanded for the discovery and development of novel amine transaminases. For this purpose, a sensitive fluorescence-based assay that holds promise as a high-throughput screening method was developed.

    One of the major obstacles for application of enzymes in industrial processes is the instability of the enzyme toward harsh conditions. The stability of Chromobacterium violaceum amine transaminase was investigated and improved using co-solvents and other additives. Co-lyophilization with surfactants was also applied to improve the performance of the same enzyme in organic solvents.

  • 6.
    Land, Henrik
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Campillo-Brocal, Jonatan C.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Svedendahl Humble, Maria
    Berglund, Per
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    B-factor Guided Proline Substitutions in Chromobacterium violaceum Amine Transaminase – An Evaluation of the Proline Rule as a Method for Enzyme Stabilization2019In: ChemBioChem (Print), ISSN 1439-4227, E-ISSN 1439-7633, Vol. 20, no 10, p. 1297-1304Article in journal (Refereed)
    Abstract [en]

    Biocatalysis is attracting interest in the chemical industry as a sustainable alternative in large-scale chemical transformations. However, low operational stability of naturally evolved enzymes is a challenge and major efforts are required to engineer protein stability, usually by directed evolution. The development of methods for protein stabilization based on rational design is of great interest, as it would minimize the efforts needed to generate stable enzymes. We hereby present a rational design strategy based on proline substitutions in flexible areas of the protein identified by analyzing B-factors. Several proline substitutions in the amine transaminase from Chromobacterium violaceum were shown to have a positive impact on stability with increased half-life at 60°C by a factor of 2.7 (variant K69P/D218P/K304P/R432P) as well as increased melting temperature by 8.3°C (variant K167P). Finally, the presented method utilizing B-factor analysis in combination with the Proline rule was deemed successful at increasing the stability of this enzyme.

  • 7.
    Land, Henrik
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Hendil-Forssell, Peter
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Martinelle, Mats
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    One-pot biocatalytic amine transaminase/acyl transferase cascade for aqueous formation of amides from aldehydes or ketones2016In: catalysis science & technology, ISSN 2044-4753, Vol. 6, p. 2897-2900Article in journal (Refereed)
    Abstract [en]

    An efficient one-pot one-step biocatalytic amine transaminase/acyl transferase cascade for the formation of amides from the corresponding aldehydes and ketones in aqueous solution has been developed. N-benzyl-2-methoxyacetamide has been synthesized utlilizing the developed cascade in conversions up to 97%. The cascade was also evaluated for the synthesis of chiral amides.

  • 8.
    Land, Henrik
    et al.
    Uppsala university.
    Ruggieri, Federica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Szekrenyi, Anna
    Technishe Universität Darmstadt.
    Fessner, Wolf-Dieter
    Technishe Universität Darmstadt.
    Engineering the Active Site of an (S)-Selective Amine Transaminase for Acceptance of Doubly Bulky Primary AminesManuscript (preprint) (Other academic)
  • 9.
    Land, Henrik
    et al.
    Uppsala University.
    Ruggieri, Federica
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Szekrenyi, Anna
    Fessner, Wolf-Dieter
    Berglund, Per
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Industrial Biotechnology.
    Engineering the Active Site of an (S)-Selective Amine Transaminase for Acceptance of Doubly Bulky Primary Amines2019In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. n/a, no n/aArticle in journal (Refereed)
    Abstract [en]

    A protein engineering approach for expanding the substrate scope of the (S)-selective Chromobacterium violaceum amine transaminase is presented. Amino acid residues in the small binding pocket of the active site were targeted in order to increase the pocket size for acceptance of primary amines bearing two bulky groups. A highly sensitive fluorescence assay was then used to evaluate the generated enzyme variants for their activity towards propyl- and benzyl-substituted screening substrates. The best variant, L59A/F88A, was successfully applied in the kinetic resolution of 1,2-diphenylethylamine using different conditions and substrate loadings. The variant L59A/F88A generated enantiomerically pure (R)-1,2-diphenylethylamine with ee >99 % under all tested conditions. The variant also holds great promise for synthesis of hydrophobic compounds as it shows optimum activity when 20 % (v/v) DMSO is applied as cosolvent. The variant L59A/F88A provides a great addition to the available catalyst toolbox for synthesis of chiral amines, as it is the first published (S)-selective amine transaminase showing activity towards benzyl-substituted primary amines.

  • 10.
    Land, Henrik
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Uppsala University, Sweden.
    Svedendahl Humble, Maria
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Pharem Biotech AB, Sweden.
    YASARA: A tool to obtain structural guidance in biocatalytic investigations2018In: Protein Engineering: Methods and Protocols, Humana Press, 2018, Vol. 1685, p. 43-67Chapter in book (Refereed)
    Abstract [en]

    In biocatalysis, structural knowledge regarding an enzyme and its substrate interactions complements and guides experimental investigations. Structural knowledge regarding an enzyme or a biocatalytic reaction system can be generated through computational techniques, such as homology- or molecular modeling. For this type of computational work, a computer program developed for molecular modeling of proteins is required. Here, we describe the use of the program YASARA Structure. Protocols for two specific biocatalytic applications, including both homology modeling and molecular modeling such as energy minimization, molecular docking simulations and molecular dynamics simulations, are shown. The applications are chosen to give realistic examples showing how structural knowledge through homology and molecular modeling is used to guide biocatalytic investigations and protein engineering studies.

  • 11. Scheidt, Thomas
    et al.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Anderson, Mattias
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Chen, Yujie
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Yi, Dong
    Fessner, Wolf-Dieter
    Fluorescence-Based Kinetic Assay for High-Throughput Discovery and Engineering of Stereoselective omega-Transaminases2015In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 357, no 8, p. 1721-1731Article in journal (Refereed)
    Abstract [en]

    omega-Transaminases are a valuable class of enzymes for the production of chiral amines with either (R)- or (S)-configuration in high optical purity and 100% yield by the biocatalytic reductive amination of prochiral ketones. A versatile new assay was developed to quantify omega-transaminase activity for the kinetic characterization and enantioselectivity typing of novel or engineered enzymes based on the conversion of 1-(6-methoxynaphth-2-yl)alkylamines. The associated release of the acetonaphthone product can be monitored by the development of its bright fluorescence at 450 nm with very high sensitivity and selectivity. The assay principle can be used to quantify omega-transaminase catalysis over a very broad range of enzyme activity. Because of its simplicity and low substrate consumption in microtiter plate format the assay seems suitable for liquid screening campaigns with large library sizes in the directed evolution of optimized transaminases. For assay substrates that incorporate structural variations, an efficient modular synthetic route was developed. This includes racemate resolution by lipase-catalyzed transacylation to furnish enantiomerically pure (R)and (S)-configured amines. The latter are instrumental for the rapid enantioselectivity typing of omega-transaminases. This method was used to characterize two novel (S)-selective taurine-pyruvate transaminases of the subtype 6a from thermophilic Geobacillus thermodenitrificans and G. thermoleovorans.

  • 12. Steffen-Munsberg, F.
    et al.
    Vickers, C.
    Thontowi, A.
    Schätzle, S.
    Meinhardt, T.
    Svedendahl Humble, M.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Biochemistry.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    Bornscheuer, U. T.
    Höhne, M.
    Revealing the Structural Basis of Promiscuous Amine Transaminase Activity2013In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, no 1, p. 154-157Article in journal (Refereed)
  • 13. Steffen-Munsberg, F.
    et al.
    Vickers, C.
    Thontowi, A.
    Schätzle, S.
    Tumlirsch, T.
    Svedendahl Humble, M.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Biochemistry.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    Bornscheuer, U. T.
    Höhne, M.
    Connecting Unexplored Protein Crystal Structures to Enzymatic Function2013In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, no 1, p. 150-153Article in journal (Refereed)
  • 14.
    Steffen-Munsberg, Fabian
    et al.
    KTH, School of Biotechnology (BIO), Industrial Biotechnology. Greifswald University, Germany.
    Vickers, Clare
    Kohls, Hannes
    Land, Henrik
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Mallin, Hendrik
    Nobili, Alberto
    Skalden, Lilly
    van den Bergh, Tom
    Joosten, Henk-Jan
    Berglund, Per
    KTH, School of Biotechnology (BIO), Industrial Biotechnology.
    Höhne, Matthias
    Bornscheuer, Uwe T.
    Bioinformatic analysis of a PLP-dependent enzyme superfamily suitable for biocatalytic applications2015In: Biotechnology Advances, ISSN 0734-9750, E-ISSN 1873-1899, Vol. 33, no 5, p. 566-604Article in journal (Refereed)
    Abstract [en]

    In this review we analyse structure/sequence-function relationships for the superfamily of PLP-dependent enzymes with special emphasis on class III transaminases. Amine transaminases are highly important for applications in biocatalysis in the synthesis of chiral amines. In addition, other enzyme activities such as racemases or decarboxylases are also discussed. The substrate scope and the ability to accept chemically different types of substrates are shown to be reflected in conserved patterns of amino acids around the active site. These findings are condensed in a sequence-function matrix, which facilitates annotation and identification of biocatalytically relevant enzymes and protein engineering thereof.

  • 15.
    Wang, Bo
    et al.
    KTH, School of Biotechnology (BIO), Biochemistry.
    Land, Henrik
    KTH, School of Biotechnology (BIO), Biochemistry.
    Berglund, Per
    KTH, School of Biotechnology (BIO), Biochemistry.
    An efficient single-enzymatic cascade for asymmetric synthesis of chiral amines catalyzed by omega-transaminase2013In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 49, no 2, p. 161-163Article in journal (Refereed)
    Abstract [en]

    An efficient single-enzymatic cascade approach for the asymmetric synthesis of chiral amines has been developed, which applies the amino donor 3-aminocyclohexa-1,5-dienecarboxylic acid spontaneously tautomerizing to reach reaction completion with excellent ee values.

1 - 15 of 15
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