Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Theoretical EXAFS Studies of the Cu(II)-Octapeptide Complex
KTH, School of Chemical Science and Engineering (CHE), Chemistry.
KTH, School of Chemical Science and Engineering (CHE), Chemistry.
(English)Manuscript (Other academic)
National Category
Inorganic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-7299OAI: oai:DiVA.org:kth-7299DiVA: diva2:12263
Note
QC 20100816Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2010-08-16Bibliographically approved
In thesis
1. A Theoretical Investigation of the Octapeptide Region in the Human Prion Protein
Open this publication in new window or tab >>A Theoretical Investigation of the Octapeptide Region in the Human Prion Protein
2007 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [sv]

Den kopparbindande egenskapen hos prionproteiner är sannolikt kopplad till proteinets funtion. Det mänskliga prionproteinet innehåller ett kopparbindande oktapeptidområde, där PHGGGWGQ-sekvensen upprepas fyra gånger i följd. Syftet med detta arbete är att undersöka strukturen och dynamiken i oktapeptidområdet genom att använda teoretiska metoder. Med kvantkemisk strukturoptimering genomfördes en detaljerad jämförelse av växelverkan mellan flera katjoner och det kopparbindande området. Enligt dessa beräkningar är rodium(III) en möjlig ersättare för koppar(II) i NMR-specktroskopiska koordinationsstudier. Alternativa solvatiseringsmodeller i molekyldynamiksimuleringar har också jämförts. Periodiska randvillkor är mest lämpade för användning i de system som undersöks i detta arbete. Molekyldynamiksimuleringar användes för att jämföra oktapeptidområdets struktur och dynamik med och utan kopparjoner. Växelverkan mellan aminosyrornas ringar påverkar starkt strukturen i detta område i frånvaro av kopparjoner. Fyra olika icke-bindande och bindande modeller har studerats, vilka skiljer i sin beskrivning av växelverkan mellan koppar och proteinet. Teoretiska EXAFS spektra beräknades från dem simulerade strukturerna. Spektra som genererats för den bindande modellen är nästan identiska med experimentiella resultat, vilket stöder användandet av den bindande modellen. Detta arbete visar att kopparjoner interagerar med histidin imidazolringens Nδ, deprotonerade amidkväven hos de därpå följande glycinerna samt karbonylsyret hos den andra glycinen. Simuleringarna kunde visa att kopparjonen inte stabilt binder några axiella vattenmolekyler i lösning, till skillnad från en kristallstruktur av koordinationsstrukturen. Indolringen hos tryptofan interagerar direkt med kopparjonen genom stabiliserande katjon-π växelverkan utan direkt medverkan av någon vattenmolekyl. Växelverkan mellan indolringen och kopparjonen var väldefinierad och observerades kunna ske på båda sidor av koordinationsplanet. Molekyldynamiksimuleringarna med kopparjoner och oktapeptidområdet visade hur närvaron av kopparjoner ledde till ett mer strukturerat oktapeptidområde.

Abstract [en]

The copper-binding ability of the prion protein is thought to be closely related to its function. The human prion protein contains a copper-binding octapeptide region, where the octapeptide PHGGGWGQ is repeated four times consecutively. This work focuses on investigation of the structure and the dynamics of the octapeptide region by means of theoretical methods. Quantum chemical structural optimization allowed a detailed comparison of the interaction of several cations at the copper coordination site. These calculations identified rhodium(III) as a potent substitute for copper(II) that could be used to study the coordination site with NMR-spectroscopic methods. Solvation models that could be used in molecular dynamics simulations as an alternative to periodic boundary conditions were evaluated. Periodic boundary conditions are the best method for modeling the aqueous bulk in the kind of systems that are studied in this work. Molecular dynamics simulations were used to compare the behavior of the octapeptide region in the absence and presence of copper ions. Interaction between nonpolar rings strongly influences the structure of the region in the absence of copper ions. Four different non-bonded and bonded models for describing the interaction between copper and the protein were evaluated. Theoretical EXAFS spectra were calculated from the simulated structures. The results obtained for the bonded model are nearly identical with experimental data, which validates the use of the bonded model. This work thus shows strong evidence for copper(II) ions interacting with the octapeptide region through the histidine imidazole Nδ, the deprotonated nitrogen atoms of the following two glycine residues and the carbonyl oxygen atom of the second glycine residue. Notably, the simulations show that the axial sites of the copper ion do not stably coordinate water molecules in solution, as opposed to the crystal structure reported for the coordination site. Instead, the tryptophan indole ring interacted directly with the copper ion through stabilizing cation-π interaction without water mediation. The interaction of the indole ring with the copper ion was well-defined and was observed to occur on both sides of the coordination plane. The investigations of the interaction between copper ions and the octapeptide region with molecular dynamics simulations show how the presence of copper ions results in a more structured octapeptide region.

Place, publisher, year, edition, pages
Stockholm: KTH, 2007. x, 73 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2007:40
Keyword
prion protein; copper; octapeptide; structure; force field parameters; coordination; non-periodic boundary conditions
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:kth:diva-4423 (URN)987-91-7178-719-4 (ISBN)
Public defence
2007-06-15, Sydvästra galleriet, KTHB, Osquars backe 31, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20100816Available from: 2007-06-04 Created: 2007-06-04 Last updated: 2010-08-16Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Riihimäki, Eva-StinaKloo, Lars
By organisation
Chemistry
Inorganic Chemistry

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 43 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf