dc.date.accessioned | 2013-03-12T09:09:04Z | |
dc.date.available | 2013-03-12T09:09:04Z | |
dc.date.issued | 2011 | en_US |
dc.date.submitted | 2011-06-27 | en_US |
dc.identifier.citation | Gebreslasie, Hadgu Girmay. Structural determination of a series of synthetic peptide analogues to the 310-helical (Pro138-Gly144) segment of aquaporin-4 by X- ray crystallography. Masteroppgave, University of Oslo, 2011 | en_US |
dc.identifier.uri | http://hdl.handle.net/10852/12721 | |
dc.description.abstract | In order to understand the single crystal X-ray structures of a series of synthetic peptides mimicking the Pro138-Gly144 segment of human AQP4 [1] , we have crystallized and determined the X-ray structures of some of these peptides. The crystal structure of the peptides Boc-Pro-Pro-OH (1), Boc-Aib-Aib-OMe in two polymorphs (2 and 3), Boc-Val-Val-OMe (4), and the tripeptide Boc-allylSer-Aib-Val-OMe (5), were elucidated.
Peptide 1, C15H24N2O5, was designed and synthesized to the corresponding N-terminal Pro138-Pro139 segment of the 310-helix loop C (Pro138-Pro139-Ser140-Val141-Val142-Gly143-Gly144) of the AQP4. The compound crystallized in the orthorhombic space group P212121 with one molecule in the asymmetric unit. tBoc-Pro bond and Pro-Pro along the peptide bond show cis- and trans-conformations (cis-trans), approximately with ω = -8.2° and ω = -174.35°, respectively. Proline residues in 1 adopt incipient Poly-L-proline type I (PPI) and type II (PPII) backbone conformations. Orthorhombic and monoclinic form of the same compound has been determined so far by different authors. Finally, the backbone conformation of 1 is compared with these two forms (orthorhombic and monoclinic form) as well as with the Pro138-Pro139 segment of AQP4 at 1.8 Å and 3.2 Å resolutions.
The peptide C14H26N2O5 was obtained in two polymorphic forms (2 and 3), both exist in the monoclinic space group P21/c and P21/n, respectively with one molecule in the asymmetric unit. The Aib residues in Boc-Aib-Aib-OMe adopt (φ, ψ)-values which are characteristics of helical conformations. The dihedral angles of the peptide backbone show that the Aib residues lie in left- or right-handed 310- /α-helical regions in the Ramachandran plot. The torsion angles indicate values for folded conformations.
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Peptide 4, C16H30N2O5, was designed and synthesized to the corresponding Val141-Val142 segment of the AQP4 loop C. It was crystallized in the orthorhombic space group P212121 with three molecules in the asymmetric unit. Each molecule in the asymmetric unit adopts a β- strand/polyproline II backbone conformation. The main chain functional groups are hydrogen bonded into tapes carrying the characteristics of parallel β-sheets. Each tape has a left-handed twist and thus forms a helix, with six peptide molecules needed to complete a full 360° rotation. A comparison of hydrogen bond lengths and twisting mode is made with other related structures of protected dipeptides. Additionally, a comparison of the backbone conformation is made with that of the Val141-Val142 segment of the water channel aquaporin-4.
Peptide 5, C21H37N3O7, crystallize in the monoclinic space group C2 with a single molecule in the asymmetric unit. A single crystal X-ray diffraction studies of 5 reveals that it adopts a bend (or turn-like structure) without any intramolecular hydrogen bonding. Most of the dihedral angles of the tripeptide 5 fall within the helical region of the Ramachandran plot. | eng |
dc.language.iso | nob | en_US |
dc.title | Structural determination of a series of synthetic peptide analogues to the 310-helical (Pro138-Gly144) segment of aquaporin-4 by X- ray crystallography | en_US |
dc.type | Master thesis | en_US |
dc.date.updated | 2012-04-14 | en_US |
dc.creator.author | Gebreslasie, Hadgu Girmay | en_US |
dc.subject.nsi | VDP::440 | en_US |
dc.identifier.bibliographiccitation | info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft.au=Gebreslasie, Hadgu Girmay&rft.title=Structural determination of a series of synthetic peptide analogues to the 310-helical (Pro138-Gly144) segment of aquaporin-4 by X- ray crystallography&rft.inst=University of Oslo&rft.date=2011&rft.degree=Masteroppgave | en_US |
dc.identifier.urn | URN:NBN:no-28079 | en_US |
dc.type.document | Masteroppgave | en_US |
dc.identifier.duo | 130775 | en_US |
dc.contributor.supervisor | Carl Henrik Gørbitz, Øyvind Jacobsen | en_US |
dc.identifier.bibsys | 121202682 | en_US |
dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/12721/1/submitedxthesis.pdf | |