ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Proton magnetic resonance studies at 220 MHz were carried out on synthetic polymers of the repeating tetrapeptide of elastin. Temperature dependence and solvent-mixture dependence of peptide proton chemical shifts were determined for both linear polymers, N-formyl-(Val-Pro-Gly1-Gly2)n-Val OMe where n ≃ 8 and 40, and for cyclic polymers (Val-Pro-Gly1-Gly2)n, where n = 3 and 4. The Gly2 NH was found to be solvent shielded. In addition, by studying the polymers Boc-Val-Pro-Gly1-Gly2-OH, H-Pro-Gly1-Gly2-Val OMe, H(Pro-Gly1-Gly2-Val)3OH, and others, it was demonstrated that the Val C-O immediately preceding the Gly2 NH in the sequence was required for solvent shielding. Also the Gly2 NH resonance is found at higher field than the Gly1 NH resonance. This provides the basis for proposing a β turn in which the Pro and Gly1 residues form the corners, i.e., residues i + 1 and i + 2, and in which the Gly2 NH, residue i + 3 hydrogen bonds to the carbonyl of residue i, the Val residue.Studies on methanol-water solvent systems indicated retention of the β turn as a significant conformational feature. This suggests that the β turn occurs in the elastic fiber, which contains about 60% water but which utilizes association of hydrophobic groups as a primary force in fibrogenesis.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1974.360130614
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