ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The helix-coil transition has been studied by high-resolution NMR for three water-soluble polypeptides. Such systems are better models for protein behavior than those in TFA-CDCl3 solvent. An upfield shift of ∼7 cps is observed for the α-CH peak of poly(L-glutamic acid) and poly-L-lysine as the helix content increases over the transition. No such shift is found for copoly(L-glutamic acid42, L-lysine28, L-alanine30). The width of the α-CH peak for poly L-lysine increases rapidly as helix content rises but for poly L-glutamic acid and the copolymer, the width of this peak remains unchanged up to 60% helicity. This demonstrates a rapid rate of interconversion between helical and random conformations in partly helical polymer for the latter two polypeptides. All three polymers however, show no apparent α-CH peak at 100% helicity. Side-chain resonance lines also broaden as helix content increases and, to a greater extent, the closer the proton is to the main chain.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1968.360060608
