ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
An N methylated residue at the n - 3 position of the chain was used to reduce the maximum number of H-bonds realizable y some D,L-alternating oligopeptides in β4.4-, ↑↑5.6- and ↑↓5.6-helices and thus increase for the oligopeptides, the relative stability of larger β-helices. With D, L-alternating oligoleucines of the series Boc-Leun-OMe, however, this approach did not produce the helices expected. Although ↑↓7.2-helices with only one free NH per strand would theoretically be possible, the N-methylated oligoleucines formed instead flawed β4.4-helices having three free NH's in CHCl3 as well as in other solvents of low polarity. These observations confirm that the stability of β-helices does not depend only on the number of intra-or interstrand H-bonds, and corroborate the idea that β-helices with large cavities are inherently unstable.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19930760129
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