ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The crystal structure of an iodo-derivative of cyclosporin A has been determined in order to elucidate the constitution of this cyclic undecapeptide. Crystals of iodocyclosporin A are monoclinic, a = 10.475(5), b = 19.60(1), c = 21.04(1) Å, β 99.35(2)°, space group P21 (C22, No. 4). The structure was solved by the heavy atom method and refined by block-diagonal least-squares analysis to a final R-factor of 0.135 with hydrogen atoms in calculated positions. The cyclic peptide has a conformation which is partly β-pleated sheet and partly open loop. The structure analysis demonstrates for the first time the reality of a new type of dipeptide hydrogen-bonding, predicted by Pullman from MO calculations and leading to a conformation described by him as C7eq.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19760590509
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