ISSN:
0006-3525
Schlagwort(e):
valinomycin analogue
;
ionophore
;
x-ray direct methods
;
structure and function
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The conformation and intermolecular association of [D-Hyi2, L-Hyi4]meso-valinomycin {cyclo[-D-Val-D-Hyi-L-Val-L-Hyi- (D-Val-L-Hyi-L-Val-D-Hyi)2-], C60H102N6O18} in a crystal form obtained from ethanol solution has been determined by x-ray crystallography. Two depsipeptides and one ethanol molecule per asymmetric unit crystallize in space group P21 (Z = 4); a - 14.579, b = 39.795, c = 13.928 Å, β = 116.90, R1 = 0.0757. The molecular conformation is very similar to that observed in the trigonal P32 crystal form obtained from acetone solution [V. Z. Pletnev et al. (1991) Biopolymers, Vol. 31, pp. 409-415]. Both independent molecules in the crystal adopt a similar distorted bracelet structure with a sterically inaccessible, partially formed, ion-binding center that is stabilized by six 4 → 1 type H bonds. The observed conformation accounts for the inability of the molecule to complex ions. Close examination of the three crystallographically independent molecules reveals that differences in the backbone conformation associated with solvent interaction are significantly larger than those associated with hydrophobic van der Waals interactions of crystal packing.© 1997 John Wiley & Sons, Inc. Biopoly 42: 645-650, 1997
Zusätzliches Material:
3 Ill.
Materialart:
Digitale Medien
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