Structural consequences of metal complexation of cyclo[Pro-Phe-Phe-Ala-Xaa]2 decapeptides.
Chemistry
; 7(6): 1176-83, 2001 Mar 16.
Article
en En
| MEDLINE
| ID: mdl-11322543
The conformational features of both free and Ca2+-complexed cyclo[Pro-Phe-Phe-Ala-Xaa]2 (with Xaa= Glu(OtBu), Lys(CIZ), Leu, and Ala) in solution have been determined by NMR spectroscopy and extensive distance-geometry calculations. The decapeptides are conformationally homogeneous in solution and show common structural features in their free and complexed forms. The structures of the free form contain only trans peptide bonds and are topologically similar to the structure of gramicidin-S, folded up in two antiparallel extended structures, stabilized by interstrand hydrogen bonds, and closed at both ends by two beta-turns. In contrast, the Ca2+-complexed peptides present two cis peptide bonds and are generally similar to those observed for the metal-complexed forms of antamanide and related analogues, folded into a saddle shape with two beta-turns. The Glu(OtBu)-, Leu-, and Lys(ClZ)-containing peptides examined here maintain the biological activity of the cyclolinopeptide A in their ability to competitively inhibit cholate uptake. The natural antamanide and cyclolinopeptide A are both able to inhibit the uptake of bile salts into hepatocytes. They share the same postulated active sequence Pro-Phe-Phe. Based on our structural results, we conclude that the ability to adopt a global conformation, characterized by a clear amphipathic separation of hydrophobic and hydrophilic surfaces, is an important feature for the functioning of this class of peptides.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Péptidos Cíclicos
/
Calcio
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Chemistry
Asunto de la revista:
QUIMICA
Año:
2001
Tipo del documento:
Article
País de afiliación:
Italia
Pais de publicación:
Alemania