A topographically and conformationally constrained, spin-labeled, alpha-amino acid: crystallographic characterization in peptides.
J Pept Res
; 65(6): 564-79, 2005 Jun.
Article
em En
| MEDLINE
| ID: mdl-15885116
ABSTRACT
2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid (TOAC) is a topographically and conformationally restricted, nitroxide containing, C(alpha)-tetrasubstituted alpha-amino acid. Here, we describe the molecular and crystal structures, as determined by X-ray diffraction analyses, of a TOAC terminally protected derivative, the cyclic dipeptide c(TOAC)(2).1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) solvate, and five TOAC-containing, terminally protected, linear peptides ranging in length from tetra- to hepta-peptides. Incipient and fully developed, regular or distorted 3(10)-helical structures are formed by the linear peptides. A detailed discussion on the average geometry and preferred conformation for the TOAC piperidine ring is also reported. The X-ray diffraction structure of an intramolecularly cyclized side product resulting from a C-activated TOAC residue has also been determined.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Cristalografia por Raios X
/
Óxidos N-Cíclicos
Idioma:
En
Revista:
J Pept Res
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Itália