Premium
Oligomers of β 2 ‐ and of β 3 ‐Homoproline: What are the Secondary Structures of β ‐Peptides Lacking H‐Bonds?
Author(s) -
Abele Stefan,
Vögtli Kurt,
Seebach Dieter
Publication year - 1999
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/(sici)1522-2675(19991006)82:10<1539::aid-hlca1539>3.0.co;2-e
Subject(s) - chemistry , tripeptide , stereochemistry , oligopeptide , enantiomer , protein secondary structure , peptide , derivative (finance) , amide , crystal structure , amino acid , crystallography , organic chemistry , biochemistry , financial economics , economics
To study the role of H‐bonds in stabilizing β ‐peptidic secondary structures, we have synthesized β ‐oligopeptides (up to the octadecamer 12 ) consisting of β 2 ‐ and β 3 ‐homoproline, i.e. , β ‐peptides lacking amide protons. The enantiomer purity of the building block β 2 ‐homoproline (nipecotic acid, 4 ) was determined by HPLC analysis of the N ‐(2,4‐dinitrophenyl) derivative 5 on a Chiralcel‐OD column ( cf. Fig. 2 ). The CD spectra of the all‐( S )‐ β 2 ‐ and all‐( S )‐ β 3 ‐HPro‐containing β ‐peptides display novel and intensive CD patterns which may be indicative of a secondary structure ( cf. Fig. 3 ). It is noteworthy that a distinct CD pattern was observed with the β 3 ‐HPro derivatives containing as few as three residues ( 7a ). The crystal structure of a N ‐deprotected β 3 ‐HPro‐tripeptide 7c is presented ( cf. Figs. 4 and 5 ), and a model for the structure of β ‐peptides consisting of β 3 ‐HPro is discussed ( cf. Figs. 6 and 7 ).