Pyrroloisoquinoline-based tetrapeptide analogues mimicking reverse-turn secondary structures.
New pyrroloisoquinoline-based tetrapeptides were synthesized in enantiomerically pure form, and their conformational features were studied by NMR, IR, and molecular-modeling techniques. The presence of a reverse turn was observed in both structures, with the C1 stereochemistry playing a central role in determining stable conformations. In particular, all of the analyses led to the conclusion that a type II' beta-turn is mostly stabilized in tetrapeptide mimic 3a, while a typical inverse gamma-turn geometry is revealed for the diastereoisomer 3b.
Landoni
Nicola
N
Dipartimento di Chimica Organica e Industriale, Università degli Studi di Milano, via G. Venezian 21, 20133 Milano, Italy.
Lesma
Giordano
G
Sacchetti
Alessandro
A
Silvani
Alessandra
A
D007546:Isoquinolines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D018716:Molecular Mimicry; D009010:Monte Carlo Method; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D017433:Protein Structure, Secondary; D013055:Spectrophotometry, Infrared / Q000379:methods; D013237:Stereoisomerism
D007546:Isoquinolines; D009842:Oligopeptides