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Conformation of cyclobradykinin by nmr and distance geometry calculations
Author(s) -
Pellegrini Maria,
Mammi Stefano,
Gobbo Marina,
Rocchi Raniero,
Peggion Evaristo
Publication year - 1995
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360360409
Subject(s) - conformational isomerism , chemistry , nuclear magnetic resonance spectroscopy , energy minimization , nuclear overhauser effect , crystallography , two dimensional nuclear magnetic resonance spectroscopy , spectroscopy , nuclear magnetic resonance , stereochemistry , yield (engineering) , molecule , computational chemistry , physics , organic chemistry , quantum mechanics , thermodynamics
The conformation of the head‐to‐tail cyclic analogue of bradykinin in DMSO was investigated by nmr. Three sets of resonances were detected and fully assigned. These were attributed to the presence of three stable conformers, two of which were exchanging on the nmr time scale. A fourth, incomplete set of resonances was detected but not assigned. The three major conformers differ in the conformation at the three X‐Pro bonds present. From nuclear Overhauser effect spectroscopy (NOESY) spectra, three sets of interproton distances were derived and used in NOE‐restrained distance geometry calculations. The resulting structures were refined by energy minimization to yield families of structures. Conformer I is characterized by the presence of two type VIb β‐turns between Arg 1 and Gly 4 and between Phe 5 and Phe 8 . The first β‐turn is present also in conformer II, while an inverse γ‐turn bridging Pro 3 is the most pronounced structural feature of conformer III. © 1995 John Wiley & Sons, Inc.