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Conformational behavior of α,α‐dialkylated peptides
Author(s) -
Barone Vincenzo,
Lelj Francesco,
Bavoso Alfonso,
Di Blasio Benedetto,
Grimaldi Patrizio,
Pavone Vincenzo,
Pedone Carlo
Publication year - 1985
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.360240907
Subject(s) - chemistry , dihedral angle , steric effects , molecule , crystallography , molecular geometry , atom (system on chip) , stereochemistry , computational chemistry , hydrogen bond , organic chemistry , computer science , embedded system
The preferred conformations of N ‐acetyl‐ N ′‐methyl amides of some dialkylglycines have been determined by empirical conformational‐energy calculations; minimum‐energy conformations were located by minimizing the energy with respect to all the dihedral angles of the molecules. The conformational space of these compounds is sterically restricted, and low‐energy conformations are found only in the regions of fully extended and helical structures. Increasing the bulkiness of the substituents on the C α , the fully extended conformation becomes gradually more stable than the helical structure preferred in the cases of dimethylglycine. This trend is, however, strongly dependent on the bond angles between the substituents on the C α atom: In particular, helical structures are favored by standard values (111°) of the N‐C α ‐C′ angle, while fully extended conformations are favored by smaller values of the same angle, as experimentally observed, for instance, in the case of α,α‐di‐ n ‐propylglycine.