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A theoretical estimate of the energy barriers between stable conformations of the proline dimer
Author(s) -
Venkatachalam C. M.,
Price B. J.,
Krimm S.
Publication year - 1975
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.1975.360140602
Subject(s) - chemistry , dimer , proline , flexibility (engineering) , computational chemistry , ring (chemistry) , order (exchange) , stereochemistry , amino acid , organic chemistry , biochemistry , statistics , mathematics , finance , economics
Semi‐empirical energy calculations for an internal Pro‐Pro dimer are presented that take into account the nature of the flexibility of the proline ring due to its puckering. Calculations show that three stable conformations are available for the dimer: the cis (ω = 0°, ψ = 160°); the trans (ω = 180°, ψ = 160°, also referred to as trans ′); and the cis ′ (ω = 180°, ψ = −40°) conformations. The best conformational pathways between these stable conformations are determined. Calculations also show that the barrier for cis ′– trans ′ conversion is of the same order of magnitude as that for cis – trans conversion.