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Vibrational analysis of crystalline tri‐ L ‐alanine
Author(s) -
Qian Weili,
Bandekar Jagdeesh,
Krimm Samuel
Publication year - 1991
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.360310208
Subject(s) - antiparallel (mathematics) , chemistry , raman spectroscopy , alanine , chain (unit) , crystallography , computational chemistry , stereochemistry , amino acid , biochemistry , physics , quantum mechanics , astronomy , magnetic field , optics
We have found that tri‐ L ‐alanine (Ala 3 ) can crystallize in a parallel‐chain β structure in addition to the previously known antiparallel‐chain β structure. Although the chain conformations in each structure are essentially similar, their and Raman spectra are distinctively different. We have calculated the normal modes of each structure, and can account in significant detail for these differences. This demonstrates the essential validity of our empirically refined force fields, as well as showing that deeper insights into polypeptide and protein structure can be achieved through the rigorous analyses of normal mode calculations.