title: Vibrational analysis of crystalline tri-L-alanine.
abstract: We have found that tri-L-alanine (Ala3) can crystallize in a parallel-chain beta structure in addition to the previously known antiparallel-chain beta structure. Although the chain conformations in each structure are essentially similar, the ir 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.
authors.affiliation: Biophysics Research Division, University of Michigan, Ann Arbor, 48109.
authors.forename: W
authors.initials: W
authors.lastname: Qian
authors.forename: J
authors.initials: J
authors.lastname: Bandekar
authors.forename: S
authors.initials: S
authors.lastname: Krimm
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D014732:Vibration
chemical_list: D046911:Macromolecular Substances; D009842:Oligopeptides; C039944:alanyl-alanyl-alanine