title: Application of pattern recognition techniques to the analysis of protein crystal structure data. I. Characteristics of per-residue side chain contact frequency distributions.
abstract: A statistical study of amino acid side chain contact interactions was carried out using a data set based on 36 protein structures. For each type of amino acid, a distribution of per-residue inter-side-chain contacts was obtained, over the observed span of zero to 11 contacts per residue. Significant observations included the following: 1) The mean number of inter-side-chain contacts is proportional to side chain surface area with the exception of Lys and Arg. 2) The mean number of contacts was greater for amino acids in beta-sheet relative to alpha-helical regions. 3) The more polar or surface-loving amino acids exhibited non-normal distributions, whereas distributions for the non-polar or interior-loving amino acids fell within accepted limits of normality.
mesh_terms: D000596:Amino Acids; D003461:Crystallography; D006860:Hydrogen Bonding; D007526:Isoelectric Point; D011487:Protein Conformation
chemical_list: D000596:Amino Acids