title: Alpha-helix stability in proteins. II. Factors that influence stability at an internal position.
abstract: The solvent-exposed residue Ala32 in the second alpha-helix of barnase was replaced by all other naturally occurring amino acids and the concomitant effects on the protein stability were determined. The results are assumed to reflect both the distinct conformational preferences of the different amino acids and also possible intrahelical interactions. The conformational preferences may be fully rationalized by invoking only a few physical principles. The results agree well with recently experimentally determined rank-order of helix-forming tendencies determined on a model peptide. There is very weak correlation between the results and the experimental host-guest values. There is a weak correlation between our results and the statistical helix propensities and a slightly better correlation with the positional-dependent statistical parameters of J. S. Richardson, and D. C. Richardson.
authors.affiliation: Cambridge Centre for Protein Engineering, Department of Chemistry, University of Cambridge, U.K.
authors.forename: A
authors.initials: A
authors.lastname: Horovitz
authors.forename: J M
authors.initials: JM
authors.lastname: Matthews
authors.forename: A R
authors.initials: AR
authors.lastname: Fersht
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D001426:Bacterial Proteins; D001483:Base Sequence; D004247:DNA; D004563:Electrochemistry; D004795:Enzyme Stability; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011487:Protein Conformation; D011489:Protein Denaturation; D012260:Ribonucleases / Q000737:chemistry* / Q000235:genetics; D012997:Solvents; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D012997:Solvents; D004247:DNA; D012260:Ribonucleases; C019760:Bacillus amyloliquefaciens ribonuclease