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The frequency of ion‐pair substructures in proteins is quantitatively related to electrostatic potential: A statistical model for nonbonded interactions
Author(s) -
Bryant Stephen H.,
Lawrence Charles E.
Publication year - 1991
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340090205
Subject(s) - folding (dsp implementation) , ion , electrostatics , chemistry , function (biology) , statistical physics , thermal , chemical physics , statistical model , thermal fluctuations , physics , thermodynamics , statistics , mathematics , organic chemistry , evolutionary biology , electrical engineering , biology , engineering
A statistical analysis of ion pairs in protein crystal structures shows that their abundance with respect to uncharged controls is accurately predicted by a Botlzmann‐like function of electrostatic potential. It appears that the mechanisms of protein folding and/or evolution combine to produce a “thermal” distribution of local nonbonded interactions, as has been suggested by statistical–mechanical theories. Using this relationship, we develop a maximum likelihood methodology for estimation of apparent energetic parameters from the data base of known structures, and we derive electrostatic potential functions that lead to optimal agreement of observed and predicted ion‐pair frequencies. These are similar to potentials of mean force derived from electrostatic theory, but departure from Coulombic behavior is less than has been suggested.