Title
Accounting for epistatic interactions improves the functional analysis of protein structures.
Abstract
Motivation: The constraints under which sequence, structure and function coevolve are not fully understood. Bringing this mutual relationship to light can reveal the molecular basis of binding, catalysis and allostery, thereby identifying function and rationally guiding protein redesign. Underlying these relationships are the epistatic interactions that occur when the consequences of a mutation to a protein are determined by the genetic background in which it occurs. Based on prior data, we hypothesize that epistatic forces operate most strongly between residues nearby in the structure, resulting in smooth evolutionary importance across the structure. Methods and Results: We find that when residue scores of evolutionary importance are distributed smoothly between nearby residues, functional site prediction accuracy improves. Accordingly, we designed a novel measure of evolutionary importance that focuses on the interaction between pairs of structurally neighboring residues. This measure that we term pair-interaction Evolutionary Trace yields greater functional site overlap and better structure-based proteomewide functional predictions. Conclusions: Our data show that the structural smoothness of evolutionary importance is a fundamental feature of the coevolution of sequence, structure and function. Mutations operate on individual residues, but selective pressure depends in part on the extent to which a mutation perturbs interactions with neighboring residues. In practice, this principle led us to redefine the importance of a residue in terms of the importance of its epistatic interactions with neighbors, yielding better annotation of functional residues, motivating experimental validation of a novel functional site in LexA and refining protein function prediction.
Year
DOI
Venue
2013
10.1093/bioinformatics/btt489
BIOINFORMATICS
Keywords
Field
DocType
sequence analysis,algorithms,protein conformation,proteome,proteins,mutation
Functional analysis,Coevolution,Computer science,Epistasis,Bioinformatics,Molecular Sequence Annotation,Protein function prediction,Sequence analysis,Protein structure,Mutation
Journal
Volume
Issue
ISSN
29
21
1367-4803
Citations 
PageRank 
References 
2
0.38
15
Authors
7
Name
Order
Citations
PageRank
Angela D. Wilkins1294.16
Eric Venner2182.06
David C. Marciano320.38
Serkan Erdin4632.80
Benu Atri520.38
Rhonald C. Lua6306.06
Olivier Lichtarge718218.68