Title
Discarding functional residues from the substitution table improves predictions of active sites within three-dimensional structures.
Abstract
Substitutions of individual amino acids in proteins may be under very different evolutionary restraints depending on their structural and functional roles. The Environment Specific Substitution Table (ESST) describes the pattern of substitutions in terms of amino acid location within elements of secondary structure, solvent accessibility, and the existence of hydrogen bonds between side chains and neighbouring amino acid residues. Clearly amino acids that have very different local environments in their functional state compared to those in the protein analysed will give rise to inconsistencies in the calculation of amino acid substitution tables. Here, we describe how the calculation of ESSTs can be improved by discarding the functional residues from the calculation of substitution tables. Four categories of functions are examined in this study: protein-protein interactions, protein-nucleic acid interactions, protein-ligand interactions, and catalytic activity of enzymes. Their contributions to residue conservation are measured and investigated. We test our new ESSTs using the program CRESCENDO, designed to predict functional residues by exploiting knowledge of amino acid substitutions, and compare the benchmark results with proteins whose functions have been defined experimentally. The new methodology increases the Z-score by 98% at the active site residues and finds 16% more active sites compared with the old ESST. We also find that discarding amino acids responsible for protein-protein interactions helps in the prediction of those residues although they are not as conserved as the residues of active sites. Our methodology can make the substitution tables better reflect and describe the substitution patterns of amino acids that are under structural restraints only.
Year
DOI
Venue
2008
10.1371/journal.pcbi.1000179
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
conserved sequence,amino acid,protein protein interaction,catalytic activity,enzymes,nucleic acids,sequence alignment,computational biology,proteins,nucleic acid,hydrogen bond,binding sites,enzyme,active site,ligands,secondary structure
Sequence alignment,Protein structure prediction,Conserved sequence,Protein–protein interaction,Biology,Amino acid,Active site,Bioinformatics,Protein secondary structure,Protein structure
Journal
Volume
Issue
ISSN
4
10
1553-7358
Citations 
PageRank 
References 
2
0.65
7
Authors
2
Name
Order
Citations
PageRank
Sungsam Gong1926.31
TOM. L. BLUNDELL237538.60