RT Journal Article SR Electronic T1 Evolution-Based Functional Decomposition of Proteins JF bioRxiv FD Cold Spring Harbor Laboratory SP 022525 DO 10.1101/022525 A1 Olivier Rivoire A1 Kimberly A. Reynolds A1 Rama Ranganathan YR 2015 UL http://biorxiv.org/content/early/2015/07/15/022525.abstract AB The essential biological properties of proteins - folding, biochemical activities, and the capacity to adapt - arise from the global pattern of interactions between amino acid residues. The statistical coupling analysis (SCA) is an approach to defining this pattern that involves the study of amino acid coevolution in an ensemble of sequences comprising a protein family. This approach indicates a functional architecture within proteins in which the basic units are coupled networks of amino acids termed sectors. This evolution-based decomposition has potential for new understandings of the structural basis for protein function, but requires broad further testing by the scientific community. To facilitate this, we present here the principles and practice of the SCA and introduce new methods for sector analysis in a python-based software package. We show that the pattern of amino acid interactions within sectors is linked to the divergence of functional lineages in a multiple sequence alignment - a model for how sector properties might be differentially tuned in members of a protein family. This work provides new tools for understanding the structural basis for protein function and for generally testing the concept of sectors as the principal functional units of proteins.