Understanding the behavioural difference of PPCA among its homologs in C7 family towards recognition of DXCA

TL;DR

This study investigates why PPCA uniquely binds to DXCA among its homologs by analyzing structural and sequence differences, revealing that recognition is driven by primary sequence and 3D conformation.

Contribution

It introduces a graph-theoretic model based on binding sequences to explain the selective recognition of DXCA by PPCA.

Findings

PPCA uniquely interacts with DXCA among homologs.

Recognition is driven by primary sequence and 3D structure.

Graph models differentiate PPCA from homologs.

Abstract

Among all the proteins of Periplasmic C type cytochrome A (PPCA) family obtained from cytochrome C7 found in Geobacter sulfurreducens, PPCA protein can interact with Deoxycholate (DXCA), while its other homologs do not, as observed from the crystal structures. Utilizing the concept of 'structure-function relationship', an effort has been initiated towards understanding the driving force for recognition of DXCA exclusively by PPCA among its homologs. Further, a combinatorial analysis of the binding sequences (contiguous sequence of amino acid residues of binding locations) is performed to build graph-theoretic models, which show that PPCA differs from its homologues. Analysis of the results suggests that the underlying impetus of recognition of DXCA by PPCA is embedded in its primary sequence and 3D conformation.