Role of highly central residues of P-loop and it’s flanking region in preserving the archetypal conformation of Walker A motif of diverse P-loop NTPases

P-loop NTPases represent a large and highly diverse protein family that is involved in variety of cellular functions. Walker A motif forms a typical arched conformation, necessary to accommodate the phosphate moiety of the nucleoside tri (or di-) phosphate in P-loop NTPases. The feature that maintains the ancient architecture of P-loop is unidentified and uncharacterized. Here, using a well established global network parameter, closeness centrality, we identify that Walker A and its flanking regions (N- and C-terminal) have high density of globally connected residue positions. We find that closeness centrality of these residue positions are conserved across common structural core of diverse domains of P-loop NTPase fold. Our results suggest the potential role of globally connected residues in maintaining the local conformation of P-loop.