Identification of Calcium-Binding Sites in the Nucleotide Binding Domain of the Plasma Membrane H+-ATPase From Saccharomyces cerevisiae

In this work, several calcium-binding sites were suggested in the nucleotide-binding domain (N-domain) through three-dimensional (3D) structural analysis and molecular dynamics simulation (MDS). The calcium-binding sites consisted mainly of Asp and Glu residues that displayed bidentate coordination geometry. Calcium binding was confirmed in vitro through intrinsic fluorescence quenching of a recombinant N-domain protein and energy-transfer-sensitized Tb3+ luminescence. The calcium ion binds to the H+-ATPase N-domain and is likely directly involved in modulating enzyme activity.

ChemPhysChem