A conserved cysteine acts as an endogenous antioxidant in the P-type plasma membrane H+-ATPase

ABSTRACT: Sulfur-containing amino acid residues function in antioxidative responses, which can be induced by the reactive oxygen species generated by excessive copper and hydrogen peroxide. In all Na+/K+, Ca2+, and H+ pumping P-type ATPases, a cysteine residue is present two residues upstream of the essential aspartate residue, which is obligatorily phosphorylated in each catalytic cycle. Despite its conservation, the function of this cysteine residue was hitherto unknown. In this study, we analyzed the function of the corresponding cysteine residue (Cys-327) in the autoinhibited plasma membrane H+-ATPase isoform 2 (AHA2) from Arabidopsis thaliana by mutagenesis and heterologous expression in a yeast host. Enzyme kinetics of alanine, serine, and leucine substitutions were identical to those of the wild-type pump but the sensitivity of the mutant pumps was increased towards copper and hydrogen peroxide. Additionally, the cysteine residue was prone to oxidation. These data suggest that Cys-327 functions as an endogenous antioxidant in the plasma membrane H+-ATPase, and possibly in other P-type ATPases as well.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Sandra Maass  

LAB HEAD: Dörte Becher

PROVIDER: PXD022964 | Pride | 2021-08-10

REPOSITORIES: Pride