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Residue 249 in subunit beta regulates ADP inhibition and its phosphate modulation in Escherichia coli ATP synthase

Lapashina, Anna S., Prikhodko, Anastasia S., Shugaeva, Tatiana E., Feniouk, Boris A.
Biochimica et biophysica acta 2019 v.1860 no.3 pp. 181-188
Escherichia coli, H+/K+-exchanging ATPase, H-transporting ATP synthase, active sites, adenosine diphosphate, adenosine triphosphate, adenosinetriphosphatase, amino acids, bacteria, chloroplasts, enzyme activity, hydrolysis, mitochondria, mutation, phosphates, sulfites
ATPase activity of proton-translocating FOF1-ATP synthase (F-type ATPase or F-ATPase) is suppressed in the absence of protonmotive force by several regulatory mechanisms. The most conservative of these mechanisms found in all enzymes studied so far is allosteric inhibition of ATP hydrolysis by MgADP (ADP-inhibition). When MgADP is bound without phosphate in the catalytic site, the enzyme lapses into an inactive state with MgADP trapped.In chloroplasts and mitochondria, as well as in most bacteria, phosphate prevents MgADP inhibition. However, in Escherichia coli ATP synthase ADP-inhibition is relatively weak and phosphate does not prevent it but seems to enhance it.We found that a single amino acid residue in subunit β is responsible for these features of E. coli enzyme. Mutation βL249Q significantly enhanced ADP-inhibition in E. coli ATP synthase, increased the extent of ATP hydrolysis stimulation by sulfite, and rendered the ADP-inhibition sensitive to phosphate in the same manner as observed in FOF1 from mitochondria, chloroplasts, and most aerobic\photosynthetic bacteria.