Functional importance of αIle-346 and αIle-348 in the catalytic sites of Escherichia coli ATP synthase.

ABSTRACT: We studied the functional role of highly conserved VISIT-DG sequence residues αIle-346 and αIle-348 in the catalytic sites of Escherichia coli F1Fo ATP synthase. αIle-346 is in close proximity, 2.98 and 3.63 Å, to the two known phosphate binding residues αR376 and βR182; αIle-348 is situated within 3.66 Å from βR182. Single or double mutants of both αI346 and αI348 resulted in a variable loss of oxidative phosphorylation and ATPase activity. Azide, fluoroaluminate, and fluoroscandium caused insignificant to significant inhibition of mutants. Whereas the wild-type enzyme was completely inhibited by NBD-Cl (7-chloro-4-nitrobenzo-2-oxa-1, 3-diazole), a variable extent of inhibition was observed for αI346 and αI348 mutants. MgPi protection against NBD-Cl induced inhibition of wild-type, αI346,

SUBMITTER: Zhao C 

PROVIDER: S-EPMC5884630 | biostudies-literature | 2016 Feb

REPOSITORIES: biostudies-literature