Hydrolysis of ATP at only one GyrB subunit is sufficient to promote supercoiling by DNA gyrase.
Mutation of Glu42 to Ala in the B subunit of DNA gyrase abolishes ATP hydrolysis but not nucleotide binding. Gyrase complexes that contain one wild-type and one Ala42 mutant B protein were formed, and the ability of such complexes to hydrolyze ATP was investigated. We found that ATP hydrolysis was able to proceed independently only in the wild-type subunit, albeit at a lower rate. With only one ATP molecule hydrolyzed at a time, gyrase could still perform supercoiling, but the limit of this reaction was lower than that observed when both subunits can hydrolyze the nucleotide.
Department of Biochemistry, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom.
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Kampranis
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Maxwell
D000255:Adenosine Triphosphate / Q000378:metabolism*; D001704:Biopolymers; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004278:DNA, Superhelical; D006868:Hydrolysis; D007700:Kinetics
D001704:Biopolymers; D004278:DNA, Superhelical; D000255:Adenosine Triphosphate; D027081:DNA Gyrase; D004250:DNA Topoisomerases, Type II