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.
Kampranis
S C
SC
Department of Biochemistry, University of Leicester, University Road, Leicester, LE1 7RH, United Kingdom.
Maxwell
A
A
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