title: Nucleotide-driven conformational changes in the reverse gyrase helicase-like domain couple the nucleotide cycle to DNA processing.
abstract: Reverse gyrase introduces positive supercoils into DNA in an ATP-dependent process. It has a modular structure comprising a helicase-like and a topoisomerase domain. The helicase-like domain consists of two RecA-like subdomains and thus structurally resembles members of the helicase superfamily 2. It is a nucleotide-dependent switch that alters between an ATP state with a slight preference for dsDNA, and an ADP state with a high preference for ssDNA. Inter-domain communication between the helicase-like and the topoisomerase domain is central for their functional cooperation in reverse gyrase. The latch, an insertion into the helicase-like domain, has been suggested as an important element in coordinating their activities. Here, we have dissected the nucleotide cycle of the reverse gyrase helicase-like domain in the absence and presence of different DNA substrates. With this comprehensive thermodynamic characterization of the nucleotide cycle of the helicase-like domain, in combination with single molecule FRET data on the conformation of the helicase-like domain at all stages of the catalytic cycle, a picture emerges as to how the helicase-like domain may guide ATP-dependent positive supercoiling by reverse gyrase.
authors.affiliation: University of Basel, Biozentrum, Dept. of Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
authors.forename: Yoandris
authors.initials: Y
authors.lastname: del Toro Duany
authors.forename: Dagmar
authors.initials: D
authors.lastname: Klostermeier
mesh_terms: D004265:DNA Helicases / Q000737:chemistry*; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism; D008958:Models, Molecular; D009711:Nucleotides / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D020124:Thermotoga maritima / Q000201:enzymology*
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D009711:Nucleotides; D004265:DNA Helicases; C041813:DNA reverse gyrase; D004264:DNA Topoisomerases, Type I