3p4x

Helicase domain of reverse gyrase from Thermotoga maritima

spinqualitylabelsall models 3p4x, resolution 2.41Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3p4x is a 2 chain structure with sequence from Atcc 43589. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ADP, CL, MG Related: 3oiy, 3p4y Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Reverse gyrase is the only enzyme known to introduce positive supercoils into DNA. Positive supercoiling is achieved by the functional cooperation of a helicase-like and a topoisomerase domain. The isolated helicase-like domain is a DNA-stimulated ATPase, and the isolated topoisomerase domain can relax supercoiled DNA. In the context of reverse gyrase, these individual activities are suppressed or attenuated. The helicase-like domain of Thermotoga maritima reverse gyrase is a nucleotide-dependent conformational switch that binds DNA and ATP cooperatively. It provides a nucleotide-dependent DNA-binding site to reverse gyrase and thus serves as a valuable model for the investigation of the effect of nucleotides on DNA processing by reverse gyrase that is key to its supercoiling activity. To improve our understanding of the structural basis for the functional cooperation of a helicase domain with a DNA topoisomerase, we have determined the structures of the isolated helicase-like domain of T. maritima reverse gyrase in five different conformations. Comparison of these structures reveals extensive domain flexibility in the absence of conformational restrictions by the topoisomerase that is consistent with single-molecule Forster resonance energy transfer experiments presented here. The structure of the first ADP-bound form provides novel details about nucleotide binding to reverse gyrase. It demonstrates that reverse gyrases use the canonical nucleotide binding mode common to superfamily 2 helicases despite large deviations in the conserved motifs. A characteristic insert region adopts drastically different structures in different reverse gyrases. Counterparts of this insert region are located at very different positions in other DNA-processing enzymes but may point toward a general role in DNA strand separation. The Conformational Flexibility of the Helicase-like Domain from Thermotoga maritima Reverse Gyrase Is Restricted by the Topoisomerase Domain.,Del Toro Duany Y, Klostermeier D, Rudolph MG Biochemistry. 2011 Jun 10. PMID:21627332 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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