3m4a

Crystal structure of a bacterial topoisomerase IB in complex with DNA reveals a secondary DNA binding site

spinqualitylabelsall models 3m4a, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3m4a is a 3 chain structure with sequence from Deinococcus radiodurans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.65Å Ligands: ACY, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9RWH8_DEIRA Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Type IB DNA topoisomerases (TopIB) are monomeric enzymes that relax supercoils by cleaving and resealing one strand of duplex DNA within a protein clamp that embraces a approximately 21 DNA segment. A longstanding conundrum concerns the capacity of TopIB enzymes to stabilize intramolecular duplex DNA crossovers and form protein-DNA synaptic filaments. Here we report a structure of Deinococcus radiodurans TopIB in complex with a 12 bp duplex DNA that demonstrates a secondary DNA binding site located on the surface of the C-terminal domain. It comprises a distinctive interface with one strand of the DNA duplex and is conserved in all TopIB enzymes. Modeling of a TopIB with both DNA sites suggests that the secondary site could account for DNA crossover binding, nucleation of DNA synapsis, and generation of a filamentous plectoneme. Mutations of the secondary site eliminate synaptic plectoneme formation without affecting DNA cleavage or supercoil relaxation. Crystal structure of a bacterial topoisomerase IB in complex with DNA reveals a secondary DNA binding site.,Patel A, Yakovleva L, Shuman S, Mondragon A Structure. 2010 Jun 9;18(6):725-33. PMID:20541510 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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