2z43

Structure of a twinned crystal of RadA

spinqualitylabelsall models 2z43, resolution 1.93Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2z43 is a 3 chain structure with sequence from Saccharolobus solfataricus P2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.93Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RADA_SACS2 Involved in DNA repair and in homologous recombination. Binds and assemble on single-stranded DNA to form a nucleoprotein filament. Hydrolyzes ATP in a ssDNA-dependent manner and promotes DNA strand exchange between homologous DNA molecules. 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 RecA family proteins engage in an ATP-dependent DNA strand exchange reaction that includes a ssDNA nucleoprotein helical filament and a homologous dsDNA sequence. In spite of more than 20 years of efforts, the molecular mechanism of homology pairing and strand exchange is still not fully understood. Here we report a crystal structure of Sulfolobus solfataricus RadA overwound right-handed filament with three monomers per helical pitch. This structure reveals conformational details of the first ssDNA binding disordered loop (denoted L1 motif) and the dsDNA binding N-terminal domain (NTD). L1 and NTD together form an outwardly open palm structure on the outer surface of the helical filament. Inside this palm structure, five conserved basic amino acid residues (K27, K60, R117, R223 and R229) surround a 25 A pocket that is wide enough to accommodate anionic ssDNA, dsDNA or both. Biochemical analyses demonstrate that these five positively charged residues are essential for DNA binding and for RadA-catalyzed D-loop formation. We suggest that the overwound right-handed RadA filament represents a functional conformation in the homology search and pairing reaction. A new structural model is proposed for the homologous interactions between a RadA-ssDNA nucleoprotein filament and its dsDNA target. Structural and functional analyses of five conserved positively charged residues in the L1 and N-terminal DNA binding motifs of archaeal RADA protein.,Chen LT, Ko TP, Chang YW, Lin KA, Wang AH, Wang TF PLoS ONE. 2007 Sep 12;2(9):e858. PMID:17848989 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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