2oes
From Proteopedia
MSrecA-native-SSB
Structural highlights
Function[RECA_MYCS2] Required for homologous recombination (HR) and the bypass of mutagenic DNA lesions (double strand breaks, DSB) by the SOS response. Can catalyze the hydrolysis of ATP in the presence of single-stranded DNA, the ATP-dependent uptake of single-stranded DNA by duplex DNA, and the ATP-dependent hybridization of homologous single-stranded DNAs. Numerous X-ray crystals have been resolved under different conditions which indicate the flexibility of the protein, essential to its function. Gln-196 contributes to this plasticity by acting as a switch residue, which transmits the effect of nucleotide binding to the DNA-binding region.[1] [2] [3] 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 PubMedMycobacterium smegmatis RecA and its nucleotide complexes crystallize in three different, but closely related, forms characterized by specific ranges of unit cell dimensions. The six crystals reported here and five reported earlier, all grown under the same or very similar conditions, belong to these three forms, all in space group P6(1). They include one obtained by reducing relative humidity around the crystal. In all crystals, RecA monomers form filaments around a 6(1) screw axis. Thus, the c-dimension of the crystal corresponds to the pitch of the RecA filament. As reported for Escherichia coli RecA, the variation in the pitch among the three forms correlates well with the motion of the C-terminal domain of the RecA monomers with respect to the main domain. The domain motion is compatible with formation of inactive as well as active RecA filaments involving monomers with a fully ordered C domain. It does not appear to influence the movement upon nucleotide-binding of the switch residue, which is believed to provide the trigger for transmitting the effect of nucleotide binding to the DNA-binding region. Interestingly, partial dehydration of the crystal results in the movement of the residue similar to that caused by nucleotide binding. The ordering of the DNA-binding loops, which present ensembles of conformations, is also unaffected by domain motion. The conformation of loop L2 appears to depend upon nucleotide binding, presumably on account of the movement of the switch residue that forms part of the loop. The conformations of loops L1 and L2 are correlated and have implications for intermolecular communications within the RecA filament. The structures resulting from different orientations of the C domain and different conformations of the DNA-binding loops appear to represent snapshots of the RecA at different phases of activity, and provide insights into the mechanism of action of RecA. Snapshots of RecA protein involving movement of the C-domain and different conformations of the DNA-binding loops: crystallographic and comparative analysis of 11 structures of Mycobacterium smegmatis RecA.,Krishna R, Prabu JR, Manjunath GP, Datta S, Chandra NR, Muniyappa K, Vijayan M J Mol Biol. 2007 Apr 6;367(4):1130-44. Epub 2007 Jan 26. PMID:17306300[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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