8amd | pdb_00008amd

Cryo-EM structure of the RecA presynaptic filament from S.pneumoniae

spinqualitylabelsall models 8amd, resolution 3.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8amd is a 5 chain structure with sequence from Bacteriophage sp. and Streptococcus pneumoniae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AGS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A0B7KZM2_STREE 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. It interacts with LexA causing its activation and leading to its autocatalytic cleavage.[HAMAP-Rule:MF_00268] Publication Abstract from PubMed RecA-mediated homologous recombination (HR) is a key mechanism for genome maintenance and plasticity in bacteria. It proceeds through RecA assembly into a dynamic filament on ssDNA, the presynaptic filament, which mediates DNA homology search and ordered DNA strand exchange. Here, we combined structural, single molecule and biochemical approaches to characterize the ATP-dependent assembly mechanism of the presynaptic filament of RecA from Streptococcus pneumoniae (SpRecA), in comparison to the Escherichia coli RecA (EcRecA) paradigm. EcRecA polymerization on ssDNA is assisted by the Single-Stranded DNA Binding (SSB) protein, which unwinds ssDNA secondary structures that block EcRecA nucleofilament growth. We report by direct microscopic analysis of SpRecA filamentation on ssDNA that neither of the two paralogous pneumococcal SSBs could assist the extension of SpRecA nucleopolymers. Instead, we found that the conserved RadA helicase promotes SpRecA nucleofilamentation in an ATP-dependent manner. This allowed us to solve the atomic structure of such a long native SpRecA nucleopolymer by cryoEM stabilized with ATPgammaS. It was found to be equivalent to the crystal structure of the EcRecA filament with a marked difference in how RecA mediates nucleotide orientation in the stretched ssDNA. Then, our results show that SpRecA and EcRecA HR activities are different, in correlation with their distinct ATP-dependent ssDNA binding modes. Assembly mechanism and cryoEM structure of RecA recombination nucleofilaments from Streptococcus pneumoniae.,Hertzog M, Perry TN, Dupaigne P, Serres S, Morales V, Soulet AL, Bell JC, Margeat E, Kowalczykowski SC, Le Cam E, Fronzes R, Polard P Nucleic Acids Res. 2023 Feb 21:gkad080. doi: 10.1093/nar/gkad080. PMID:36806960 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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