Structure/function studies on the allosteric mechanism of Rad51 recombinase (549.8)

• DOI: 10.1096/fasebj.28.1_supplement.549.8
• Publication Date: 2021-06-15T17:31:27Z
• Authors: Scott Morrical; Torrey Mandigo; Michelle Silva; Robyn Maher; Nicolas Villanueva; Brian Eckenroth; Karl Zahn; Xinh‐Xinh Nguyen; April Averill
• Keywords: DNA clamp; Replication protein A; HMG-box

Eukaryotic Rad51 recombinase plays a central role in maintaining genome stability by promoting homology‐directed repair of DNA double‐strand breaks and stalled replication forks. forms presynaptic filaments on single‐stranded DNA, which activates the ATPase, homologous pairing, strand exchange activities enzyme. Structure/function studies yeast reveal that coordination between ATP binding sites is mediated residues at protomer‐protomer interface loops L1 L2. Conserved Phe‐187 His‐352 play roles sensing ATP‐bound state Rad51‐ssDNA inducing conformational changes filament are necessary for exchange. An F187A mutant proficient ssDNA‐dependent ATPase activity but deficient exchange, suggesting an inability to couple homology search function Rad51. Mutations locus affect ssDNA‐binding affinity catalytic turnover. H352Y catalyzes single round subsequently fails due nucleotide defect. Meanwhile, new X‐ray crystallographic structures previously unseen details surfaces The indicate conserved aromatic residue Phe‐290 important stabilizing conformation allows optimal contacts Arg‐293 DNA. Results this work will facilitate modeling structural transitions occur during recombination. Grant Funding Source : NIH grant no. P02 CA098993