Human Rad51 Protein Requires Higher Concentrations of Calcium Ions for D-Loop Formation than for Oligonucleotide Strand Exchange.

ABSTRACT: Human Rad51 protein (HsRad51)-promoted DNA strand exchange, a crucial step in homologous recombination, is regulated by proteins and calcium ions. Both the activator protein Swi5/Sfr1 and Ca²⁺ ions stimulate different reaction steps and induce perpendicular DNA base alignment in the presynaptic complex. To investigate the role of base orientation in the strand exchange reaction, we examined the Ca²⁺ concentration dependence of strand exchange activities and structural changes in the presynaptic complex. Our results show that optimal D-loop formation (strand exchange with closed circular DNA) required Ca²⁺ concentrations greater than 5 mM, whereas 1 mM Ca²⁺ was sufficient for strand exchange between two oligonucleotides. Structural changes indicat

SUBMITTER: Renodon-Corniere A 

PROVIDER: S-EPMC11011376 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature