抄録
A growing body of evidence indicates that a RecA-mediated recombination system exists in chloroplast. However very little is known about mechanism for plastome homologous recombination. Using E. coli producing recombinant protein, we examined the enzymatic properties of chloroplast-targeted RecA homologue, recA-AT, encoded on the Arabidopsis nuclear genome (see Cerutti et al 1992). Although predicted mature recA-AT showed ATPase and DNA-binding activities, it had little strand exchange activity. More detailed characterization revealed that enzymatic properties of the recA-AT were distinct from those of authentic E. coli RecA: the effect of DNA on ATPase activity, the strength of DNA-binding activity and the migration pattern of DNA-protein complex in gel retardation assays. These differences between the recA-AT and the RecA raise a possibility that biochemical mechanism of the plastome homologous recombination is different from that of RecA-mediated homologous recombination in E. coli. Supported by METI/NEDO partly.
