TY - JOUR
T1 - RecO-mediated DNA homology search and annealing is facilitated by SsbA
AU - Manfredi, Candela
AU - Suzuki, Yuki
AU - Yadav, Tribhuwan
AU - Takeyasu, Kunio
AU - Alonso, Juan C.
N1 - Funding Information:
The Ministerio de Ciencia e Innovación (MICINN) (grants BFU2009-07167 and CSD2007-00010); Comunidad de Madrid (grant S-2009MAT-1507 to J.C.A.); Grant-in-aid for Priority Area from the MEXT of Japan (to K.T.) and JSPS (to Y.S.). Funding for open access charge: Spanish Ministry of Science and Innovation.
PY - 2010/11
Y1 - 2010/11
N2 - Bacillus subtilis RecO plays a central role in recombinational repair and genetic recombination by (i) stimulating RecA filamentation onto SsbA-coated single-stranded (ss) DNA, (ii) modulating the extent of RecA-mediated DNA strand exchange and (iii) promoting annealing of complementary DNA strands. Here, we report that RecO-mediated strand annealing is facilitated by cognate SsbA, but not by a heterologous one. Analysis of non-productive intermediates reveals that RecO interacts with SsbA-coated ssDNA, resulting in transient ternary complexes. The self-interaction of ternary complexes via RecO led to the formation of large nucleoprotein complexes. In the presence of homology, SsbA, at the nucleoprotein, removes DNA secondary structures, inhibits spontaneous strand annealing and facilitates RecO loading onto SsbA-ssDNA complex. RecO relieves SsbA inhibition of strand annealing and facilitates transient and random interactions between homologous naked ssDNA molecules. Finally, both proteins lose affinity for duplex DNA. Our results provide a mechanistic framework for rationalizing protein release and dsDNA zippering as coordinated events that are crucial for RecA-independent plasmid transformation.
AB - Bacillus subtilis RecO plays a central role in recombinational repair and genetic recombination by (i) stimulating RecA filamentation onto SsbA-coated single-stranded (ss) DNA, (ii) modulating the extent of RecA-mediated DNA strand exchange and (iii) promoting annealing of complementary DNA strands. Here, we report that RecO-mediated strand annealing is facilitated by cognate SsbA, but not by a heterologous one. Analysis of non-productive intermediates reveals that RecO interacts with SsbA-coated ssDNA, resulting in transient ternary complexes. The self-interaction of ternary complexes via RecO led to the formation of large nucleoprotein complexes. In the presence of homology, SsbA, at the nucleoprotein, removes DNA secondary structures, inhibits spontaneous strand annealing and facilitates RecO loading onto SsbA-ssDNA complex. RecO relieves SsbA inhibition of strand annealing and facilitates transient and random interactions between homologous naked ssDNA molecules. Finally, both proteins lose affinity for duplex DNA. Our results provide a mechanistic framework for rationalizing protein release and dsDNA zippering as coordinated events that are crucial for RecA-independent plasmid transformation.
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U2 - 10.1093/nar/gkq533
DO - 10.1093/nar/gkq533
M3 - Article
C2 - 20581116
AN - SCOPUS:78651286191
VL - 38
SP - 6920
EP - 6929
JO - Nucleic Acids Research
JF - Nucleic Acids Research
SN - 0305-1048
IS - 20
ER -