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          Institute: MPI für Pflanzenzüchtungsforschung     Collection: Dept. Plant Developmental Biology (George Coupland)     Display Documents



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ID: 127296.0, MPI für Pflanzenzüchtungsforschung / Dept. Plant Developmental Biology (George Coupland)
Characterization of two highly similar Rad51 homologs of Physcomitrella patens
Authors:Ayora, S.; Piruat, J. I.; Luna, R.; Reiss, B.; Russo, V. E. A.; Aguilera, A.; Alonso, J. C.
Language:English
Date of Publication (YYYY-MM-DD):2002-02-08
Title of Journal:Journal of Molecular Biology
Journal Abbrev.:J. Mol. Biol.
Volume:316
Issue / Number:1
Start Page:35
End Page:49
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:The moss Physcomitrella patens, which is a land plant with efficient homologous recombination, encodes two Rad51 proteins PpaRad51.1 and PpaRad51.2). The PpaRad51.1 and PpaRad51.2 proteins, which share 94% identity between them, interact with themselves and with each other. Both proteins bind ssDNA and dsDNA in a Mg2+ and pH-dependent manner, with a stoichiometry of similar toone PpaRad51.1 monomer per 3(+/-1) nt or bp and one PpaRad51.2 monomer per 1(+/-0.5) nt or bp, respectively. At neutral pH, a 1.6-fold excess of both proteins is required for ssDNA and dsDNA binding. PpaRad51.1 and PpaRad51.2 show ssDNA- dependent ATPase activity and efficiently promote strand annealing in a nucleotide-independent but in a Mg2+-depenclent manner. Both proteins promote joint-molecule formation, DNA strand invasion and are able to catalyse strand exchange in the presence of Mg2+ and ATP. No further increase in the activities is observed when both proteins are present in the same reaction. None of the PpaRad51 gene products complement the DNA repair and recombination phenotype of Saccharomyces cerevisiae rad51Delta mutants. However, PpaRad51.1 confers a dominant- negative DNA repair phenotype, and both PpaRad51 proteins reduce the levels of double-strand break-induced recombination when overexpressed in S. cerevisiae wt cells. These results suggest that both PpaRad51 proteins are bona fide Rad51 proteins that may contribute, in a different manner, to homologous recombination, and that they might replace ScRad51 in a hypothetical yeast protein complex inactivating different functions required for recombinational repair. (C) 2002 Elsevier Science Ltd.
Free Keywords:DNA recombination; DNA repair; RecA; ATPases; strand exchange
Comment of the Author/Creator:Date: 2002, FEB 8
External Publication Status:published
Document Type:Article
Communicated by:N.N.
Affiliations:MPI für Pflanzenzüchtungsforschung
External Affiliations:CSIC, Ctr Nacl Biotecnol, Dept Biotecnol Microbiana, Campus; Univ Autonoma Madrid, E-28049 Madrid, Spain; CSIC, Ctr Nacl Biotecnol, Dept Biotecnol Microbiana, E-28049 Madrid, Spain; Univ Autonoma Madrid, Dept Biol Mol, E-28049 Madrid, Spain; Univ Sevilla, Dept Genet, E-41012 Seville, Spain; Max Planck Inst Zuchtungsforsch, D-50829 Cologne, Germany; Max Planck Inst Mol Genet, D-14195 Berlin, Germany
Identifiers:ISI:000174025900004 [ID No:1]
ISSN:0022-2836 [ID No:2]
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