Homologous-pairing activity of the Bacillus subtilis bacteriophage SPP1 replication protein G35P.
Genetic evidence suggests that the SPP1-encoded gene 35 product (G35P) is essential for phage DNA replication. Purified G35P binds single-strand DNA (ssDNA) and double-strand (dsDNA) and specifically interacts with SPP1-encoded replicative DNA helicase G40P and SSB protein G36P. G35P promotes joint molecule formation between a circular ssDNA and a homologous linear dsDNA with an ssDNA tail. Joint molecule formation requires a metal ion but is independent of a nucleotide cofactor. Joint molecules formed during these reactions contain a displaced linear ssDNA strand. Electron microscopic analysis shows that G35P forms a multimeric ring structure in ssDNA tails of dsDNA molecules and left-handed filaments on ssDNA. G35P promotes strand annealing at the AT-rich region of SPP1 oriL on a supercoiled template. These results altogether are consistent with the hypothesis that the homologous pairing catalyzed by G35P is an integral part of SPP1 DNA replication. The loading of G40P at a d-loop (ori DNA or at any stalled replication fork) by G35P could lead to replication fork reactivation.
Ayora
Silvia
S
Departmento de Biotecnologia Microbiana, Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Cientificas, Campus Universidad Autónoma de Madrid, Madrid 28049, Spain.
Missich
Riccardo
R
Mesa
Pablo
P
Lurz
Rudi
R
Yang
Shixin
S
Egelman
Edward H
EH
Alonso
Juan C
JC
D000255:Adenosine Triphosphate / Q000378:metabolism; D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D015153:Blotting, Western; D002384:Catalysis; D002845:Chromatography; D004247:DNA / Q000378:metabolism; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008854:Microscopy, Electron; D008954:Models, Biological; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D020161:Physical Chromosome Mapping; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*
D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C467734:G35P protein, bacteriophage SPP1; D017361:Viral Nonstructural Proteins; D000255:Adenosine Triphosphate; D004247:DNA; D008274:Magnesium