title: Purification and characterization of the single-stranded DNA binding protein from Streptococcus pneumoniae.
abstract: The Escherichia coli single-stranded DNA binding (SSB) protein is a non-sequence-specific DNA binding protein that functions as an accessory factor for the RecA protein-promoted three-strand exchange reaction. An open reading frame encoding a protein similar in size and sequence to the E. coli SSB protein has been identified in the Streptococcus pneumoniae genome. The open reading frame has been cloned, an overexpression system has been developed, and the protein has been purified to greater than 99% homogeneity. The purified protein binds to ssDNA in a manner similar to that of the E. coli SSB protein. The protein also stimulates the S. pneumoniae RecA protein and E. coli RecA protein-promoted strand exchange reactions to an extent similar to that observed with the E. coli SSB protein. These results indicate that the protein is the S. pneumoniae analog of the E. coli SSB protein. The availability of highly-purified S. pneumoniae SSB protein will facilitate the study of the molecular mechanisms of RecA protein-mediated transformational recombination in S. pneumoniae.
authors.affiliation: Department of Biochemistry, The John Hopkins University, School of Public Health, Baltimore, Maryland 21205, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Steffen
authors.forename: F R
authors.initials: FR
authors.lastname: Bryant
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics* / Q000302:isolation & purification*; D016208:Databases, Factual; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011485:Protein Binding; D011938:Rec A Recombinases / Q000378:metabolism; D011995:Recombination, Genetic; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000737:chemistry*
chemical_list: D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D011938:Rec A Recombinases