title: Viability and preliminary in vivo characterization of site-directed mutants of Escherichia coli single-stranded DNA-binding protein.
abstract: Site-directed mutations involving selected amino acids of Escherichia coli single-stranded DNA-binding protein (SSB) were tested for their in vivo functionality when introduced into a chromosomal ssb deletion strain on a plasmid. All mutants complemented the ssb deletion for viability when present on a pSC101 derivative. The generation time with ssbW54S doubled in comparison to the ssb+ control, and both the ssbW54S- and ssbH55K-containing strains exhibited temperature sensitivity. ssbH55K, ssbW54S, ssbW88T, and ssbH55Y (ssb-1) strains displayed reduced survival to ultraviolet irradiation, while ssbW40T and ssbF60L strains were comparable to the ssb+ control strain. This study represents the first investigation of the in vivo properties of ssb mutations constructed for in vitro analysis of DNA binding by SSB.
authors.affiliation: Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
authors.forename: L E
authors.initials: LE
authors.lastname: Carlini
authors.forename: R D
authors.initials: RD
authors.lastname: Porter
authors.forename: U
authors.initials: U
authors.lastname: Curth
authors.forename: C
authors.initials: C
authors.lastname: Urbanke
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002872:Chromosome Deletion; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011836:Radiation Tolerance / Q000235:genetics; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins