A distinct single-stranded DNA-binding protein encoded by the Lactococcus lactis bacteriophage bIL67

Virology. 2007 Jun 20;363(1):104-12. doi: 10.1016/j.virol.2007.01.023. Epub 2007 Feb 20.

Abstract

Single-stranded binding proteins (SSBs) are found to participate in various processes of DNA metabolism in all known organisms. We describe here a SSB protein encoded by the Lactococcus lactis phage bIL67 orf14 gene. It is the first noted attempt at characterizing a SSB protein from a lactococcal phage. The purified Orf14(bIL67) binds unspecifically to ssDNA with the same high affinity as the canonical Bacillus subtilis SSB. Electrophoretic mobility-shift assays performed with mutagenized Orf14(bIL67) protein derivatives suggest that ssDNA-binding occurs via a putative OB-fold structure predicted by three-dimensional modeling. The native Orf14(bIL67) forms homotetramers as determined by gel filtration studies. These results allow distinguishing the first lactococcal phage protein with single-strand binding affinity, which defines a novel cluster of phage SSBs proteins. The possible role of Orf14(bIL67) in phage multiplication cycle is also discussed.

MeSH terms

  • Amino Acid Sequence
  • Bacteriophages / genetics
  • Bacteriophages / metabolism*
  • DNA, Single-Stranded / metabolism*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / isolation & purification
  • DNA-Binding Proteins / metabolism*
  • Lactococcus lactis / virology*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Structure, Quaternary
  • Viral Proteins / chemistry
  • Viral Proteins / genetics
  • Viral Proteins / isolation & purification
  • Viral Proteins / metabolism*

Substances

  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Viral Proteins