Characterization of a novel Streptococcus thermophilus rolling-circle plasmid used for vector construction.
The complete nucleotide sequence of pER371, a native plasmid in Streptococcus thermophilus ST137, was determined. A putative open reading frame coding for a replication protein, Rep371, was identified. A characteristic promoter sequence and ribosome-binding site were found upstream of rep371. Rep371 (247 amino acid residues) does not show homology with RepA and RepS of the small S. thermophilus cryptic plasmids pST1-No.29 and pST1 respectively. The plus-origin sequence and Rep371 are highly homologous to the corresponding elements of the Staphylococcus aureus plasmids pC194 and pSK89. A novel 140-nucleotide palindromic minusorigin sequence, which is structurally similar but does not show sequence homology to the palA region of pC194, was identified in pER371. A palindromic sequence capable of forming a putative hairpin structure was identified and subsequently recognized as being highly conserved among several lactococcal rolling-circle plasmids. Cloning vectors derived from pER371 should provide valuable gene-delivery vehicles for the genetic engineering of lactic acid bacteria.
Solaiman
D K
DK
U.S. Department of Agriculture, ARS, Eastern Regional Research Center, Wyndmoor, PA 19038, USA. dsolaiman@arserrc.gov
Somkuti
G A
GA
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D004265:DNA Helicases / Q000235:genetics; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D005822:Genetic Vectors / Q000235:genetics*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D011506:Proteins / Q000235:genetics; D015183:Restriction Mapping; D017422:Sequence Analysis, DNA; D013211:Staphylococcus aureus / Q000235:genetics; D013291:Streptococcus / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics*
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D011506:Proteins; C115107:Rep371 protein, Streptococcus thermophilus; D015534:Trans-Activators; D014764:Viral Proteins; C084785:repS protein, Streptococcus thermophilus; C045264:replication initiator protein; D004265:DNA Helicases