Nucleotide sequence and distribution of the pTR2030 resistance determinant (hsp) which aborts bacteriophage infection in lactococci.
The lactococcal plasmid pTR2030 encodes resistance to bacteriophage attack via two mechanisms, an abortive-infection mechanism, designated Hsp, and a restriction and modification system. We present the complete sequence of the hsp structural gene. The gene is 1,887 base pairs in length and encodes a protein with a predicted molecular mass of 73.8 kilodaltons. The upstream region was cloned in a promoter-screening vector and shown to direct the constitutive expression of the cat-86 gene. An internal probe was used to determine the distribution of the hsp sequence in industrially significant lactococcal strains and to evaluate its relatedness to another lactococcal plasmid implicated in an abortive-infection-type mechanism, pNP40. No homology was detected, suggesting that this gene is not widely distributed in lactococci. Therefore, there are at least two independent abortive-infection genotypes in lactococci.
Hill
C
C
Department of Food Science, North Carolina State University, Raleigh 27695-7624.
Miller
L A
LA
Klaenhammer
T R
TR
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001435:Bacteriophages / Q000472:pathogenicity*; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D007778:Lactobacillus / Q000235:genetics*; D008969:Molecular Sequence Data; D010957:Plasmids
D001426:Bacterial Proteins; D004269:DNA, Bacterial