A Genomic Region of Lactococcal Temperate Bacteriophage TP901-1 Encoding Major Virion Proteins

Abstract

Two major structural proteins, MHP (major head protein) and MTP (major tail protein), from the lactococcal temperate phage TP901-1 were sequenced at their amino acid termini, and derived degenerate oligonucleotides were used to locate the corresponding genes in the phage genome. This genomic region was sequenced. The sequence characterized includes a total of 11 open reading frames (ORFs) showing an operon structure. Upstream of each ORF, except ORFb2and ORFx,potential ribosome-binding sites were found, suggesting independent translation. However, coupled translation is suggested for ORFxand as a possibility for ORFb3and ORFc2,which have ribosome-binding sites located more distant from their start codons. ORFb2may be translationally fused withmhpat a low frequency. Themhpandmtpgenes are transcribed as a 3.7-kb mRNA with at least six additional ORFs. The organization of the genomic region analyzed resembles that of other distantly related phages, providing possible roles for the uncharacterized ORFs.