Sequence analysis and characterization of ∅O1205, a temperate bacteriophage infecting Streptococcus thermophilus CNRZ1205

The complete nucleotide sequence of φO1205, a temperate bacteriophage infecting Streptococcus thermophilus strain CNRZ1205, was determined. The phage genome has a unit length of 43075 bp and appears to be packaged by the so-called headful mechanism. The genomic organization and structure of φO1205 resemble those of several temperate lactococcal phages that display a life-cycle-specific organization, where ORFs believed to be involved in the lysogenic life-cycle are clustered and arranged in an orientation opposite to the ORFs supposedly involved in the lytic life-cycle. Database searches revealed putative functions for several identified ORFs and further indicated that φO1205 is genetically related to a particular group of lactococcal phages. Three genes encoding the major structural proteins were identified on the φO1205 genome. The phage attachment site attP, the bacterial attachment site attB, and the two phage/chromosome junctions attL and attR were identified and found to contain a 40 bp common core sequence.