Repeated sequences and the sites of genome rearrangements in bacteriophages of Lactobacillus delbrueckii subsp. lactis.

We have sequenced the KIS-element, a 1.5 kb insertion segment present in the genome of Lactobacillus delbrueckii subsp. lactis phage LL-K, but absent from its close relative, phage LL-H. The KIS-element showed some sequence features of a transposable element: it was flanked by direct repeats of a 20 nt long sequence which was in the genome of LL-H as a target sequence. The KIS-element contained two putative ORFs. The C-terminal part of ORF333 consisted of clusters of direct repeats, capable of coding Lys/Arg-Gly-Asp motifs, which are known to be able to bind to glycoproteins. A homologous counterpart of the KIS-element was also found in the genome of prolate-headed L. delbrueckii subsp. lactis phage JCL1032, even though the phage JCL1032 is not a close relative of phage LL-K. The nucleotide sequence comparison between KIS-element and its homologous counterpart in JCL1032 showed that there have occurred several genome rearrangements at the repeat clusters.