These host sequences are derived from excision of prophage DNA from random sites scattered over the host genome. This requires fundamental differences in terminase function as compared to more typical terminases that utilize concatemers of phage genomic DNA as a substrate. This is reflected

by the homology between BcepMu TerL and Mu TerL. Another genome feature shared by BcepMu and Mu is the presence of genomic terminal CA dinucleotide repeats, a feature common in many transposons. Furthermore, BcepMu and Mu seem to be morphologically identical. Despite these similarities, BcepMu and its close relative φE255 have marked differences in genome organization and minimal overall protein PD0332991 purchase sequence similarity to Mu, explaining why they have not been grouped TGF-beta inhibitor together. The putative BcepMu MK-4827 concentration transposase is not related to the Mu transposase, TnpA, but instead is a distant member of the Tn552-IS1604 transposase family. The BcepMu genome is organized into two clusters, with genes 1 through 13 encoded on the bottom strand and genes 17 through 52 on the top strand. The cluster of bottom strand genes includes transcription regulators, the transposase, and a number of small genes of unknown function. The lysogeny control region is likely to include

genes 16 and 17, located at the interface of the bottom strand/top strand gene clusters. This is followed by a lysis cassette consisting genes encoding a holin, endolysin, Rz and Rz1. Proteins 27 through 51 encompass the head and tail morphogenesis cassette. The BcepMu tail biosynthetic cassette proteins are recognizably related both in sequence and in gene order to those of coliphage P2. BcepMu is present as a prophage in many B. cenocepacia strains of the human pathogenic ET2 lineage [58, 72]. Phage φE255 is a phage of the soil saprophyte B. thailandensis [NC_009237]. BcepMu phages, however, are not limited to Burkholderia hosts as related Amoxicillin prophage elements

have been identified in the genomic sequence of many other bacteria, for example Chromobacterium violaceum [NP_901809]. 3. Felix O1-like viruses Salmonella phage Felix O1 has a relatively large head (70 nm in diameter) and a tail of 138 × 18 nm characterized by subunits overlapping each other like roof tiles and showing a criss-cross pattern like phages PB-1 and F8. Notably, it exhibits small collars and eight straight tail fibers. Upon contraction, the base plate separates from the sheath. The type virus Felix O1 is widely known as a diagnostic Salmonella-specific phage [21]. Until recently, the genomic sequence (86.1 kb) of phage Felix O1 was unique and was considered, as such, a “”genomic orphan”", but two related genomes have been recently characterized, though their sequences have yet to be deposited to the public databases. They are coliphage wV8 and Erwinia amylovora phage φEa21-4 (DNA sizes 88.5 and 84.6 kb, respectively [73, 74]. 4.