What unites these viruses, in addition to similar proteomes, is the
presence in each of a cytosine-C5 specific DNA methylase (pfam00145, DNA_methylase, C-5 cytosine-specific DNA methylase; ΦCD119 protein YP_529611.1) and a DNA replication cassette composed of three proteins: a DnaD (primosome recruiting protein, presumably analogous to lambda gpO and P22 gp18; ΦCD119 protein YP_529603.1), a hypothetical protein (misidentified in ΦCD27 as a putative resolvase/integrase and missed entirely in the annotation Pritelivir purchase of ΦCD119) and a single-stranded DNA binding protein. 7. phiKZ-like viruses find more phages φKZ and EL are members of a group of giant phages isolated, to date, only in Pseudomonas species. Their heads are isometric, 120 nm in diameter, and they possess 190 nm-long tails. The phage heads contain an inner body. The DNA of φKZ is over 280 kb in size and has 306 ORFs, most of which are unrelated to ORFS of any known protein , while EL contains 201 ORFs within its 211 kb genome . These two phages and Pseudomonas phage Lin68 have recently been proposed as part of a genus “”phiKZ viruses”" . selleck products We now
consider that the differences (number of ORFs, mol%G+C, protein homologs) between φKZ and EL exclude EL from membership in the same genus. Indeed, the recent analysis of novel Pseudomonas phage 201φ2-1  showed this phage to have a strong correlation to φKZ (167 similar proteins), suggesting that it is a true member of the phiKZ virus genus. 8. PB1-like viruses This genus is named after the first isolated member of this group (PB1) . Morphological and DNA-DNA hybridization 4��8C studies by V. Krylov indicated that the following Pseudomonas phages were related: E79, 16, 109, 352, 1214, FS, 71, 337, φC17, SL2, B17 . The sequences of a number of viruses belonging to this genus, namely F8, BcepF1, PB1, 14-1, LBL3, LMA2, and SN (P.-J. Ceyssens, personal communication) have now been completed. None of these phages encodes
a recognizable integrase, suggesting that they are virulent. Phage F8 is one of the Pseudomonas typing phages from the Lindberg set which includes six more similar phages [93, 94]. It possesses a 70-nm wide head with visible capsomers and a 138 nm-long tail, four short straight tail fibers and a base plate that separates from the sheath upon contraction. The tail exhibits no transverse striations, but presents a criss-cross pattern . This criss-cross pattern is a rare feature that has only been observed in phage Felix O1. BcepF1 was isolated from soil by enrichment culture  using a Burkholderia ambifaria strain as its host (E.J. Summer and C.F. Gonzalez, unpublished).