Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: bacillary dysentery [ICD11:
1A02 
, ICD11:
XN7HG ];
infection due to Shigella flexneri [ICD11:
XN7Y2 ]
NCBI PubMed ID: 15136040Publication DOI: 10.1016/j.jmb.2004.03.068Journal NLM ID: 2985088RPublisher: Elsevier
Correspondence: sherwood.casjens
path.utah.edu
Institutions: Department of Pathology, University of Utah Medical School, Salt Lake City, UT 84132, USA
Shigella flexneri temperate bacteriophage Sf6 is of interest in part because its prophage expresses the oac gene that alters the antigenic properties of the surface O-antigen polysaccharide of its host bacterium. We have determined the complete sequence of its 39,044 bp genome. The sequence shows that Sf6 is a member of the canonical lambdoid phage group, and like other phages of this type has a highly mosaic genome. It has chromosomal regions that encode proteins >80% identical with at least 15 different previously characterized lambdoid phages and prophages, but 43% of the genome, including the virion assembly genes, is homologous to the genome of one phage, HK620. An analysis of the nucleotide differences between Sf6 and HK620 indicates that even these similar regions are highly mosaic. This mosaicism suggests ways in which the virion structural proteins might interact with each other. The Sf6 early operons are arranged like a typical lambdoid phage, with 'boundary sequences' often found between functional modules in the 'metabolic' genome domain. By virtue of high degree of similarity in the encoding genes and their DNA target sites, we predict that the integrase, early transcription anti-terminator, CI and Cro repressors, and CII protein of Sf6 have DNA binding specificities very similar to the homologous proteins encoded by phages HK620, lambda, 434 and P22, respectively. The late operon contains two tRNA genes. The Sf6 terminase genes are unusual. Analysis of in vivo initiation of the DNA packaging series showed that the Sf6 apparatus that recognizes DNA for packaging appears to cleave DNA for initiation of packaging series at many sites within a large region of about 1800 bp that includes a possible pac site. This is unlike previously characterized phage packaging mechanisms.
evolution, bacteriophage Sf6, mosaic genome, DNA packaging
Structure type: polymer chemical repeating unit
Location inside paper: p.281
Compound class: O-polysaccharide, O-antigen
Contained glycoepitopes: IEDB_125613,IEDB_125614,IEDB_127514,IEDB_133752,IEDB_133753,IEDB_133754,IEDB_135813,IEDB_135849,IEDB_136105,IEDB_137340,IEDB_141807,IEDB_141815,IEDB_141816,IEDB_142488,IEDB_143253,IEDB_144998,IEDB_146664,IEDB_151531,IEDB_153213,IEDB_225177,IEDB_885823,IEDB_983931,SB_192
Methods: SDS-PAGE, genetic methods
Comments, role: published polymerization frame was shifted for conformity with other records.
NCBI Taxonomy refs (TaxIDs): 623Reference(s) to other database(s): GTC:G92627KF, GlycomeDB:
37257
Show glycosyltransferases
There is only one chemically distinct structure:
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