Conjugative Type 4 Secretion System of a Novel Large Plasmid from the ChemoautotrophTetrathiobacter kashmirensisand Construction of Shuttle Vectors forAlcaligenaceae

• DOI: 10.1128/aem.02521-08
• Publication Date: 2009-05-02T00:33:48Z
• Authors: Bomba Dam; Wriddhiman Ghosh; Sujoy K. Das Gupta
• Keywords: Replicon; Horizontal Gene Transfer; Gene cluster

ABSTRACT Tetrathiobacter spp. and other members of the Alcaligenaceae are metabolically versatile environmentally significant. A novel, ∼60-kb conjugative plasmid, pBTK445, from sulfur chemolithoautotroph kashmirensis , was identified characterized. This plasmid exists at a low copy number 2 to 3 per host chromosome. The portion pBTK445 sequenced so far (∼25 kb) harbors genes putatively involved in replication, transfer functions, partition, UV damage repair. 1,373-bp region as minimal replicon. contains repA gene encoding protein belonging RPA (replication A) superfamily an upstream, iteron-based oriV . contiguous 11-gene cluster homologous various type 4 secretion systems (T4SSs) identified. Insertional inactivation demonstrated that this is functions thus, it named tagB (transfer - associated virB ) locus. core peripheral TagB components show different phylogenetic affinities, suggesting system has evolved by assembling evolutionarily divergent T4SSs. virD4 homolog, nucleoprotein transfer, also present downstream Although resembles IncP plasmids terms its genomic organization presence IncP-specific trbM shows several unique features. Unlike IncP, oriT located close proximity traL which generally TraI locus isolation, upstream significant outcome study construction shuttle vectors for related Alkaligenaceae