The members of this family are sequences that are similar to TraC () from Rhizobium etli. The gene encoding this protein is one of a group of genes found on plasmid p42a of Rhizobium etli (strain CFN 42/ATCC 51251) that are thought to be involved in the process of plasmid self-transmission. Mobilisation of plasmid p42a is of importance as it is required for transfer of plasmid p42d, the symbiotic plasmid which carries most of the genes required for nodulation and nitrogen fixation by this symbiotic bacterium. The predicted protein products of p42a are similar to known transfer proteins of Agrobacterium tumefaciens plasmid pTiC58 [].
The proteins in this entry are found in the F, P and I-like type IV secretion systems. Gene symbols include TraC (F-type), TrbE/VirB4 (P-type) and TraU (I-type). The proteins contain the Walker A and B motifs and so are putative nucleotide triphosphatases [, ].
This entry represents a central domain found in the type IV secretion system protein TraC from Escherichia coli (strain K12). TraC is required for the assembly of mature F-pilin subunits into extended F pili, thus involved in bacterial conjugation [, ]. This domain is mainly found in proteins from Proteobacteria, and is approximately 170 amino acids in length. It is found in association with PF11130. There are two conserved sequence motifs: GWDL and QGEY.
This entry contains VirB5, a protein that is involved in the type IV DNA secretion systems typified by the Agrobacterium Ti plasmid vir system where it interacts with several other proteins essential for proper pilus formation []. VirB5 is homologous to the IncN (N-type) conjugation system protein TraC []as well as the P-type protein TrbJ and the F-type protein TraE [].
This family of TraC-related proteins is conserved in Proteobacteria. TraC is a cytoplasmic, peripheral membrane protein and is one of the proteins encoded by the F transfer region of the conjugative plasmid that is required for the assembly of F pilin into the mature F pilus structure. F pili are filamentous appendages that help establish the physical contact between donor and recipient cells involved in the conjugation process []. This family also includes predicted ATPases associated with DNA conjugal transfer. These are found both in plasmids and in bacterial chromosomal regions that appear to derive from integrative elements such as conjugative transposons.
