Fig 1.
Domain composition of TraG. TraG shows a modular structure. The VirB1 ortholog TraGpIP501 protein (GenBank sequence accession no. CAD44387.1) contains 369 amino acids. A transmembrane helix (TMH) is predicted at the N terminus (positions 20 to 36, HMMTOP), as well as a signal peptide with a putative cleavage site at positions 47 to 48 (SignalP 3.0). A specific lytic transglycosylase (SLT) domain is predicted at positions 80 to 165 (gray box); a cysteine-, histidine-dependent amidohydrolases/peptidases (CHAP) domain is putatively located at the C terminus (positions 243 to 369, white box). A peptidoglycan binding motif is predicted for the SLT domain (conserved domain search).