VirB1-like subfamily. This subfamily includes VirB1 protein, one of twelve proteins making up type IV secretion systems (T4SS). T4SS are macromolecular assemblies generally composed of VirB1-11 and VirD4 proteins, and are used by bacteria to transport material across their membranes. VirB1 acts as a lytic transglycosylase (LT), and is important with respect to piercing the peptidoglycan layer in the periplasm. LTs catalyze the cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetyl-D-glucosamine (GlcNAc) as do "goose-type" lysozymes. However, in addition to this, they also make a new glycosidic bond with the C6 hydroxyl group of the same muramic acid residue. Proteins similar to this family include the soluble and insoluble membrane-bound LTs in bacteria, the LTs in bacteriophage lambda, as well as the eukaryotic "goose-type" lysozymes (goose egg-white lysozyme; GEWL).
Escherichia coli invasion protein IagB and similar proteins. Lytic transglycosylase-like protein, similar to Escherichia coli invasion protein IagB. IagB is encoded within a pathogenicity island in Salmonella enterica and has been shown to degrade polymeric peptidoglycan. IagB-like invasion proteins are implicated in the invasion of eukaryotic host cells by bacteria. Lytic transglycosylase (LT) catalyzes the cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetyl-D-glucosamine (GlcNAc), as do "goose-type" lysozymes. However, in addition to this, they also make a new glycosidic bond with the C6 hydroxyl group of the same muramic acid residue. Members of this family resemble the soluble and insoluble membrane-bound LTs in bacteria and the LTs in bacteriophage lambda.
lytic transglycosylase(LT)-like domain. Members include the soluble and insoluble membrane-bound LTs in bacteria and LTs in bacteriophage lambda. LTs catalyze the cleavage of the beta-1,4-glycosidic bond between N-acetylmuramic acid (MurNAc) and N-acetyl-D-glucosamine (GlcNAc), as do "goose-type" lysozymes. However, in addition to this, they also make a new glycosidic bond with the C6 hydroxyl group of the same muramic acid residue.
Transglycosylase SLT domain. This family is distantly related to pfam00062. Members are found in phages, type II, type III and type IV secretion systems.