mltB1 (PA4444) encodes membrane-bound lytic transglycosylase B1 (MltB1), a family 3 (GH103, MltB-like) lytic transglycosylase of Pseudomonas aeruginosa. The 367-residue precursor has a signal peptide followed by a lipobox, and the protein is palmitoylated at Cys17, anchoring it as a lipoprotein to the periplasmic face of a membrane. The catalytic SLT domain cleaves the beta-1,4 bond between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan with formation of 1,6-anhydromuramyl ends; a soluble form lacking the lipidated N-terminus releases anhydromuropeptides from insoluble peptidoglycan. Its soluble paralogs SltB1, SltB2 and SltB3 share the same fold and reaction.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0008933 peptidoglycan lytic transglycosylase activity | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from the MltB-like family node PTN002410022, seeded by E. coli MltB (P41052) and the three P. aeruginosa paralogs, including this gene. Reason: MltB1 is shown biochemically to be a lytic transglycosylase, and the IBD also stands on E. coli MltB and the paralogs SltB1 and SltB3. Supporting Evidence: PMID:11790124 Both enzymes produced the same three major soluble products which were identified as anhydromuropeptides based on ESI-MS analysis file:PSEAE/mltB1/mltB1-uniprot.txt IPR011757; Lytic_transglycosylase_MltB |
| GO:0008933 peptidoglycan lytic transglycosylase activity | IDA PMID:11790124 Characterization of soluble and membrane-bound family 3 lyti... | ACCEPT | Summary: PseudoCAP IDA seed of PTN002410022 from the purified-enzyme paper. Reason: Purified sMltB released 1,6-anhydromuropeptides from insoluble peptidoglycan. Seed verdict SOUND. Supporting Evidence: PMID:11790124 Both enzymes produced the same three major soluble products which were identified as anhydromuropeptides based on ESI-MS analysis |
| GO:0009253 peptidoglycan catabolic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA peptidoglycan catabolic process from PTN002410022, seeded by E. coli MltB. Reason: The lytic transglycosylase reaction breaks peptidoglycan into soluble anhydromuropeptides, a catabolic step of peptidoglycan; MltB1 does this in vitro. Supporting Evidence: PMID:11790124 Both enzymes produced the same three major soluble products which were identified as anhydromuropeptides based on ESI-MS analysis |
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