sltB1 (PA4001) encodes soluble lytic transglycosylase B1 (SltB1), a periplasmic family 3 (GH103, MltB-like) lytic transglycosylase of Pseudomonas aeruginosa. The 340-residue precursor carries a cleavable signal peptide but no lipobox, so the mature enzyme is soluble. Lytic transglycosylases cleave the beta-1,4 bond between N-acetylmuramic acid and N-acetylglucosamine in peptidoglycan glycan strands and form 1,6-anhydromuramyl ends; purified SltB1 releases anhydromuropeptides from insoluble peptidoglycan and is more catalytically efficient than the paralogous lipoprotein MltB1. The crystal structure shows a calcium-binding helix-loop-helix (EF-hand-like) motif. SltB1 binds the N-terminal non-penicillin-binding module of PBP2, and sltB1 is clustered with peptidoglycan synthesis genes, suggesting that it acts with the cell elongation machinery in cell wall growth and turnover.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005515 protein binding | IPI PMID:18708507 Interaction of penicillin-binding protein 2 with soluble lyt... | REMOVE | Summary: IPI with PBP2 (G3XCV7) from affinity chromatography and SPR. Reason: Bare protein binding is uninformative and is removed under the protein-binding policy. The SltB1-PBP2 interaction itself is real (full text read) and is recorded in the description and core function. Supporting Evidence: PMID:18708507 Penicillin-binding protein 2 (PBP2) was identified as a binding partner |
| 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 SltB1, MltB1 and SltB3, including this gene. Reason: SltB1 is shown biochemically to be a lytic transglycosylase, and the IBD also stands on E. coli MltB. The gene appearing in its own WITH/FROM reflects its own experimental grounding. 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/sltB1/sltB1-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 SltB released 1,6-anhydromuropeptides from insoluble peptidoglycan with measured Michaelis-Menten parameters. 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: A lytic transglycosylase cleaves peptidoglycan glycan strands into soluble anhydromuropeptides, which is a catabolic step of peptidoglycan; SltB1 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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