LpxL (PA3242, HtrB2) is one of two HtrB/LpxL-type lipid A late acyltransferases of Pseudomonas aeruginosa. Members of the LpxL/LpxM/LpxP family are inner-membrane enzymes that transfer an acyl chain from acyl-ACP to the Kdo2-lipid IVA precursor, adding a secondary (acyloxyacyl) chain. In P. aeruginosa the secondary laurate and 2-hydroxylaurate chains are added by HtrB1 (PA0011) and HtrB2 (PA3242), each acting at a specific site of lipid A. Loss of either enzyme alters resistance to antibiotics and cationic antimicrobial peptides and increases outer membrane permeability.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule subcellular location mapping (cell inner membrane). Reason: LpxL family enzymes are inner-membrane proteins. Supporting Evidence: file:PSEAE/lpxL/lpxL-uniprot.txt Cell inner membrane |
| GO:0008913 Kdo2-lipid IVA acyltransferase activity | IDA PMID:26223882 Site-specific activity of the acyltransferases HtrB1 and Htr... | ACCEPT | Summary: PseudoCAP IDA seed of PTN004745460 (node term acyltransferase activity). Reason: The paper shows HtrB2 is responsible for site-specific secondary acylation of lipid A; the specific Kdo2-lipid IVA acceptor rests on the family and on curator reading of the full text. Seed verdict SOUND for the node term. Supporting Evidence: PMID:26223882 In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. file:PSEAE/lpxL/lpxL-uniprot.txt Belongs to the LpxL/LpxM/LpxP family |
| GO:0008913 Kdo2-lipid IVA acyltransferase activity | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule (HAMAP MF_01942) mapping. Reason: Agrees with the IDA row. Supporting Evidence: file:PSEAE/lpxL/lpxL-uniprot.txt Belongs to the LpxL/LpxM/LpxP family |
| GO:0009103 lipopolysaccharide biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/UniPathway mapping to LPS biosynthetic process. Reason: Correct pathway context: lipid A is the membrane anchor of LPS. Supporting Evidence: PMID:26223882 In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. |
| GO:0009245 lipid A biosynthetic process | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000770079, seeded by E. coli LpxL (P0ACV0) and this gene. Reason: Secondary acylation of lipid A; the IBD stands on E. coli LpxL. Supporting Evidence: PMID:26223882 In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. |
| GO:0009245 lipid A biosynthetic process | IDA PMID:26223882 Site-specific activity of the acyltransferases HtrB1 and Htr... | ACCEPT | Summary: PseudoCAP IDA seed of PTN000770079 and PTN004745460 (glycolipid biosynthetic process). Reason: Lipid A acylation by HtrB2 shown by lipid A structure analysis; seed verdict SOUND. Supporting Evidence: PMID:26223882 In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. |
| GO:0009245 lipid A biosynthetic process | IEA GO_REF:0000002 | ACCEPT | Summary: InterPro mapping. Reason: As for the IBA row. Supporting Evidence: PMID:26223882 In this study, we were able to show that each gene identified is responsible for site-specific modification of lipid A. |
| GO:0009247 glycolipid biosynthetic process | IEA GO_REF:0000117 | TOO GENERAL | Summary: ARBA mapping to glycolipid biosynthetic process. Reason: Entailed by GO:0009245 lipid A biosynthetic process (is_a glycolipid biosynthetic process), accepted here. |
| GO:0016020 membrane | IBA GO_REF:0000033 | TOO GENERAL | Summary: IBA membrane from PTN004745460. Reason: Entailed by GO:0005886 plasma membrane, accepted here. |
| GO:0016020 membrane | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro membrane mapping. Reason: Entailed by GO:0005886. |
| GO:0016740 transferase activity | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro mapping. Reason: Entailed by GO:0008913. |
| GO:0016746 acyltransferase activity | IBA GO_REF:0000033 | TOO GENERAL | Summary: IBA from PTN004745460, seeded by E. coli LpxL, LpxM, LpxP, M. tuberculosis PatA, PA0011 and this gene. Reason: True; entailed by GO:0008913 Kdo2-lipid IVA acyltransferase activity, accepted here. |
| GO:0016746 acyltransferase activity | IEA GO_REF:0000120 | TOO GENERAL | Summary: UniRule mapping. Reason: Entailed by GO:0008913. |
| GO:0036104 Kdo2-lipid A biosynthetic process | IEA GO_REF:0000120 | ACCEPT | Summary: UniRule/UniPathway mapping to Kdo2-lipid A biosynthetic process. Reason: LpxL acylates Kdo2-lipid IVA, a step of Kdo2-lipid A biosynthesis. Supporting Evidence: file:PSEAE/lpxL/lpxL-uniprot.txt Belongs to the LpxL/LpxM/LpxP family |
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Download this section (compressed HTML)Q: Which lipid A position and acyl donor (laurate vs 2-hydroxylaurate) does HtrB2 use in vitro, and does it require the Kdo2 headgroup as E. coli LpxL does?
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