Wzz (Wzz1, Rol; PA3160) is the O-antigen chain-length regulator encoded in the B-band O-specific antigen biosynthesis cluster of Pseudomonas aeruginosa PAO1. It is a 348-residue inner-membrane polysaccharide co-polymerase of the PCP-1 class, with two transmembrane helices flanking a large periplasmic domain and no cytoplasmic kinase domain. Acting with the Wzy polymerase in the Wzx/Wzy-dependent pathway, Wzz1 sets the long modal chain length of B-band O-antigen before it is ligated to lipid A-core; Wzz2 (PA0938) specifies a second, very long modal length. Wzz1 forms dimers in vivo, associates with O-antigen polymer, and complements wzz mutants of P. aeruginosa and E. coli.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004713 protein tyrosine kinase activity | IBA GO_REF:0000033 | REMOVE | Summary: IBA from PTN000794252, seeded by the E. coli BY-kinases Etk (P38134) and Wzc (P76387). Wzz1 is a PCP-1 co-polymerase with no kinase domain. Reason: Wzz1 has two TM helices and a periplasmic domain and ends five residues after TM2: it has none of the cytoplasmic Walker A/B tyrosine-autokinase domain that Wzc and Etk carry. The kinase activity was gained (or kept) only in the PCP-2a branch, so the transfer to Wzz-type leaves is wrong. Propagation Review Root cause: PROPAGATION BAD Failure modes: WRONG ORTHOLOG OR PARALOG FUNCTIONAL DIVERGENCE Sources checked: PANTHER:PTN000794252 · PTN000794252 SUPPORTS SOURCE BUT NOT TARGET Mixed node containing BY-kinases (Wzc, Etk) and kinase-less PCP-1 chain-length regulators (Wzz1, Wzz2, FepE). UniProtKB:P76387 · E. coli Wzc SUPPORTS SOURCE BUT NOT TARGET True BY-kinase; its activity resides in the cytoplasmic domain Wzz lacks. UniProtKB:P38134 · E. coli Etk SUPPORTS SOURCE BUT NOT TARGET True BY-kinase; its activity resides in the cytoplasmic domain Wzz lacks. Supporting Evidence: file:PSEAE/wzz/wzz-uniprot.txt TRANSMEM 319..343 FT /note="Helical" PMID:9045803 This study describes the molecular characterization of the corresponding wzz (rol) gene, responsible for modulating O-antigen chain length. |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA from PTN000794252 (five seeds: Wzz1 itself, Wzz2, E. coli FepE, Wzc and Etk). Wzz1 appearing among its own sources reflects its PseudoCAP row. Reason: Two predicted TM helices and the conserved PCP topology place Wzz1 in the inner membrane, and the node term holds for every member of the co-polymerase clade; three E. coli seeds have direct plasma-membrane evidence. Supporting Evidence: file:PSEAE/wzz/wzz-uniprot.txt TRANSMEM 29..48 FT /note="Helical" FT /evidence="ECO:0000256|SAM:Phobius" |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: Mapping of the UniProt location (cell membrane, multi-pass). Reason: Same claim as the accepted IBA, supported by the two predicted TM helices. Supporting Evidence: file:PSEAE/wzz/wzz-uniprot.txt TRANSMEM 29..48 FT /note="Helical" FT /evidence="ECO:0000256|SAM:Phobius" |
| GO:0009243 O antigen biosynthetic process | IDA PMID:9045803 Pseudomonas aeruginosa B-band O-antigen chain length is modu... | ACCEPT | Summary: PseudoCAP row. wzz knockouts alter B-band O-antigen chain length and the gene complements them. Reason: Wzz acts with Wzy in O-antigen polymerisation and determines chain-length modality, so it takes part in O-antigen synthesis. The evidence is genetic (IMP), not IDA, though the term is sound. Supporting Evidence: PMID:9045803 The P. aeruginosa O5 wzz gene complemented both O5 and O16 wzz mutants as well as an E. coli wzz mutant. |
| GO:0016020 membrane | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro2GO mapping of the Wzz N-terminal domain. Reason: True, but entailed by the accepted GO:0005886 plasma membrane, which is_a membrane. |
| GO:0043165 Gram-negative-bacterium-type cell outer membrane assembly | IDA PMID:12534470 Pseudomonas aeruginosa O-antigen chain length is determined ... | MARK AS OVER ANNOTATED | Summary: PseudoCAP row. The paper shows Wzz1 and Wzz2 set O-antigen modal length; it does not study outer membrane assembly. Reason: Wzz regulates the length of O-antigen made at the inner membrane; the finished LPS is moved to the outer membrane by the Lpt machinery. Making a component of the outer membrane is not assembling it, and GO's assembly term is carried by Lpt and Bam proteins in the reviewed E. coli genes. Kept off the core function as an over-annotation rather than removed, since the full text was not read. Supporting Evidence: PMID:12534470 we have made the novel observation that polymerization of modal chain length-distributed O-antigen occurred before ligation to the lipid A core. |
| GO:0043165 Gram-negative-bacterium-type cell outer membrane assembly | IDA PMID:24309320 Conserved-residue mutations in Wzy affect O-antigen polymeri... | MARK AS OVER ANNOTATED | Summary: PseudoCAP row from a Wzy mutagenesis study in which Wzz1 modality is a readout. Reason: The full text reports O-antigen modality and Wzy stability, not outer membrane assembly; Wzz's role is chain-length regulation during O-antigen synthesis. Supporting Evidence: PMID:24309320 regulation of polymer length is affected by interaction of Wzz with Wzy |
| GO:0043165 Gram-negative-bacterium-type cell outer membrane assembly | ISS PMID:20418877 In vitro bacterial polysaccharide biosynthesis: defining the... | MARK AS OVER ANNOTATED | Summary: PseudoCAP ISS from E. coli Wzz, citing an in vitro reconstitution of O-polysaccharide synthesis. Reason: The cited paper shows that Wzz confers chain-length modality in vitro; it does not address outer membrane assembly. Same judgement as the IDA rows. Supporting Evidence: PMID:20418877 Specific polysaccharide chain length modality was furthermore demonstrated to result from the action of Wzz. |
| GO:0098567 periplasmic side of plasma membrane | IDA PMID:9045803 Pseudomonas aeruginosa B-band O-antigen chain length is modu... | ACCEPT | Summary: PseudoCAP row and a seed of the PTN000794252 plasma-membrane IBD. The topology (two TM helices flanking a large periplasmic domain) puts the bulk of Wzz1 on the periplasmic side. Reason: The location is right for a PCP-1 protein, and GO:0098567 includes proteins embedded in the membrane. The abstract does not describe a localisation assay, so the IDA code cannot be verified here; no defect is filed because the full text may contain one. Supporting Evidence: file:PSEAE/wzz/wzz-uniprot.txt TRANSMEM 319..343 FT /note="Helical" |
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Experiment: Cryo-EM of a PAO1 Wzz1-Wzy complex in nanodiscs, with chain-length analysis of Wzz1 periplasmic-domain variants in a wzz1 wzz2 double mutant.
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