gbcB (PA5411, Q9HTF3) notes

Sources read on 2026-11-05: UniProt Q9HTF3 (GBMOR_PSEAE), the GOA file, the cached
abstract of PMID:17951379. The PubMed MCP returned no PMC body for PMC2293255 (abstract
only), so the full text of the seed paper was not read. No deep-research provider file
(no keys). The gbdR review (genes/PSEAE/gbdR) uses the same paper.

Biology

A PA14 transposon screen found gbcA (PA5410) and gbcB (PA5411) mutants that grow on
dimethylglycine but not glycine betaine; 13C-choline NMR showed the genes are needed
for GB to DMG conversion
PMID:17951379;
PMID:17951379.
gbcA/gbcB induction by GB or DMG depends on GbdR
PMID:17951379.
GbcB is the reductase component of a two-component Rieske-type glycine betaine
monooxygenase (GbcA is the oxygenase). Domain architecture: N-terminal FAD-binding
FR-type domain (PF00970), NAD-binding domain (PF00175), C-terminal plant-type
[2Fe-2S] ferredoxin domain (PF00111) with four cysteine ligands (UniProt FT BINDING,
PROSITE-ProRule). The catalytic activity (EC 1.14.13.251) and FAD/2Fe-2S cofactors are
assigned in UniProt by similarity to Q1QYU6 (ECO:0000250), not from a P. aeruginosa
assay.
No direct enzymatic assay of P. aeruginosa GbcB was found. GO has no term for
glycine betaine monooxygenase activity (EC 1.14.13.251) (local GO db and OLS searched).

Annotation judgements

GO:0016491 oxidoreductase activity (IBA, IEA, PseudoCAP IDA): the term is true and is
as specific as the gene's own evidence allows; the specific reductase acceptor is not
established. ACCEPT all three rows. The PseudoCAP IDA rests (per the abstract) on mutant
growth and in vivo NMR, which is IMP, not IDA: WRONG_EVIDENCE_CODE, SUSPECTED, since the
full text was not read.
GO:0051537 2Fe-2S cluster binding: ACCEPT (four conserved Cys ligands, PROSITE).
GO:0051536 iron-sulfur cluster binding: TOO_GENERAL (entailed by GO:0051537).
GO:0031457 glycine betaine catabolic process, IMP: ACCEPT, core.

PseudoCAP IBA-seed assessment

Other seeds' experimental support queried live in QuickGO on 2026-11-05.

PTN node	node term	n_seeds	leaf IBAs	seed annotation (term, evidence, PMID)	verdict	rationale	other seeds	IBD stands without this seed?
PTN005342051	GO:0016491 oxidoreductase activity	3	51 (18 taxa)	GO:0016491, IDA, PMID:17951379 (PseudoCAP)	SOUND	Term correct: GbcB is an FAD/NAD/2Fe-2S reductase and the abstract shows gbcAB are needed for GB to DMG conversion. The abstract describes mutant growth and in vivo NMR, so IMP would fit better than IDA (PSEUDOCAP WRONG_EVIDENCE_CODE, SUSPECTED; full text not read).	E. coli Hcr P75824 (EcoCyc IDA GO:0016651 NAD(P)H oxidoreductase, PMID:10651802), M. tuberculosis Hmp P9WJ93 (IDA GO:0036200 and GO:0047086, PMID:19234303)	Yes; both other seeds have IDA support for oxidoreductase descendants

The node term is the most general oxidoreductase term and suits a mixed clade of
FAD/ferredoxin reductases (Hcr, Hmp, GbcB). No GO_CENTRAL defect on PTN005342051.
gbdR (PA5380) seeds a different node (PTN000111456); no shared node in this batch.