braG (PA1070, P21630) notes

Review session 2026-11-05 (PseudoCAP IBA-seed protocol, tier 2)

Fetched with just fetch-gene PSEAE P21630 --alias braG; accession matches the
worklist. Reviewed Swiss-Prot entry (BRAG_PSEAE). No deep-research provider was
used; literature is the bra-operon papers already reviewed for braF and braD
(genes/PSEAE/braF, genes/PSEAE/braD). NCBI and Europe PMC search were unavailable.

Literature

BraG is the LivF-type ATPase, last gene of braCDEFG; BraF and BraG carry
ATP-binding sequences and are membrane-associated
PMID:2120183;
PMID:2120183.
Required for LIV-I PMID:2120184.
Reconstitution PMID:1400443;
PMID:1400443.
Johnson et al. 2008 screen (PMID:18833300, full text): Table 2 lists PA1070
with D-Alanine C +/- and L-Alanine C +/- (strain PAK, Mini-Tn5). braG is the
last gene of the operon, so the insertion is not polar on the other bra genes.
PMID:18833300.

Decisions

ACCEPT: ATP binding, ATP hydrolysis, plasma membrane (IEA), branched-chain
amino acid transmembrane transporter activity (IBA contributes_to; IEA).
TOO_GENERAL: L-amino acid transport (IBA, IEA), amino acid transmembrane
transport, branched-chain amino acid transport, neutral amino acid transport,
carboxylic acid transmembrane transport (all entailed by GO:1903801/GO:1904273).
MODIFY: L-alanine transport (IMP) -> GO:1904273 L-alanine import across plasma membrane.
UNDECIDED: D-alanine transmembrane transport (IMP), consistent with braF/braD.
NEW: L-leucine import across plasma membrane (IDA PMID:1400443); ABC
transporter complex, substrate-binding subunit-containing (IDA PMID:1400443).
Counts: ACCEPT 5, TOO_GENERAL 6, MODIFY 1, UNDECIDED 1, NEW 2.

PseudoCAP IBA-seed assessment

PTN000657089 is the LivF ATPase node (73 leaf IBAs, 25 taxa). It also carries an
E. coli LivF-seeded contributes_to GO:0015658 IBD. E. coli LivF (P22731) has IDA
annotations (EcoCyc, PMID:14702302) for L-leucine, L-isoleucine, L-valine and
branched-chain amino acid transport and transporter activity (QuickGO, 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?
PTN000657089	GO:0015807 L-amino acid transport	2 (P21630, P22731)	73 (25 taxa)	GO:0015808 L-alanine transport, IMP, PMID:18833300 (PseudoCAP)	SOUND	The partial L-Ala growth defect is indirect on its own, but L-Ala import by BraCDEFG is shown in proteoliposomes (PMID:1400443), braG is required for LIV-I (PMID:2120184), and the insertion is not polar. The generic node term (an ancestor of the seed term) suits a LivF clade whose substrates are set by the partner binding proteins.	E. coli LivF (P22731), IDA L-leucine/isoleucine/valine transport (PMID:14702302)	Yes; E. coli LivF IDA annotations are descendants of the node term

No source_defects were recorded. The D-alanine PseudoCAP IMP row is not a seed of
this node and is left UNDECIDED, as for braF and braD.