pilB (PA4526, UniProt P22608) review notes
No deep-research provider was available; the notes below are from my own
reading of the cached publications, PubMed and the UniProt entry.
Identity
- Fetched accession P22608 (PILB_PSEAE), PA4526, 566 aa, matches the
PseudoCAP worklist entry (rank 11).
- GspE / secretion NTPase superfamily; PANTHER PTHR30258:SF1; NCBIfam
TIGR02538 (type_IV_pilB); Pfam MshEN (PF05157) + T2SSE (PF00437); Walker A
ATP site at 326-333 and a C4 zinc site by similarity to Thermus PilF
[file:PSEAE/pilB/pilB-uniprot.txt].
Function
- pilB, pilC and pilD are needed to make pili PMID:1971619.
PilB function is restricted to pilus biogenesis, unlike PilD
PMID:1671384.
- Purified PilB is an ATPase PMID:18174131; it powers extension PMID:18174131; Walker A/B mutations
abolish twitching PMID:18174131.
- Bipolar, cytoplasmic, PilC-dependent localization PMID:15659660.
- Phage D3112 Tip binds and inhibits PilB PMID:25049409.
- PilB is the only extension motor PMID:33593905.
- UniProt records FimX stimulation of PilB ATPase (PubMed:28854278) and PilC
interaction (PubMed:23413032); not cached here, used only via the UniProt
curated text.
Reference check: PMID:18174131
Verified against PubMed: Chiang et al. 2008, Microbiology 154:114-126,
"Functional role of conserved residues ... PilB, PilT and PilU". It is the
correct paper for both pilB and pilU (not a mis-keyed neighbour; PMID:18174132
is the ccmC paper in the same issue, pages 127-138). For pilB the IDA term
(ATP hydrolysis activity) is exactly what the abstract reports.
PseudoCAP IBA-seed assessment
| PTN node |
node term |
n_seeds |
leaf IBAs |
seed annotation (term, evidence, PMID) |
verdict |
rationale |
| PTN001250205 |
GO:0016887 ATP hydrolysis activity |
1 (sole seed) |
90 (36 taxa) |
GO:0016887 ATP hydrolysis activity, IDA, PMID:18174131 (PseudoCAP) |
SOUND |
In vitro ATPase assay of purified P. aeruginosa PilB, reported in the abstract. The Walker A/B and Asp/His box catalytic motifs are invariant across the GspE/PilB extension ATPases, so ATP hydrolysis is a safe and appropriately broad term for this subfamily node. |
The same node also carries an IBD of plasma membrane (is_active_in), seeded
by two other members (P0AFA5, Q00512), which I keep as non-core for PilB
(peripheral, PilC-docked).
Other PseudoCAP rows
- type IV pilus assembly and type IV pilus-dependent motility (IDA,
PMID:1671384): claims correct, accepted. PMID:1671384 is a pilD paper whose
abstract only restates pilB's biogenesis role from PMID:1971619 and has no
motility assay. Recorded SUSPECTED/CHECK source defects (wrong reference for
the motility row, IMP rather than IDA for the assembly row). Full text not
seen, so not overruled.
Decisions summary
- ACCEPT: cytoplasm (EXP, IEA), ATP hydrolysis activity (IBA, IDA, IEA),
type IV pilus-dependent motility (IDA, IMP), type IV pilus assembly (IDA).
- KEEP_AS_NON_CORE: plasma membrane (IBA, is_active_in).
- MODIFY: pilus assembly (IEA) -> type IV pilus assembly; cell motility (IMP)
-> type IV pilus-dependent motility.