PA3760 (Q9HXN5) notes

Identity

UniProt Q9HXN5 (TrEMBL, unreviewed, PE 3), 842 aa, locus PA3760, no gene
name. Fetched accession matches the worklist entry (rank 23). The folder is
named by locus tag.
Multidomain fused PTS protein: an N-terminal EIIA (glucose type,
PS51093 PTS EIIA type-1, residues 24-128, active-site His76), an HPr
domain (PS51350, residues 173-261, with HPr His and Ser sites PS00369 and
PS00589), and a full-length Enzyme I (PTS_EIN PF05524, PEP-utilizers
PF00391, PEP-utilizers_C PF02896, NCBIfam TIGR01417 PTS_I_fam). PANTHER
PTHR46244:SF6. TCDB 4.A.1.1.15 (PTS glucose-glucoside family).
This is the EI/HPr/EIIA partner of PA3761 (EIIBC). The two genes sit at
the end of a glucosamine-utilisation operon. PAO1 has two other EI-type
proteins: FruI (PA3562, the fused EI/HPr/EIIA of the fructose PTS) and PtsP
(EI-Ntr).

Literature

Johnson et al. 2008 (PMID:18833300, full text). This is the only functional
study of PA3760. It used a PathoGenesis Mini-Tn5 mutant in strain PAK and
ran a Biolog screen with plate confirmation.
PMID:18833300
PMID:18833300
PMID:18833300
qRT-PCR showed 5.2-fold induction of PA3760 by GlcNAc (Table 3). Table 2
lists the PA3760 mutant as unable to grow on N-acetyl-D-glucosamine.
PubMed searches (PA3760, nagF/nagE, P. aeruginosa N-acetylglucosamine PTS)
found no other study of this protein.

Interpretation

The genetic phenotype (no growth on GlcNAc), the substrate induction and the
operon context all agree, and PA3760 has the domains needed to phosphorylate
an EIIBC. Participation in GlcNAc uptake through the PTS is therefore well
supported for PA3760. The protein does part of the work: it relays the
phosphoryl group from PEP through EI, HPr and EIIA to the PA3761 EIIBC,
which phosphorylates GlcNAc during translocation. FruI is still present in
the PA3760 mutant but does not substitute, so PA3760 is the EI for this
system.
A Tn5 insertion in PA3760 could also be polar on PA3761. That does not
matter for the claim, because both are subunits of the same PTS.
The electronic "kinase activity" row is a keyword mapping. In GO,
PEP-protein phosphotransferase activity (EC 2.7.3.9) sits under
"phosphotransferase activity, nitrogenous group as acceptor", not under
kinase activity.

PseudoCAP IBA-seed assessment

PTN000532509 is an Enzyme I node that also carries a GO:0008965 IBD seeded by
E. coli PtsI (P08839) and E. coli PtsP (P37177, EI-Ntr). Its 43 GO:0015764 leaf
IBAs (25 taxa) include general PtsI proteins (E. coli, Salmonella, B. subtilis,
S. aureus, Streptococcus, Chlamydia, Mycoplasma, Neisseria and others), the
nitrogen-PTS PtsP/EI-Ntr proteins (E. coli, Salmonella, Yersinia, Geobacter,
Shewanella, Bradyrhizobium, Coxiella, and P. aeruginosa G3XD36), multiphosphoryl
transfer proteins dedicated to other sugars (FruB, E. coli FryA and PtsA),
P. aeruginosa FruI, and PA3760.

PTN node	node term	n_seeds	leaf IBAs	seed annotation (term, evidence, PMID)	verdict	rationale
PTN000532509	GO:0015764 N-acetylglucosamine transport	1 (sole)	43 (25 taxa)	GO:0015764, IMP, PMID:18833300 (PseudoCAP)	OVER-SPECIFIC	The seed is sound for PA3760: no growth on GlcNAc, GlcNAc induction and the operon context agree. The node term does not fit the clade. Enzyme I is a general PTS component, so a single sugar substrate is arbitrary for general PtsI. EI-Ntr (PtsP) works in the nitrogen-regulatory PTS, not sugar uptake. FruB, FryA, PtsA and P. aeruginosa FruI belong to systems for other sugars. FruI cannot replace PA3760 for GlcNAc growth, and the FruI mutant is defective only on fructose. The IBD should be withdrawn, or moved to a node confined to the GlcNAc-dedicated fused EIIA-HPr-EI clade if one exists.

A GO_CENTRAL source defect is filed on the IBA row (CHECK: withdraw or
re-place the IBD). The PseudoCAP IMP row itself is correct, so no PseudoCAP
defect is filed.

Decisions summary

ACCEPT: PEP-protein phosphotransferase activity (IBA, IEA); N-acetylglucosamine
transport (IMP, IBA, the latter with a GO_CENTRAL node defect); PTS
(IEA); cytoplasm (IEA).
MODIFY: kinase activity, transferase activity, and transferase activity
transferring phosphorus-containing groups (IEA) -> PEP-protein
phosphotransferase activity.

Leaf evidence check (2026-11-06)

Audit of the GO_CENTRAL defect on PTN000532509, which previously argued from
what the other leaves of the Enzyme I node are called. Leaf membership
confirmed with panther_tree.py node PTN000532509 --leaves (43 leaves, 25
taxa); UniProt entries fetched from rest.uniprot.org.

Leaf	Name and its evidence	Experimental annotations found	Verdict
P08839 (E. coli ptsI)	Curated `RecName` "Phosphoenolpyruvate-protein phosphotransferase", ECO:0000303	PubMed:2960675; EC 2.7.3.9 ECO:0000269	PubMed:12705838
P37177 (E. coli ptsP, EI-Ntr)	Curated `RecName`, ECO:0000303	PubMed:8973315; EC 2.7.3.9 ECO:0000269	PubMed:10473571
Q9HY55 (P. aeruginosa PA3562, "fruI")	`RecName` and EC from ARBA (ECO:0000256	ARBA:ARBA00012232) — a predicted name; gene name `fruI` is ECO:0000313	EMBL (submitter)
P77439 (E. coli fryA, MTP 1)	`RecName` ECO:0000305	PubMed:11361063; PE 1	No experimental GO; `GO:0008965` ISS
P32670 (E. coli ptsA, MTP 2)	`RecName` ECO:0000303	PubMed:7773398; PE 3	None; `GO:0008965` ISS, two NAS rows from ComplexPortal
P45597 (X. campestris fruB)	`RecName` ECO:0000303	PubMed:7496537; PE 3	None; `GO:0008965` ISS

PA3760 itself (Q9HXN5) carries a type-1 PTS EIIA domain (Pfam PF00358,
PROSITE PS51093, PS00371), while all four fused multiphosphoryl leaves carry
the type-2 fructose-class EIIA; P08839 and P37177 carry no EIIA or HPr
domain at all. That domain split, not the names fruB/ptsA/fruI, is what
the node-level objection now rests on, together with the PA3562 growth
phenotype and the experimental non-specificity of E. coli PtsI.

Confidence raised PROBABLE -> CONFIRMED: PMID:18833300 is cached full text and
states the decisive PA3562 fact outright, and the domain content is primary
data checked here.