PA4079 (Q9HWU9) notes

Review session 2026-10-28 (PseudoCAP IBA-seed protocol, worklist rank 38)

No deep-research provider was available. A PubMed search for "PA4079 Pseudomonas aeruginosa" returns a
single paper (PMID:28524228), which is abstract-only in the cache and has no PMC copy.

Identity

P. aeruginosa PAO1 locus PA4079, UniProt Q9HWU9 (unreviewed, PE 1), 229 aa; submitted name "Probable
dehydrogenase" (ECO:0000313, not evidence).
Classical short-chain dehydrogenase/reductase (SDR): Pfam PF00106 (adh_short), InterPro IPR002347
(SDR_fam), IPR036291 (NAD(P)-binding domain), Gene3D 3.40.50.720 Rossmann fold; PANTHER PTHR45458:SF1.
Four crystal structures (PDB 5WQM, 5WQN apo; 5WQO, 5WQP with NADP). UniProt BINDING features for NADP(+)
at 13 residues are structure-derived (ECO:0007829|PDB:5WQO, PDB:5WQP).

Literature

Li et al. 2017 solved the structure and assayed activity PMID:28524228; the activity
spectrum indicates a carbonyl reductase PMID:28524228. NADP binding orders the
substrate-specificity loop PMID:28524228. Expression
stays high under antibiotic exposure PMID:28524228, and the authors only speculate about drug reduction PMID:28524228.
The physiological substrate is unknown; no mutant phenotype has been reported. I therefore propose no
biological process term.

Annotation decisions

GO:0004090 carbonyl reductase (NADPH) activity (IDA PseudoCAP): ACCEPT. Activity on a broad range of
carbonyl substrates was measured with the purified protein; the NADP-bound structures support the NADPH
cofactor. GO:0004090 is_a GO:0008106 alcohol dehydrogenase (NADP+) activity is_a GO:0016616 (OLS).
GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor (IBA):
MODIFY to GO:0004090 for this gene; the node term itself is a sound, cautious choice.
NEW GO:0050661 NADP binding (IDA PMID:28524228), from the NADP-bound crystal structures.

PseudoCAP IBA-seed assessment

QuickGO (2026-10-28, withFrom=PANTHER:PTN002388087) returns 369 GO:0016616 IBA rows (the worklist, from an
older PAINT release, has 27 leaves in 14 taxa). Leaves span diverse bacteria (several
annotated "csgA", the Myxococcus C-signal SDR homolog), fungi, green algae (Chlamydomonas), diatoms,
oomycetes and a few arthropods (from the first 200 rows inspected); PA4079 is the only seed.

PTN node	node term	n_seeds	leaf IBAs	seed annotation (term, evidence, PMID)	verdict	rationale
PTN002388087	GO:0016616 oxidoreductase activity, acting on the CH-OH group of donors, NAD or NADP as acceptor	1 (sole)	27 (14 taxa) in worklist; 369 in QuickGO	GO:0004090 carbonyl reductase (NADPH) activity, IDA, PMID:28524228 (PseudoCAP)	SOUND	Purified-enzyme activity on a broad range of carbonyl substrates plus NADP-bound structures: direct biochemistry, not a phenotype. Propagating the generic NAD(P)-dependent CH-OH oxidoreductase parent rather than "carbonyl reductase" is an appropriately cautious choice for a large cross-kingdom SDR clade with one characterised member; it is true of essentially every classical SDR with the conserved catalytic tetrad and Rossmann NAD(P) site.