These notes record the reasoning behind the two non-routine curation actions in
fadA__Q88L01-ai-review.yaml: the REMOVE of GO:0010124 and the NEW
GO:0036125. No OpenScientist deep-research report was generated for this gene, so
everything below is anchored to the cached UniProt records and GOA tables already
in the repository.
The reviewed UniProt entry is a HAMAP-rule-typed FadA: the rule MF_01620 names
the protein 3-ketoacyl-CoA thiolase, assigns EC 2.3.1.16 and Rhea RHEA:21564,
places it in the fatty acid beta-oxidation pathway, and calls it the
"Fatty acid oxidation complex subunit beta"
[file:PSEPK/fadA__Q88L01/fadA__Q88L01-uniprot.txt "HAMAP; MF_01620; FadA; 1."].
Critically, the PANTHER assignment is to the FadA-specific subfamily, not to
the family root:
PANTHER; PTHR43853:SF11; 3-KETOACYL-COA THIOLASE FADA; 1.PANTHER; PTHR43853; 3-KETOACYL-COA THIOLASE, PEROXISOMAL; 1.So both UniProt's rule-based typing and its subfamily assignment describe a
beta-oxidation thiolase, and neither mentions aromatic-compound catabolism.
The annotation is a TreeGrafter electronic inference — GOA records it as
IEA/GO_REF:0000118 with WITH/FROM = PANTHER:PTN002466592
[file:PSEPK/fadA__Q88L01/fadA__Q88L01-goa.tsv]. There is no experimental,
author, or curator-reviewed evidence behind it, so per the repository's guidance
this is an over-propagated electronic inference that may be argued against on
biological grounds rather than a curator judgment to defer to.
The decisive biological argument is that KT2440 runs phenylacetate catabolism
through a dedicated paa operon that has its own thiolase, curated separately
in this repository:
| Gene | Accession | Locus | Product | GO:0010124 source |
|---|---|---|---|---|
| paaJ | Q88HS3 | PP_3280 | 3-oxoadipyl-CoA/3-oxo-5,6-dehydrosuberyl-CoA thiolase (EC 2.3.1.174) | TreeGrafter, PANTHER:PTN001291485 |
| paaH | Q88HS1 | PP_3282 | 3-hydroxyadipyl-CoA dehydrogenase (EC 1.1.1.35) | InterPro2GO, InterPro:IPR011967 |
| paaF | Q88HR9 | PP_3284 | Enoyl-CoA hydratase-isomerase (EC 4.2.1.17) | — (carries GO:0006635 only) |
The load-bearing point is that the thiolase step of the phenylacetate route is
already carried out by a different protein, and fadA's own typing excludes it
from that route: paaJ/PP_3280 is a distinct gene product with its own EC number
(2.3.1.174) acting on the ring-cleavage intermediates, while Q88L01 is assigned to
the FadA-specific subfamily PTHR43853:SF11 and typed by HAMAP rule MF_01620,
both of which confine it to fatty acid beta-oxidation. Under the repository's
guidance that is an over-propagated electronic inference that can be argued
against on biological grounds.
A secondary, non-decisive observation is that paaJ receives GO:0010124 from a
different TreeGrafter node (PTN001291485) than the one that put the term on fadA
(PTN002466592). This is consistent with the term reaching fadA by thiolase-fold
propagation, but it does not settle the matter on its own: two nodes could in
principle both legitimately carry GO:0010124 if two thiolase clades each act in
phenylacetate catabolism. It is recorded as corroboration, not as the argument.
Note for coherence with the neighbouring ACCEPT: PTN002466592 is also among
the sources of the GO:0006635 fatty acid beta-oxidation annotation this review
accepts, where it is joined by UniRule:UR000080052 and UniPathway:UPA00659
[file:PSEPK/fadA__Q88L01/fadA__Q88L01-goa.tsv]. The node itself is a
beta-oxidation node; it is the phenylacetate term sitting on it that is the
anomaly, so removing GO:0010124 does not undercut GO:0006635.
Taken together, GO:0010124 on fadA is family-wide electronic propagation across
the thiolase fold and should be removed rather than merely flagged.
The paralog context matters for the same reason and is recorded here for
auditability: thiolase-fold propagation of pathway-specific terms is expected to
hit multiple KT2440 thiolases, so the presence of GO:0010124 on this entry is not
evidence of a fadA-specific phenylacetate role.
UniProt states the quaternary structure explicitly:
"Heterotetramer of two alpha chains (FadB) and two beta chains (FadA)"
[file:PSEPK/fadA__Q88L01/fadA__Q88L01-uniprot.txt]. The corresponding alpha
subunit is curated in this repository as genes/PSEPK/fadB. GOA carries no
cellular-component term for this complex on Q88L01 — only GO:0005737 cytoplasm —
so the part_of complex annotation is a genuine gap rather than a
re-statement of an existing term, and it is asserted at the level UniProt
actually supports (complex membership, not a new molecular function).
The chain-length range over which the FadBA complex operates, relative to the
other KT2440 thiolase paralogs, is not established by any record consulted here;
it is carried in suggested_questions rather than asserted.