aurachin C

CHEBI:90888 EXACT SEEDED antibacterial

What these status tags mean

Curation status describes a workflow state. SEEDED means the record entered through the source-seeding workflow; it does not imply that no later curation occurred. PROPOSED marks an addition awaiting review; REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record. These are workflow decisions, not independently verified human review. Agent-assisted contributions may appear in the record history.

Grounding describes the identifier mapping: EXACT uses an ontology identity asserted by the source; MINTED keeps a local identifier when no defensible ontology identity is available; REVIEW_NEEDED flags an exact structure whose ontology identity needs adjudication. The grounding note retains any unresolved alternatives. These tags do not establish the strength of producer or activity evidence.

A C-type aurachin that is quinolin-4-one which is substituted by a hydroxy group at positions 1, a methyl group at position 2, and a triprenyl group at position 3.

Structure

Standard InChIKey	FIHXCHBEHLCXEG-YEFHWUCQSA-N
SMILES	CC1=C(C(=O)C2=CC=CC=C2N1O)C/C=C(\C)/CC/C=C(\C)/CCC=C(C)C
Stereochemistry	fully defined
Cross-references	npatlas:NPA006757

Filing pathway

Alkaloids — computed by NPClassifier npclassifier.gnps2.org@2026-09-07, which is why it is pinned rather than recomputed. The gene cluster's asserted class is pks, terpene, from MIBiG.

Producer organisms 1

A claim that this taxon makes the compound. The basis says what the evidence addressed — a knockout and a database assertion are not the same claim.

Taxon	Basis	Cluster	Evidence
Streptomyces sp. NCBITaxon:1931	SOURCE_ASSERTION	mibig:BGC0002591	PMID:28420868

Occurrences 5

Somebody found the compound in this organism and cited it. That is not a claim that the organism makes it, and nothing here promotes one to the other.

Taxon	Source	Reference
Streptomyces NCBITaxon:1883	LOTUS	DOI:10.1038/JA.2017.50
Stigmatella aurantiaca NCBITaxon:41	LOTUS	DOI:10.1021/NP8003084
Stigmatella aurantiaca NCBITaxon:41	LOTUS	DOI:10.7164/ANTIBIOTICS.40.258
Stigmatella aurantiaca Sg a15 NCBITaxon:675526	CHEBI	PMID:3106289
Stigmatella erecta NCBITaxon:83460	LOTUS	DOI:10.1021/NP800325Z

Biosynthetic gene clusters 1

Accession	Host	Locus evidence	Genome
mibig:BGC0002591	Streptomyces sp. NCBITaxon:1931	CLUSTER_UNSTATED	genbank:KY810820.1

A locus claim and a taxon claim are different questions. Heterologous expression settles the first and leaves the second where the isolation report left it.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 6 nodes, 5 edges

Database-annotated biosynthetic consumption of aurachin C toward the distinct downstream congener aurachin B by native Sg a15 AuaG/H references. This is not a pathway that forms aurachin C. AuaG net oxidation/rearrangement, AuaH reduction and subsequent spontaneous dehydration are distinguished. Transient epoxide/rearrangement steps, cofactors and byproducts are not separately drawn; this is not a balanced reaction or a stable protein-complex claim. These proteins are not assigned to the source-imported Streptomyces BGC0002591 or its KY810820.1 sequence.

Subject	Predicate	Object	Evidence
Aurachin C	is_annotated_substrate_of	AuaG (Sg a15 native reference)	https://www.uniprot.org/uniprotkb/H1ZZA4/entry https://www.ncbi.nlm.nih.gov/protein/CCD27744.1 reference https://www.uniprot.org/uniprotkb/H1ZZA4/entry evidence type DATABASE_ASSERTION retrieved on 2026-10-11 notes The annotated substrate is aurachin C, also cross-referenced as CHEBI:90888 in the UniProt reaction. FAD, oxygen and NAD(P)H support the annotated oxidation; NADH is preferred. Reviewed UniProtKB entry version 36, sequence version 1; adopted annotation, not an independently inspected primary experiment. UniProt cites DOI:10.1002/anie.201204138 for function. snippet Catalyzes the initial step in the conversion of aurachin C to aurachin B reference https://www.ncbi.nlm.nih.gov/protein/CCD27744.1 evidence type CURATOR_INFERENCE retrieved on 2026-10-11 notes Native Sg a15 reference: auaG, 383 aa, HE580420.1:3328..4479, strand 1. CDS-aware genomic translation, deposited translation, GenPept and UniProt sequences agree exactly without ambiguous residues. GenBank/GenPept name Allostigmatella aurantiaca Sg a15 (NCBITaxon:675526); UniProt names Stigmatella aurantiaca (NCBITaxon:41) and explicitly gives strain Sg a15. Identity rests on sequence and accession/strain links, not taxonomy-label equality. The native reference does not establish the tagged or mutated experimental construct.
AuaG (Sg a15 native reference)	is_annotated_to_produce	Aurachin rearrangement ketone	https://www.uniprot.org/uniprotkb/H1ZZA4/entry reference https://www.uniprot.org/uniprotkb/H1ZZA4/entry evidence type DATABASE_ASSERTION retrieved on 2026-10-11 notes The annotated net product is 4-hydroxy-2-methyl-3-oxo-4-[(2E,6E)-farnesyl]-3,4-dihydroquinoline 1-oxide. The annotation describes epoxidation and semipinacol rearrangement with C3-to-C4 farnesyl migration. No separately trapped intermediate or newly assigned stereochemistry is claimed. Reviewed UniProtKB entry version 36, sequence version 1; adopted annotation, not an independently inspected primary experiment. UniProt cites DOI:10.1002/anie.201204138 for function.
Aurachin rearrangement ketone	is_annotated_substrate_of	AuaH (Sg a15 native reference)	https://www.uniprot.org/uniprotkb/H1ZZB0/entry https://www.ncbi.nlm.nih.gov/protein/CCD27750.1 reference https://www.uniprot.org/uniprotkb/H1ZZB0/entry evidence type DATABASE_ASSERTION retrieved on 2026-10-11 notes AuaH reduces the rearranged ketone in the C-to-B conversion. Both NADH and NADPH are annotated donors, with preference for NADH. The reaction is drawn in the annotated biosynthetic reduction direction, not the reverse direction used to write the database equation. Reviewed UniProtKB entry version 35, sequence version 1; adopted annotation, not an independently inspected primary experiment. UniProt cites DOI:10.1002/anie.201204138 for function. snippet which then undergoes a spontaneous dehydration to form aurachin B reference https://www.ncbi.nlm.nih.gov/protein/CCD27750.1 evidence type CURATOR_INFERENCE retrieved on 2026-10-11 notes Native Sg a15 reference: auaH, 334 aa, HE580421.1:2606..3610, strand -1. CDS-aware genomic translation, deposited translation, GenPept and UniProt sequences agree exactly without ambiguous residues. GenBank/GenPept name Allostigmatella aurantiaca Sg a15 (NCBITaxon:675526); UniProt names Stigmatella aurantiaca (NCBITaxon:41) and explicitly gives strain Sg a15. Identity rests on sequence and accession/strain links, not taxonomy-label equality. The native reference does not establish the tagged or mutated experimental construct.
AuaH (Sg a15 native reference)	is_annotated_to_produce	Reduced aurachin rearrangement intermediate	https://www.uniprot.org/uniprotkb/H1ZZB0/entry reference https://www.uniprot.org/uniprotkb/H1ZZB0/entry evidence type DATABASE_ASSERTION retrieved on 2026-10-11 notes The annotated immediate reduction product is 3,4-dihydroxy-2-methyl-4-[(2E,6E)-farnesyl]-3,4-dihydroquinoline 1-oxide. AuaH is not drawn as a dehydration catalyst. Reviewed UniProtKB entry version 35, sequence version 1; adopted annotation, not an independently inspected primary experiment. UniProt cites DOI:10.1002/anie.201204138 for function.
Reduced aurachin rearrangement intermediate	is_annotated_to_spontaneously_dehydrate_to	Aurachin B	https://www.uniprot.org/uniprotkb/H1ZZB0/entry reference https://www.uniprot.org/uniprotkb/H1ZZB0/entry evidence type DATABASE_ASSERTION retrieved on 2026-10-11 notes UniProt explicitly annotates spontaneous dehydration of the reduced intermediate to aurachin B. This is a chemical conversion, not an additional AuaH enzymatic step. No new exact identifier or stereochemical assignment is made for the intermediate or aurachin B. Reviewed UniProtKB entry version 35, sequence version 1; adopted annotation, not an independently inspected primary experiment. UniProt cites DOI:10.1002/anie.201204138 for function.

Every edge carries its own citation; an uncited edge is refused by the corpus tests.

Elsewhere in the fleet

AntibioticMech — CHEBI:90888 (same structure, same inchikey)

Explore across X-Mech

AntibioticMech (aurachin C) ↗ MediaIngredientMech (CHEBI:90888) ↗ TaxonMech: Streptomyces sp. (NCBITaxon:1931) ↗ PathwayMech (mibig:BGC0002591) ↗

Open questions 1

curator-aurachin-c-auagh-scope — Which independently inspected primary experiments can resolve native constructs and formation of aurachin C, beyond its annotated conversion toward aurachin B?

Provenance

Source concept	Source	Version
BGC0002591	MIBIG	2
CHEBI:90888	CHEBI	3-star

This page is generated from data/natural_products/alkaloids/aurachin-c.yaml, which is generated from the committed inventories. Neither is edited by hand.