myxochelin B

CHEBI:7061 EXACT SEEDED

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REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record.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 member of the class of benzamides obtained by formal condensation of the 1- and 6-amino groups of hexane-1,2,6-triamine with the carboxy groups from two molecules of 2,3-dihydroxybenzoic acid followed by reduction of the amide carbonyl at position 5 to a hydroxy group.

Structure

Standard InChIKey	QTARRKFUMCSVOF-LBPRGKRZSA-N
SMILES	C1=CC(=C(C(=C1)O)O)C(=O)NCCCC[C@@H](CN)NC(=O)C2=C(C(=CC=C2)O)O
Stereochemistry	fully defined
Cross-references	pubchem:10873133

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 nrps, 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
Stigmatella aurantiaca Sg a15 NCBITaxon:675526	SOURCE_ASSERTION	mibig:BGC0001345	PMID:11562468

Occurrences 0

None cited.

Biosynthetic gene clusters 1

Accession	Host	Locus evidence	Genome
mibig:BGC0001345	Stigmatella aurantiaca Sg a15 NCBITaxon:675526	CLUSTER_UNSTATED	genbank:AF299336.1

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.

Biosynthesis curated

Written by a curator with claim-level evidence on each step; not derived from a source. This is what the rest of the record exists to support.

Step	Enzyme	Substrate → product	Evidence
1	MxcE 2,3-DHBA-AMP ligase UniProtKB:Q9F638	ungrounded → ungrounded	DOI:10.1073/pnas.201167098
2	MxcF isochorismatase and aryl carrier protein UniProtKB:Q9F637	ungrounded → ungrounded	DOI:10.1073/pnas.201167098
3	MxcG peptide synthetase with reductase domain UniProtKB:Q9F636	ungrounded → ungrounded	DOI:10.1073/pnas.201167098
4	MxcL aldehyde aminotransferase UniProtKB:Q9F631	ungrounded → ungrounded	DOI:10.1021/ja8025278

Step 1: MxcE adenylates 2,3-dihydroxybenzoic acid for transfer to the MxcF aryl carrier protein; the carrier-protein thioester is left ungrounded as a pathway intermediate.

Step 2: MxcF supplies the aryl carrier protein that receives activated 2,3-DHBA from MxcE and presents it to MxcG; its isochorismatase module contributes to DHBA formation from chorismate.

Step 3: MxcG adenylates lysine, condenses two MxcF-delivered DHBA groups with lysine, and uses its reductase domain for two-electron release of the carrier-protein-bound thioester to a myxochelin aldehyde branch-point intermediate.

Step 4: MxcL transaminates the free myxochelin aldehyde intermediate to the primary amine branch product myxochelin B.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 8 nodes, 7 edges

Partial Stigmatella aurantiaca myxochelin B assembly graph for the MxcE/MxcF/MxcG nonribosomal peptide synthetase machinery and the MxcL aminotransferase branch.

Subject	Predicate	Object	Notes	Evidence
2,3-dihydroxybenzoic acid	is adenylated by	MxcE	MxcE adenylates DHBA before MxcF carrier-protein loading.	DOI:10.1073/pnas.201167098 https://www.uniprot.org/uniprotkb/Q9F638 reference DOI:10.1073/pnas.201167098 evidence type PRIMARY_EXPERIMENT notes Gaitatzis et al. expressed active MxcE, MxcF, and MxcG and reconstituted ATP-, lysine-, DHBA-, and NAD(P)H-dependent myxochelin assembly in vitro. reference https://www.uniprot.org/uniprotkb/Q9F638 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F638 resolves to the AF299336.1 mxcE gene product used for the Stigmatella myxochelin pathway.
MxcE	loads activated 2,3-DHBA onto	MxcF	The MxcF aryl carrier protein receives activated DHBA for delivery to MxcG.	DOI:10.1073/pnas.201167098 https://www.uniprot.org/uniprotkb/Q9F637 reference DOI:10.1073/pnas.201167098 evidence type PRIMARY_EXPERIMENT notes Gaitatzis et al. expressed active MxcE, MxcF, and MxcG and reconstituted ATP-, lysine-, DHBA-, and NAD(P)H-dependent myxochelin assembly in vitro. reference https://www.uniprot.org/uniprotkb/Q9F637 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F637 resolves to the AF299336.1 mxcF gene product used for the Stigmatella myxochelin pathway.
L-lysine	is adenylated by	MxcG	The adenylation domain of MxcG activates lysine.	DOI:10.1073/pnas.201167098 https://www.uniprot.org/uniprotkb/Q9F636 reference DOI:10.1073/pnas.201167098 evidence type PRIMARY_EXPERIMENT notes Gaitatzis et al. expressed active MxcE, MxcF, and MxcG and reconstituted ATP-, lysine-, DHBA-, and NAD(P)H-dependent myxochelin assembly in vitro. reference https://www.uniprot.org/uniprotkb/Q9F636 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F636 resolves to the AF299336.1 mxcG gene product used for the Stigmatella myxochelin pathway.
MxcF	delivers activated 2,3-DHBA to	MxcG	MxcG condenses two MxcF-delivered DHBA units with the two amino groups of lysine.	DOI:10.1073/pnas.201167098 https://www.uniprot.org/uniprotkb/Q9F636 reference DOI:10.1073/pnas.201167098 evidence type PRIMARY_EXPERIMENT notes Gaitatzis et al. expressed active MxcE, MxcF, and MxcG and reconstituted ATP-, lysine-, DHBA-, and NAD(P)H-dependent myxochelin assembly in vitro. reference https://www.uniprot.org/uniprotkb/Q9F636 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F636 resolves to the AF299336.1 mxcG gene product used for the Stigmatella myxochelin pathway.
MxcG	reductively releases	myxochelin aldehyde	The C-terminal reductase domain of MxcG releases a free aldehyde that can be reduced to myxochelin A or transaminated toward myxochelin B.	DOI:10.1021/ja8025278 https://www.uniprot.org/uniprotkb/Q9F636 reference DOI:10.1021/ja8025278 evidence type PRIMARY_EXPERIMENT notes Li et al. combined MxcG reductase-domain formation of the free aldehyde intermediate with MxcL transamination to reconstitute myxochelin B biosynthesis in vitro. reference https://www.uniprot.org/uniprotkb/Q9F636 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F636 resolves to the AF299336.1 mxcG gene product used for the Stigmatella myxochelin pathway.
myxochelin aldehyde	is transaminated by	MxcL	MxcL competes for the free aldehyde intermediate produced by two-electron MxcG reductase-domain release.	DOI:10.1021/ja8025278 https://www.uniprot.org/uniprotkb/Q9F631 reference DOI:10.1021/ja8025278 evidence type PRIMARY_EXPERIMENT notes Li et al. combined MxcG reductase-domain formation of the free aldehyde intermediate with MxcL transamination to reconstitute myxochelin B biosynthesis in vitro. reference https://www.uniprot.org/uniprotkb/Q9F631 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F631 resolves to the AF299336.1 mxcL gene product in the Stigmatella myxochelin gene cluster.
MxcL	forms	myxochelin B	MxcL transamination yields the myxochelin B primary amine.	DOI:10.1021/ja8025278 https://www.uniprot.org/uniprotkb/Q9F631 reference DOI:10.1021/ja8025278 evidence type PRIMARY_EXPERIMENT notes Li et al. combined MxcG reductase-domain formation of the free aldehyde intermediate with MxcL transamination to reconstitute myxochelin B biosynthesis in vitro. reference https://www.uniprot.org/uniprotkb/Q9F631 evidence type DATABASE_ASSERTION retrieved on 2026-09-28 notes UniProtKB:Q9F631 resolves to the AF299336.1 mxcL gene product in the Stigmatella myxochelin gene cluster.

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

Explore across X-Mech

AntibioticMech (myxochelin B) ↗ MediaIngredientMech (CHEBI:7061) ↗ TaxonMech: Stigmatella aurantiaca Sg a15 (NCBITaxon:675526) ↗ PathwayMech (mibig:BGC0001345) ↗

Provenance

Source concept	Source	Version
BGC0001345	MIBIG	5
CHEBI:7061	CHEBI	3-star

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