microcin J25

naturalproductmech:mibig-c68748ca1b MINTED SEEDED

Grounding review: No 3-star ChEBI entry shares this structure, so the record keeps a content-hashed identifier.

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REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record.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.

Structure

Standard InChIKey	FRJVEVHOMWPHHN-UHFFFAOYSA-N
SMILES	CCC(C)C(C(=O)NCC(=O)NC(C(C)O)C(=O)N1CCCC1C(=O)NC(C(C)CC)C(=O)NC(CO)C(=O)NC(CC2=CC=CC=C2)C(=O)NC(CC3=CC=C(C=C3)O)C(=O)NCC(=O)O)NC(=O)CNC(=O)C(C(C)C)NC(=O)C(CC4=CC=CC=C4)NC(=O)C(CC5=CC=C(C=C5)O)NC(=O)C6CCC(=O)NCC(=O)NCC(=O)NC(C(=O)NCC(=O)NC(C(=O)NC(C(=O)N7CCCC7C(=O)N6)C(C)C)CC8=CN=CN8)C
Stereochemistry	undefined stereocentres — the InChIKey does not distinguish this compound from its stereoisomers
Cross-references	pubchem:57397977, npatlas:NPA05946

Filing pathway

Amino acids and peptides — 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 ribosomal, 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
Escherichia coli AY25 NCBITaxon:562	SOURCE_ASSERTION	mibig:BGC0000581	DOI:10.1128/jb.178.12.3661-3663.1996

Occurrences 0

None cited.

Biosynthetic gene clusters 1

Accession	Host	Locus evidence	Genome
mibig:BGC0000581	Escherichia coli AY25 NCBITaxon:562	CLUSTER_DEMONSTRATED	genbank:AF061787.1

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	Reaction	Substrate → product	Evidence
1	McjB UniProtKB:Q9X2V8		UniProtKB:Q9X2V7 → ungrounded	DOI:10.1002/cbic.201200016
2	McjC UniProtKB:Q9X2V9		ungrounded → naturalproductmech:mibig-c68748ca1b	DOI:10.1002/cbic.201200016

Step 1: Leader cleavage in coupled McjB/McjC maturation of microcin J25. McjB removes the 37-residue McjA leader in the ATP-dependent reaction system. McjC is also required; the core intermediate is not assigned a chemical identifier.

Step 2: ATP-dependent macrolactam formation links the core N-terminal Gly1 amine to the Glu8 side-chain carboxyl group during lasso maturation. McjB is also required. The two numbered steps describe processing chemistry, not independently reconstituted enzymes or a freely released core intermediate. Protein grounding uses corrected CAJ40934.1, not the discrepant AAD28496.1 sequence.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 7 nodes, 8 edges

Coupled E. coli AY25 McjA precursor processing by McjB and McjC. Both enzymes are required for maturation; a physical complex is suggested, not asserted as established. The product is the seeded microcin J25 structure with stereochemistry incompletely specified in its source SMILES.

Subject	Predicate	Object	Evidence
McjA full-length precursor	is substrate for	McjA leader cleavage	DOI:10.1002/cbic.201200016 https://www.uniprot.org/uniprotkb/Q9X2V7 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes The McjA precursor undergoes proteolytic processing during McjB/McjC maturation. reference https://www.uniprot.org/uniprotkb/Q9X2V7 evidence type DATABASE_ASSERTION retrieved on 2026-10-03 notes The 58-residue E. coli AY25 McjA precursor matches GenPept AAD28494.1. Residues 1-37 form the leader and 38-58 the 21-residue core. The mature Gly1-Glu8 cross-link corresponds to precursor residues 38 and 45; the full-length UniProt accession here denotes the precursor, not the mature compound.
McjB leader peptidase	catalyzes	McjA leader cleavage	DOI:10.1002/cbic.201200016 https://www.uniprot.org/uniprotkb/Q9X2V8 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes McjB provides the proteolytic activity in the coupled maturation assay; this does not assert McjB acts alone. reference https://www.uniprot.org/uniprotkb/Q9X2V8 evidence type DATABASE_ASSERTION retrieved on 2026-10-03 notes E. coli AY25 mcjB; its 208-residue sequence exactly matches GenPept AAD28495.1 from AF061787.1, the sequence underlying MIBiG BGC0000581.
McjC lactam synthetase	is required for	McjA leader cleavage	DOI:10.1002/cbic.201200016 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes McjC is required for McjB-dependent processing under the reported assay conditions; this edge denotes functional dependence, not cleavage by McjC. snippet The two enzymes were functionally interdependent
McjA leader cleavage	produces	Cleaved McjA core intermediate	DOI:10.1002/cbic.201200016 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes Intermediate detection assigns leader removal before ring closure. The node does not assert release of a freely diffusible core peptide.
Cleaved McjA core intermediate	is substrate for	Gly1-Glu8 macrolactam formation	DOI:10.1002/cbic.201200016 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes Ring closure follows precursor cleavage within the coupled maturation system.
McjC lactam synthetase	catalyzes	Gly1-Glu8 macrolactam formation	DOI:10.1002/cbic.201200016 https://www.uniprot.org/uniprotkb/Q9X2V9 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes McjC supplies lactam-synthetase activity in the presence of McjB. reference https://www.uniprot.org/uniprotkb/Q9X2V9 evidence type DATABASE_ASSERTION retrieved on 2026-10-03 notes E. coli AY25 McjC is represented by the corrected 513-residue sequence, exactly matching CAJ40934.1 from AM116873.1/pTUC202. UniProt links this sequence to Duquesne et al. (PMID:17656316). Its sequence caution identifies the legacy 442-residue AAD28496.1 in AF061787.1/MIBiG BGC0000581 as discrepant; these two protein sequences are not treated as identical.
McjB leader peptidase	is required for	Gly1-Glu8 macrolactam formation	DOI:10.1002/cbic.201200016 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes McjB and McjC are functionally interdependent in the reported assays; this edge does not assign the amide-bond-forming chemistry to McjB.
Gly1-Glu8 macrolactam formation	produces	microcin J25	DOI:10.1002/cbic.201200016 reference DOI:10.1002/cbic.201200016 evidence type PRIMARY_EXPERIMENT notes The wild-type precursor yields mature microcin J25. Branched-cyclic variants from mutated precursors are not equated to this compound.

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

Explore across X-Mech

AntibioticMech (microcin J25) ↗ MediaIngredientMech (naturalproductmech:mibig-c68748ca1b) ↗ TaxonMech: Escherichia coli AY25 (NCBITaxon:562) ↗ PathwayMech (mibig:BGC0000581) ↗

Provenance

Source concept	Source	Version
BGC0000581	MIBIG	6

This page is generated from data/natural_products/amino_acids_and_peptides/microcin-j25.yaml, which is generated from the committed inventories. Neither is edited by hand.