casbene

CHEBI:17695 EXACT SEEDED antifungal

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REVIEWED records curator sign-off on identity, structure, filing class and producer claims; DEPRECATED retains a superseded or out-of-scope record.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 diterpene comprising bicyclo[12.1.0]pentadeca-2,6,10-triene having three methyl substituents located at the 3-, 7- and 11-positions as well as gem-dimethyl groups at the 15-position.

Structure

Standard InChIKey	ZJMVJDFTNPZVMB-QOCMWZQCSA-N
SMILES	C/C/1=C\CC/C(=C/C2C(C2(C)C)CC/C(=C/CC1)/C)/C
Stereochemistry	undefined stereocentres — the InChIKey does not distinguish this compound from its stereoisomers
Cross-references	pubchem:5280437

Filing pathway

Terpenoids — 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 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
Jatropha curcas NCBITaxon:180498	SOURCE_ASSERTION	mibig:BGC0002723	DOI:10.1105/tpc.114.129668

Occurrences 2

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
Ricinus communis NCBITaxon:3988	LOTUS	DOI:10.1016/0003-9861(85)90171-7
Ricinus communis NCBITaxon:3988	LOTUS	DOI:10.1104/PP.81.2.335

Biosynthetic gene clusters 1

Accession	Host	Locus evidence	Genome
mibig:BGC0002723	Jatropha curcas NCBITaxon:180498	CLUSTER_DEMONSTRATED	genbank:GPS_020388126.1

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	Ricinus communis casbene synthase UniProtKB:P59287	RHEA:14901	CHEBI:58756 → CHEBI:17695 + CHEBI:33019	DOI:10.1006/abbi.1996.0559

Step 1: Ricinus communis casbene synthase cyclizes (2E,6E,10E)-geranylgeranyl diphosphate to casbene. The seeded BGC0002723 locus is from Jatropha curcas and carries NP_001292945.1 and XP_012066853.1, so it is not used here as exact UniProtKB:P59287 locus evidence.

Mechanism & Biosynthesis Overview

Causal graph — biosynthesis 3 nodes, 2 edges

Partial Ricinus communis casbene biosynthesis graph for casbene-synthase-catalyzed geranylgeranyl-diphosphate cyclization.

Subject	Predicate	Object	Notes	Evidence
(2E,6E,10E)-geranylgeranyl diphosphate	is cyclized by	Ricinus communis casbene synthase	Ricinus casbene synthase cyclizes geranylgeranyl diphosphate in the committed casbene-forming terpene synthase reaction.	DOI:10.1006/abbi.1996.0559 DOI:10.1073/pnas.91.18.8497 https://www.uniprot.org/uniprotkb/P59287 https://ftp.expasy.org/databases/rhea/tsv/rhea2uniprot_sprot.tsv reference DOI:10.1006/abbi.1996.0559 evidence type PRIMARY_EXPERIMENT snippet Casbene synthase catalyzes the cyclization of geranylgeranyl diphosphate (2) to casbene (1) notes Hill et al. expressed Ricinus communis casbene synthase in E. coli and characterized the recombinant enzyme by kinetic and product analysis. reference DOI:10.1073/pnas.91.18.8497 evidence type PRIMARY_EXPERIMENT snippet A near-full-length casbene synthase cDNA clone, pCS7, was isolated notes Mau and West cloned the Ricinus communis casbene synthase cDNA as GenBank L32134, and its open reading frame encodes the same 601 aa length as reviewed UniProtKB:P59287. reference https://www.uniprot.org/uniprotkb/P59287 evidence type DATABASE_ASSERTION snippet Catalyzes the cyclization of geranylgeranyl diphosphate to casbene retrieved on 2026-09-30 notes Reviewed UniProtKB:P59287 is the 601 aa Ricinus communis chloroplastic casbene synthase, cross-references the L32134 mRNA and the EQ973781 genomic protein EEF48743.1, and annotates RHEA:14901. reference https://ftp.expasy.org/databases/rhea/tsv/rhea2uniprot_sprot.tsv evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes The Rhea Swiss-Prot mapping links RHEA:14901 to UniProtKB:P59287.
Ricinus communis casbene synthase	forms	casbene	The Ricinus casbene synthase reaction forms the diterpene hydrocarbon casbene and diphosphate from geranylgeranyl diphosphate.	DOI:10.1006/abbi.1996.0559 DOI:10.1073/pnas.91.18.8497 https://www.uniprot.org/uniprotkb/P59287 https://ftp.expasy.org/databases/rhea/tsv/rhea2uniprot_sprot.tsv reference DOI:10.1006/abbi.1996.0559 evidence type PRIMARY_EXPERIMENT snippet Casbene synthase catalyzes the cyclization of geranylgeranyl diphosphate (2) to casbene (1) notes Hill et al. expressed Ricinus communis casbene synthase in E. coli and characterized the recombinant enzyme by kinetic and product analysis. reference DOI:10.1073/pnas.91.18.8497 evidence type PRIMARY_EXPERIMENT snippet A near-full-length casbene synthase cDNA clone, pCS7, was isolated notes Mau and West cloned the Ricinus communis casbene synthase cDNA as GenBank L32134, and its open reading frame encodes the same 601 aa length as reviewed UniProtKB:P59287. reference https://www.uniprot.org/uniprotkb/P59287 evidence type DATABASE_ASSERTION snippet Catalyzes the cyclization of geranylgeranyl diphosphate to casbene retrieved on 2026-09-30 notes Reviewed UniProtKB:P59287 is the 601 aa Ricinus communis chloroplastic casbene synthase, cross-references the L32134 mRNA and the EQ973781 genomic protein EEF48743.1, and annotates RHEA:14901. reference https://ftp.expasy.org/databases/rhea/tsv/rhea2uniprot_sprot.tsv evidence type DATABASE_ASSERTION retrieved on 2026-09-30 notes The Rhea Swiss-Prot mapping links RHEA:14901 to UniProtKB:P59287.

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

Elsewhere in the fleet

AntibioticMech — CHEBI:17695 (same structure, same inchikey)

Explore across X-Mech

AntibioticMech (casbene) ↗ MediaIngredientMech (CHEBI:17695) ↗ TaxonMech: Jatropha curcas (NCBITaxon:180498) ↗ PathwayMech (mibig:BGC0002723) ↗

Provenance

Source concept	Source	Version
BGC0002723	MIBIG	2
CHEBI:17695	CHEBI	3-star

This page is generated from data/natural_products/terpenoids/casbene.yaml, which is generated from the committed inventories. Neither is edited by hand.