sulfur globule
A bacterial sulfur storage inclusion that accumulates elemental sulfur from reduced sulfur compounds and packages it with sulfur-globule envelope proteins for temporary storage and later oxidation. [DOI:10.1159/000351335]
Synonyms: intracellular sulfur globule
Components
| Component | Type | Part of / acts on | Grounding | Genes | Stoichiometry | Essential | Role |
|---|---|---|---|---|---|---|---|
| elemental sulfur | Small molecule | part of | CHEBI:33403 | ESSENTIAL | Stored elemental sulfur that forms the globule core and is mobilized during subsequent sulfur oxidation.
| ||
| SgpA/SgpB sulfur globule envelope proteins | Protein | part of | Reviewed label only (reviewed name; no accession asserted) | sgpA, sgpB | CONDITIONAL | Hydrophobic envelope proteins that coat sulfur globules and are jointly required for normal globule formation.
| |
| SgpC sulfur globule envelope protein | Protein | part of | Reviewed label only (reviewed name; no accession asserted) | sgpC | CONDITIONAL | Small sulfur-globule envelope protein required for normal globule expansion in Allochromatium vinosum.
|
Taxonomic distribution
NCBITaxon:2Bacteria — VARIABLE: Intracellular sulfur globules occur in multiple sulfur-oxidizing bacterial groups but are absent from most bacteria. [DOI:10.1159/000351335]
Canonical examples
NCBITaxon:572477Allochromatium vinosum DSM 180 — Purple sulfur bacterium used for SgpA, SgpB and SgpC sulfur globule protein mutagenesis. [DOI:10.1007/s00203-004-0683-3]
Functions
- temporary elemental sulfur storage — Sulfur globules sequester elemental sulfur formed during reduced sulfur oxidation and retain it as an intracellular reserve for later oxidation.
DOI:10.1159/000351335Maki 2013 reviews intracellular sulfur globules as temporary sulfur reservoirs in sulfur-oxidizing bacteria.
Mechanism graphs
Sgp envelope proteins package stored sulfur (ASSEMBLY)
Elemental sulfur accumulates as a globule core while SgpA, SgpB and SgpC envelope proteins support normal sulfur globule formation and expansion.
| Subject | Predicate | Object | Evidence |
|---|---|---|---|
| SgpA/SgpB sulfur globule envelope proteins | form envelope around | elemental sulfur |
|
| SgpC sulfur globule envelope protein | supports expansion of | sulfur globule |
|
| elemental sulfur | forms core of | sulfur globule |
|
| sulfur globule | stores | stored elemental sulfur |
|
Discussions
- CURATION_TODO (OPEN): Resolve exact family groundings for bacterial SgpA/SgpB/SgpC sulfur-globule envelope proteins. Allochromatium vinosum Sgp proteins define the best-studied envelope, but sulfur globule envelopes vary across intracellular and extracellular sulfur-storing bacteria. A first record should not guess exact InterPro, Pfam or NCBIfam accessions without a focused homology pass.
Evidence
DOI:10.1159/000351335Maki 2013, Bacterial intracellular sulfur globules: structure and function, Journal of Molecular Microbiology and Biotechnology.DOI:10.1007/s00203-004-0683-3Prange et al. 2004, Characterization of the sulfur globule proteins of Allochromatium vinosum and mutational analysis of the sulfur globule protein genes, Archives of Microbiology.
Curation history
2026-09-10T09:05:46Zclaude · CREATED_RECORD — Scaffolded by scripts/new_record.py2026-09-10T09:06:15Zclaude · EXPANDED_RECORD — Added GO inclusion parentage, elemental sulfur and SgpA/SgpB/SgpC components, bacterial taxonomic scope, an Allochromatium vinosum canonical example, a temporary sulfur-storage function, record-level evidence, an Sgp envelope assembly graph and an envelope-protein grounding TODO.2026-09-10T09:08:27Zclaude · EDITED_RECORD — Changed CHEBI:33403 component and graph node labels from elemental sulfur core to the ChEBI canonical label elemental sulfur.2026-09-10T09:17:34Zclaude · EDITED_RECORD — Removed GO:0016234 parentage because the GO inclusion body term denotes aggregated proteins or other biopolymers, not elemental sulfur storage globules.