ribosome

GO:0005840 · Ribonucleoprotein · Ribonucleoprotein complex · Proposed

The ribonucleoprotein particle that translates mRNA into protein. The bacterial and archaeal 70S ribosome comprises a small (30S) subunit built on 16S rRNA, which decodes the mRNA, and a large (50S) subunit built on 23S and 5S rRNA, whose 23S rRNA catalyses peptide bond formation. This record details that 70S form and the functional core shared with the larger eukaryotic cytosolic 80S ribosome; it does not enumerate 80S-specific components. [GO:0005840]

Rendering of the cryo-EM structure of a Psychrobacter urativorans 70S ribosome in complex with the hibernation factors Balon and RaiA (PDB 8RD8). A model derived from the cryo-EM map, not a raw micrograph. CRYO_EM · *Psychrobacter urativorans* (`NCBITaxon:45610`) · Helena-Bueno, K., Rybak, M.Y., Gagnon, M.G., Hill, C.H., Melnikov, S.V.; CC0, via Wikimedia Commons · CC0 · source: WIKIMEDIA_COMMONS File:P. urativorans 70S ribosome with Balon and RaiA.jpg (M149208035) · `DOI:10.1038/s41586-024-07041-8`

Synonyms: 70S ribosome

Has part: small ribosomal subunit (GO:0015935); large ribosomal subunit (GO:0015934)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
16S rRNA (small-subunit rRNA)	Rna	part of	`SO:0000650`	rrs	1	ESSENTIAL	Structural core of the 30S subunit; carries the decoding centre that monitors codon–anticodon pairing. `DOI:10.1038/35030006` Wimberly et al. 2000 report the 3.05 Å structure of the Thermus thermophilus 30S subunit, with 16S rRNA forming the body, platform and head.
23S rRNA (large-subunit rRNA)	Rna	part of	`SO:0000651`	rrl	1	ESSENTIAL	Structural core of the 50S subunit; forms the peptidyl transferase centre. `DOI:10.1126/science.289.5481.920` Nissen et al. 2000 show the peptidyl transferase centre of the Haloarcula marismortui 50S subunit is composed entirely of RNA — the ribosome is a ribozyme.
5S rRNA	Rna	part of	`SO:0000652`	rrf	1	ESSENTIAL	Small RNA of the 50S central protuberance. `DOI:10.1126/science.289.5481.905` Ban et al. 2000 resolve 5S rRNA within the 2.4 Å structure of the H. marismortui large subunit.
small-subunit ribosomal proteins (21 proteins in Escherichia coli)	Protein	part of	Reviewed label only (reviewed name; no accession asserted)		~21 in Escherichia coli	CONDITIONAL	Stabilise 16S rRNA folding and form the functional 30S subunit. `DOI:10.1038/35030006` Wimberly et al. 2000 place 20 proteins in the T. thermophilus 30S structure, mostly on the solvent-exposed surface. `DOI:10.1128/MMBR.00013-07` Kaczanowska and Rydén-Aulin 2007 report 21 proteins in the E. coli 30S subunit and 33 proteins in the 50S subunit.
large-subunit ribosomal proteins (33 proteins in Escherichia coli)	Protein	part of	Reviewed label only (reviewed name; no accession asserted)		~33 in Escherichia coli	CONDITIONAL	Stabilise 23S/5S rRNA; bL12 stalk recruits translation GTPases. `DOI:10.1126/science.289.5481.905` Ban et al. 2000 describe the protein complement of the large subunit and its distribution over the rRNA surface. `DOI:10.1128/MMBR.00013-07` Kaczanowska and Rydén-Aulin 2007 report 21 proteins in the E. coli 30S subunit and 33 proteins in the 50S subunit. `DOI:10.1038/nature08403` Schmeing and Ramakrishnan 2009 review ribosomal-protein roles in translation.

Source composition assertions

30S small ribosomal subunit (ComplexPortal:CPX-3802)

Escherichia coli (strain K12) (NCBITaxon:83333) · Hetero22-mer · ECO:0005547 · retrieved 2026-08-30

Participant	Source type	Source name	Stoichiometry
`UniProtKB:P0AG63` — Small ribosomal subunit protein uS17	protein	rpsQ	1
`RNAcentral:URS00005CADE5_83333` — Ribosomal RNA 16S Escherichia coli	ribosomal rna	16s_rrna_ecoli	1
`UniProtKB:P02358` — Small ribosomal subunit protein bS6	protein	rpsF	1
`UniProtKB:P02359` — Small ribosomal subunit protein uS7	protein	rpsG	1
`UniProtKB:P0A7W7` — Small ribosomal subunit protein uS8	protein	rpsH	1
`UniProtKB:P0A7S9` — Small ribosomal subunit protein uS13	protein	rpsM	1
`UniProtKB:P0A7V0` — Small ribosomal subunit protein uS2	protein	rpsB	1
`UniProtKB:P0A7V8` — Small ribosomal subunit protein uS4	protein	rpsD	1
`UniProtKB:P0A7W1` — Small ribosomal subunit protein uS5	protein	rpsE	1
`UniProtKB:P0A7S3` — Small ribosomal subunit protein uS12	protein	rpsL	1
`UniProtKB:P0AG59` — Small ribosomal subunit protein uS14	protein	rpsN	1
`UniProtKB:P0A7U3` — Small ribosomal subunit protein uS19	protein	rpsS	1
`UniProtKB:P0A7U7` — Small ribosomal subunit protein bS20	protein	rpsT	1
`UniProtKB:P0A7R5` — Small ribosomal subunit protein uS10	protein	rpsJ	1
`UniProtKB:P0A7V3` — Small ribosomal subunit protein uS3	protein	rpsC	1
`UniProtKB:P0ADZ4` — Small ribosomal subunit protein uS15	protein	rpsO	1
`UniProtKB:P0A7X3` — Small ribosomal subunit protein uS9	protein	rpsI	1
`UniProtKB:P68679` — Small ribosomal subunit protein bS21	protein	rpsU	1
`UniProtKB:P0AG67` — Small ribosomal subunit protein bS1	protein	rpsA	1
`UniProtKB:P0A7T3` — Small ribosomal subunit protein bS16	protein	rpsP	1
`UniProtKB:P0A7R9` — Small ribosomal subunit protein uS11	protein	rpsK	1
`UniProtKB:P0A7T7` — Small ribosomal subunit protein bS18	protein	rpsR	1

Curator-scoped import: E. coli 30S subunit; part of, not equivalent to, the whole ribosome. Source evidence: inferred by curator. The accession was resolved through the Complex Portal accession endpoint; no equivalence xref was inferred.

50S large ribosomal subunit (ComplexPortal:CPX-3807)

Escherichia coli (strain K12) (NCBITaxon:83333) · Hetero39-mer · ECO:0005547 · retrieved 2026-08-30

Participant	Source type	Source name	Stoichiometry
`UniProtKB:P0A7Q6` — Large ribosomal subunit protein bL36A	protein	rpmJ	1
`UniProtKB:P0A7N4` — Large ribosomal subunit protein bL32	protein	rpmF	1
`UniProtKB:P0A7P5` — Large ribosomal subunit protein bL34	protein	rpmH	1
`UniProtKB:P0A7M9` — Large ribosomal subunit protein bL31	protein	rpmE	1
`UniProtKB:P0AG51` — Large ribosomal subunit protein uL30	protein	rpmD	1
`UniProtKB:P0A7Q1` — Large ribosomal subunit protein bL35	protein	rpmI	1
`RNAcentral:URS00005B2216_83333` — 23S ribosomal RNA	ribosomal rna	23s_ecoli	1
`RNAcentral:URS000002D309_83333` — 5S ribosomal RNA	ribosomal rna	5s_ecoli	1
`UniProtKB:P60438` — Large ribosomal subunit protein uL3	protein	rplC	1
`UniProtKB:P0C018` — Large ribosomal subunit protein uL18	protein	rplR	1
`UniProtKB:P61175` — Large ribosomal subunit protein uL22	protein	rplV	1
`UniProtKB:P0ADZ0` — Large ribosomal subunit protein uL23	protein	rplW	1
`UniProtKB:P0AG48` — Large ribosomal subunit protein bL21	protein	rplU	1
`UniProtKB:P0A7N9` — Large ribosomal subunit protein bL33	protein	rpmG	1
`UniProtKB:P02413` — Large ribosomal subunit protein uL15	protein	rplO	1
`UniProtKB:P0A7M2` — Large ribosomal subunit protein bL28	protein	rpmB	1
`UniProtKB:P60422` — Large ribosomal subunit protein uL2	protein	rplB	1
`UniProtKB:P0A7K2` — Large ribosomal subunit protein bL12	protein	rplL	4
`UniProtKB:P0A7L0` — Large ribosomal subunit protein uL1	protein	rplA	1
`UniProtKB:P0AA10` — Large ribosomal subunit protein uL13	protein	rplM	1
`UniProtKB:P0A7K6` — Large ribosomal subunit protein bL19	protein	rplS	1
`UniProtKB:P0AG44` — Large ribosomal subunit protein bL17	protein	rplQ	1
`UniProtKB:P0A7L3` — Large ribosomal subunit protein bL20	protein	rplT	1
`UniProtKB:P60723` — Large ribosomal subunit protein uL4	protein	rplD	1
`UniProtKB:P0ADY3` — Large ribosomal subunit protein uL14	protein	rplN	1
`UniProtKB:P62399` — Large ribosomal subunit protein uL5	protein	rplE	1
`UniProtKB:P0AG55` — Large ribosomal subunit protein uL6	protein	rplF	1
`UniProtKB:P0A7R1` — Large ribosomal subunit protein bL9	protein	rplI	1
`UniProtKB:P60624` — Large ribosomal subunit protein uL24	protein	rplX	1
`UniProtKB:P0A7M6` — Large ribosomal subunit protein uL29	protein	rpmC	1
`UniProtKB:P0A7J3` — Large ribosomal subunit protein uL10	protein	rplJ	1
`UniProtKB:P0A7L8` — Large ribosomal subunit protein bL27	protein	rpmA	1
`UniProtKB:P0A7J7` — Large ribosomal subunit protein uL11	protein	rplK	1
`UniProtKB:P0ADY7` — Large ribosomal subunit protein uL16	protein	rplP	1
`UniProtKB:P68919` — Large ribosomal subunit protein bL25	protein	rplY	1
`UniProtKB:P0A7N1` — Large ribosomal subunit protein bL31B	protein	ykgM	1

Curator-scoped import: E. coli 50S subunit; part of, not equivalent to, the whole ribosome. Source evidence: inferred by curator. The accession was resolved through the Complex Portal accession endpoint; no equivalence xref was inferred.

Taxonomic distribution

NCBITaxon:2 Bacteria — UNIVERSAL: 70S form. [DOI:10.1038/nature08403]
NCBITaxon:2157 Archaea — UNIVERSAL: 70S sedimentation but with additional proteins; the large-subunit structure of H. marismortui is the archetypal high-resolution model. [DOI:10.1126/science.289.5481.905]
NCBITaxon:2759 Eukaryota — UNIVERSAL: Cytosolic 80S ribosome; this record covers the bacterial/archaeal 70S form and the shared core. [DOI:10.1038/nature08403]

Canonical examples

NCBITaxon:274 Thermus thermophilus — Source of the first complete 70S crystal structure. [DOI:10.1126/science.1060089]
NCBITaxon:83333 Escherichia coli K-12 — The genetic and biochemical reference system for bacterial translation. [DOI:10.1038/nature08403]
NCBITaxon:45610 Psychrobacter urativorans — Source of the cryo-EM 70S ribosome complex shown in the hosted rendering. [DOI:10.1038/s41586-024-07041-8]

Functions

translation GO:0006412 — Template-directed synthesis of polypeptides from mRNA.
- DOI:10.1038/nature08403 Schmeing & Ramakrishnan 2009 review how ribosome structures explain decoding, peptidyl transfer and translocation.
peptidyltransferase activity GO:0000048 — Peptide bond formation catalysed by 23S rRNA in the large subunit.
- DOI:10.1126/science.289.5481.920 Nissen et al. 2000 locate the catalytic site entirely within 23S rRNA.

Physical properties

SEDIMENTATION_COEFFICIENT: 70 (bacterial ribosome (Svedberg units)) [DOI:10.1126/science.1060089]
DIAMETER: ~20 UO:0000018 (Escherichia coli 70S particle) [DOI:10.1128/MMBR.00013-07]
MOLECULAR_MASS: ~2500 UO:0000222 (Escherichia coli 70S) [DOI:10.1038/nature08403]

Mechanism graphs

How the ribosome makes a peptide bond and moves along the mRNA (FUNCTION)

Core elongation-cycle mechanism common to all ribosomes.

Subject	Predicate	Object	Evidence
small ribosomal subunit	decodes	mRNA codon	`DOI:10.1126/science.1060612` Ogle et al. 2001 show 16S rRNA bases A1492, A1493 and G530 flip out to read the minor groove of the codon–anticodon helix.
aminoacyl-tRNA	substrate of	peptidyltransferase activity	`DOI:10.1038/nature08403` Aminoacyl-tRNA in the A site donates its amino group to the peptidyl-tRNA ester in the P site.
23S rRNA peptidyl transferase centre	catalyses `RO:0002327`	peptidyltransferase activity	`DOI:10.1126/science.289.5481.920` Nissen et al. 2000, the ribozyme result.
elongation factor G	drives	ribosomal translocation	`DOI:10.1038/nature08403` Schmeing & Ramakrishnan 2009 summarise EF-G-driven translocation.
ribosomal translocation	occurs in `BFO:0000066`	ribosome	`DOI:10.1038/nature08403` Translocation is an intrinsic ribosomal motion accelerated by EF-G.

Discussions

CURATION_TODO (OPEN): Should each ribosomal protein family be its own component with an InterPro grounding, rather than the two paralogue-set components used here? Per-protein components are what ProteinTraitsMech can link to; the set-level components are a placeholder.

More images

Panel a: two raw cryo-EM micrographs of E. coli 70S ribosome particles on holey carbon grids, with and without a 2 nm continuous carbon layer, 50 nm scale bar. Panels b-d of the same figure are a processing flowchart, an FSC resolution curve and angular-distribution plots, not imaging data. CRYO_EM · *Escherichia coli K-12* (`NCBITaxon:83333`) · Simon A. Fromm, Kate M. O’Connor, Michael Purdy, Pramod R. Bhatt, Gary Loughran, John F. Atkins, Ahmad Jomaa, Simone Mattei; CC BY, via PubMed Central · CC_BY_4_0 · source: PMC PMC9968351.1 Fig1 · `DOI:10.1038/s41467-023-36742-3`

Evidence

DOI:10.1126/science.1060089 Yusupov et al. 2001 — 5.5 Å structure of the complete T. thermophilus 70S ribosome with mRNA and tRNAs.
DOI:10.1126/science.289.5481.905 Ban et al. 2000 — 2.4 Å structure of the H. marismortui large subunit.
DOI:10.1038/35030006 Wimberly et al. 2000 — structure of the T. thermophilus 30S subunit.

Curation history

2026-08-29T00:00:00Z claude · CREATED_RECORD — Drafted composition, distribution, functions and elongation-cycle mechanism graph from the cited structural literature. Not yet human-reviewed.
2026-08-29T01:00:00Z claude · FIX_REVIEW_FINDINGS — PR #1 review: removed unresolvable xref ComplexPortal:CPX-3802 (#2); molecular-mass unit UO:0000021 (gram) -> UO:0000222 (kilodalton) (#3); Ogle 2001 DOI corrected to 10.1126/science.1060612 (#4). Every CURIE and DOI in the record was resolved against OLS/Crossref.
2026-08-29T03:00:00Z claude · ADD_IMAGE — Added Commons CC0 rendering of PDB 8RD8 (P. urativorans 70S ribosome, cryo-EM, DOI:10.1038/s41586-024-07041-8); organism and citation verified via RCSB and Crossref. Added P. urativorans to taxonomic_distribution as the imaged organism.
2026-08-30T05:00:00Z claude · FIX_ID_LABEL_FINDINGS — Vendored id-label gate (#48): removed GO:0003735 from the two ribosomal-protein set components (a molecular-function term cannot ground a protein set); removed SO:0000651 from the peptidyl-transferase-centre node (a part, not the whole 23S rRNA); relabelled GO:0000048 uses to the canonical 'peptidyltransferase activity'.
2026-08-30T19:08:35Z fetch_commons_image · ADD_IMAGE — Updated Commons image File:P. urativorans 70S ribosome with Balon and RaiA.jpg (CC0, Psychrobacter urativorans); licence, attribution and taxon read from the Commons and Wikidata APIs at retrieval.
2026-08-30T19:11:14Z fetch_commons_image · ADD_IMAGE — Updated Commons image File:P. urativorans 70S ribosome with Balon and RaiA.jpg (CC0, Psychrobacter urativorans); licence, attribution and taxon read from the Commons and Wikidata APIs at retrieval.
2026-08-30T19:29:55Z codex · REVIEW_COMPOSITION_AND_MEASUREMENTS — Replaced inaccurate uS/bS and uL/bL protein ranges with evidence-supported E. coli subunit counts; corrected 'paralogue set' to heterogeneous protein families and marked those lineage-specific sets CONDITIONAL; made the record's 70S-focused component scope explicit; removed an image organism from clade-level taxonomic distribution; narrowed the T. thermophilus exemplar claim; and replaced GO as the unsupported 20 nm measurement source with a review reporting a 210 Å E. coli particle.
2026-08-30T19:38:35Z codex · REVIEW_RECORD_SCOPE — Made the 70S-focused component scope explicit, marked the E. coli-specific grouped protein sets CONDITIONAL in the all-domain ribosome record, and removed an image-only Psychrobacter taxon from clade-level taxonomic distribution.
2026-08-30T19:40:01Z codex · DOCUMENT_IMAGE_EXEMPLAR — Added Psychrobacter urativorans as a cited structural exemplar for the hosted cryo-EM rendering rather than treating one experiment as universal taxon presence.
2026-08-31T04:03:42Z complex_portal · ADD_EVIDENCE — Added taxon-specific composition ComplexPortal:CPX-3802 (22 participants); exact accession and taxon verified at import.
2026-08-31T04:03:47Z complex_portal · ADD_EVIDENCE — Added taxon-specific composition ComplexPortal:CPX-3807 (36 participants); exact accession and taxon verified at import.
2026-08-31T06:18:57Z claude · SET_COMPONENT_ROLE — component_role became required (#77) so the constituent/machinery distinction is machine-readable rather than prose. Set per component; ASSOCIATED_MACHINERY only where the protein acts on the already-assembled structure.
2026-09-03T00:27:03Z pmc_oa · ADD_IMAGE — Added PMC9968351.1 Fig1; version, CC licence, JATS figure identity and media md5 verified through the PMC OA S3 dataset.
2026-09-03T00:27:41Z claude · ADD_MICROGRAPH — #35: added a real cryo-EM micrograph of E. coli 70S ribosomes (PMC9968351 Fig. 1a, CC BY 4.0) alongside the existing PDB 8RD8 rendering, which is kept as the issue asks. The figure is multi-panel and only panel a is imaging data; the caption states that instead of letting the composite read as a micrograph. Taxon NCBITaxon:83333 was already a canonical example on the record.
2026-09-04T01:40:08Z codex · ENHANCE_CAUSAL_GRAPH — Added descriptions to the remaining ribosome elongation-cycle edges so every edge now states the substrate or translocation step it represents.
2026-10-05T00:17:06Z codex · CORRECTED_METADATA — Issue #2043: preserve 3 nonprotein Complex Portal source name(s) in source_name instead of gene_symbol; identities, labels, taxa, membership and stoichiometry unchanged.

Source: data/structures/ribonucleoprotein/ribosome.yaml