light-harvesting complex

GO:0030076 · Energy complex · Multiprotein complex · Proposed

A protein-pigment complex that may be closely or peripherally associated to photosynthetic reaction centers that participate in harvesting and transferring radiant energy to the reaction center. [GO:0030076]

Synonyms: antenna complex

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
photosynthetic antenna proteins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Pigment-binding protein subunits and non-pigment linker or scaffold polypeptides that organize photosynthetic antenna pigments for light absorption and excitation-energy transfer. `GO:0030076` GO defines a light-harvesting complex as a protein-pigment complex. `DOI:10.1146/annurev-biophys-062920-063657` Sui 2021 reviewed phycobiliprotein and linker-polypeptide organization in phycobilisome antennae. `DOI:10.1074/jbc.M804824200` Olsen et al. 2008 imaged LH2 antenna organization in Rhodobacter sphaeroides DPF2G intracytoplasmic membranes. `DOI:10.1038/ncomms12454` Nielsen et al. 2016 resolved the CsmA protein lattice of the chlorosome baseplate antenna complex.
photosynthetic antenna pigments	Small molecule	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Light-absorbing cofactors whose tuned excitation energies support radiant-energy capture and transfer to photosynthetic reaction centers. `GO:0030076` GO defines a light-harvesting complex as a pigment-containing protein complex. `DOI:10.1146/annurev-biophys-062920-063657` Sui 2021 reviewed phycobilin chromophores covalently attached to cyanobacterial phycobilisomes. `DOI:10.1074/jbc.M804824200` Olsen et al. 2008 mapped bacteriochlorophyll-containing LH2 complexes in Rhodobacter sphaeroides DPF2G intracytoplasmic membranes. `DOI:10.1038/ncomms12454` Nielsen et al. 2016 modeled bacteriochlorophyll a pigments bound inside the chlorosome CsmA baseplate.

Taxonomic distribution

NCBITaxon:1148 Synechocystis sp. PCC 6803 — COMMON: Cyanobacterial model whose phycobilisome rods and cores exemplify biliprotein light-harvesting complexes. [DOI:10.1038/s41467-021-25813-y]
NCBITaxon:1063 Cereibacter sphaeroides — COMMON: Purple photosynthetic bacterium whose native photosynthetic membranes contain LH2 as a major light-harvesting antenna. [DOI:10.1073/pnas.0407295102]
NCBITaxon:1097 Chlorobaculum tepidum — COMMON: Green sulfur bacterium whose chlorosome CsmA baseplate antenna complexes were resolved in situ. [DOI:10.1038/ncomms12454]

Canonical examples

NCBITaxon:1148 Synechocystis sp. PCC 6803 — Cyanobacterial phycobilisome model with cryo-EM structures in light-harvesting and photoprotected states. [DOI:10.1038/s41467-021-25813-y]
NCBITaxon:1063 Cereibacter sphaeroides — Purple-bacterial photosynthetic-membrane model with organized RC-LH1-PufX core domains, interspersed LH2 complexes, and some separate LH2 antenna domains. [DOI:10.1073/pnas.0407295102]
NCBITaxon:1097 Chlorobaculum tepidum — Green sulfur bacterium whose chlorosomes carry a CsmA bacteriochlorophyll a baseplate antenna complex. [DOI:10.1038/ncomms12454]

Functions

photosynthesis, light harvesting GO:0009765 — Light-harvesting complexes absorb radiant energy in photosynthetic antenna pigments and route the resulting excitation toward reaction-center complexes.
- GO:0030076 GO defines light-harvesting complexes by radiant-energy harvest and transfer to a reaction center.
- DOI:10.1146/annurev-biophys-062920-063657 Sui 2021 reviewed phycobilisome light capture and downhill excitation-energy transfer to photosystems.
- DOI:10.1038/ncomms12454 Nielsen et al. 2016 modeled excitation transfer through the CsmA baseplate toward downstream reaction centers.

Mechanism graphs

Antenna protein-pigment complexes transfer excitation to reaction centers (FUNCTION)

Photosynthetic antenna proteins assemble with photosynthetic antenna pigments into light-harvesting complexes that absorb radiant energy and transfer excitation toward photosynthetic reaction centers.

Subject	Predicate	Object	Evidence
photosynthetic antenna proteins	organize	photosynthetic antenna pigments	`DOI:10.1146/annurev-biophys-062920-063657` Sui 2021 reviewed phycobiliprotein-bound phycobilins and linker-mediated spectral tuning in phycobilisomes. `DOI:10.1038/ncomms12454` Nielsen et al. 2016 modeled bacteriochlorophyll a pigments arranged by CsmA baseplate subunits.
photosynthetic antenna proteins	assemble into	light-harvesting complex	`GO:0030076` GO defines a light-harvesting complex as a protein-pigment complex. `DOI:10.1038/ncomms12454` Nielsen et al. 2016 resolved CsmA apoproteins as the chlorosome baseplate antenna scaffold.
photosynthetic antenna pigments	are bound in	light-harvesting complex	`GO:0030076` GO defines a light-harvesting complex as a pigment-containing protein complex. `DOI:10.1146/annurev-biophys-062920-063657` Sui 2021 reviewed phycobilin chromophore attachment in phycobilisome antennae.
light-harvesting complex	transfers excitation energy to	photosynthetic reaction center	`GO:0030076` GO defines light-harvesting complexes by participation in radiant-energy transfer to the reaction center. `DOI:10.1073/pnas.0407295102` Frese et al. 2004 modeled native Rhodobacter sphaeroides photosynthetic membranes that contain RC-LH1-PufX complexes interspersed with LH2 antennae.
light-harvesting complex	contributes to	photosynthesis, light harvesting	`GO:0030076` GO defines light-harvesting complexes as cellular components that harvest radiant energy.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral grounding for antenna protein and pigment groups before splitting the generic component rows. This parent record spans biliprotein, bacteriochlorophyll and chlorophyll antenna systems; one broad protein-family or ChEBI accession would either be too narrow for the GO:0030076 parent or too broad to denote only light-harvesting constituents.
CURATION_TODO (OPEN): Curate LH2, RC-LH1 core, phycobilisome, chlorosome baseplate and other lineage-specific antenna architectures as child records rather than components of this generic GO parent. GO:0030076 covers several protein-pigment architectures with different subunits, pigments, membrane contexts and excitation paths; purple-bacterial chromatophores alone distinguish peripheral LH2 antennae from RC-LH1 reaction-center core antennae, so this parent record intentionally captures only the shared antenna boundary.

Evidence

GO:0030076 Gene Ontology cellular-component term for a light-harvesting complex.
GO:0032991 Gene Ontology places light-harvesting complexes under protein-containing complexes.
GO:0009765 Gene Ontology biological-process term for photosynthesis, light harvesting.
DOI:10.1146/annurev-biophys-062920-063657 Sui 2021, Structure of Phycobilisomes, Annual Review of Biophysics.
DOI:10.1038/s41467-021-25813-y Sauer et al. 2021, Structural insight into the mechanism of energy transfer in cyanobacterial phycobilisomes, Nature Communications.
DOI:10.1074/jbc.M804824200 Olsen et al. 2008, The Organization of LH2 Complexes in Membranes from Rhodobacter sphaeroides, Journal of Biological Chemistry.
DOI:10.1038/ncomms12454 Nielsen et al. 2016, In situ high-resolution structure of the baseplate antenna complex in Chlorobaculum tepidum, Nature Communications.
DOI:10.1007/s11120-013-9869-3 Orf and Blankenship 2013, Chlorosome antenna complexes from green photosynthetic bacteria, Photosynthesis Research.
DOI:10.1073/pnas.0407295102 Frese et al. 2004, The long-range organization of a native photosynthetic membrane, Proceedings of the National Academy of Sciences.

Curation history

2026-09-16T01:30:43Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-16T01:31:46Z codex · EXPANDED_RECORD — Added GO synonymy and parentage, label-only antenna apoprotein and pigment component groups, cyanobacterial, purple-bacterial and green-bacterial scope, photosynthetic light-harvesting function and evidence, a nonmechanistic excitation-transfer graph, and component and subtype curation TODOs.
2026-09-16T01:32:27Z codex · POLISH_GRAPH — Split the generic antenna apoprotein-pigment assembly edge so both component nodes connect directly to the GO:0030076 light-harvesting complex structure node.
2026-09-16T01:44:41Z codex · REVIEW_FIXES — Addressed PR #1047 review issues #1048 and #1049 by broadening the apoprotein component to antenna proteins and adding core LH1/RC-LH1 reaction-center antennae to the lineage-specific subtype boundary.
2026-09-21T17:38:10Z codex · REPLACED_UNREADABLE_EVIDENCE — #1251: Replaced unreadable Bahatyrova 2004 and Comayras 2005 purple-bacterial light-harvesting citations with readable Olsen 2008 and Frese 2004 support.

Source: data/structures/energy_complex/light_harvesting_complex.yaml