Antenna complex, alpha/beta subunit (IPR000066)

Short name: Antenna_a/b

Overlapping homologous superfamilies

Domain relationships



The antenna complexes of photosynthetic bacteria function as light-harvesting systems that absorb light and transfer the excitation energy to the reaction centres. The antenna complexes usually comprise 2 polypeptides (alpha- and beta-chains), 2-3 bacteriochlorophyll molecules and some carotenoids [PMID: 1577009, PMID: 1460542]. The alpha- and beta-chains are small proteins of 40-70 residues. Each has an N-terminal hydrophilic cytoplasmic domain, a single transmembrane (TM) region, and a small C-terminal hydrophilic periplasmic domain. In both chains, the TM domain houses a conserved His residue, presumed to be involved in binding the magnesium atom of a bacteriochlorophyll group. The beta-chains are characterised by a further histidine at the C-terminal extremity of the cytoplasmic domain, which is also thought to be involved in bacteriochlorophyll binding.

GO terms

Biological Process

GO:0019684 photosynthesis, light reaction

Molecular Function

GO:0045156 electron transporter, transferring electrons within the cyclic electron transport pathway of photosynthesis activity

Cellular Component

GO:0016021 integral component of membrane
GO:0030077 plasma membrane light-harvesting complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.