Protein Domain : Light-harvesting complex IPR035889

Type	Homologous_superfamily
Description	Bacterial light-harvesting complexes are also known as the antenna complexes. This entry represents the membrane all-alpha fold found in the alpha- and beta-chains of the antenna complexes.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 [ , ].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.
Short Name	Light-harvesting_complex