| Type: | Conserved_site | Name: | Antenna complex, beta subunit, conserved site |
| Description: | 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 2polypeptides (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 beinvolved in binding the magnesium atom of a bacteriochlorophyll group. The beta-chains are characterised by a further histidine at the C-terminalextremity of the cytoplasmic domain, which is also thought to be involved in bacteriochlorophyll binding.This entry represents a conserved site in the beta subunit that includes the histidine residues thought to be involved in bacteriochlorophyll binding. | Short Name: | Antenna_beta_CS |
