Insights into the evolution of the antenna domains of Type-I and Type-II photosynthetic reaction centres through homology modelling.
The (bacterio)chlorophylls of photosynthetic antenna and reaction centre complexes are bound to the protein via a fifth, axial ligand to the central magnesium atom. A number of the amino acids identified as providing such ligands are conserved between the large antenna of the cyanobacterial Type-I reaction centre and smaller antennas of the Type-I reaction centres of green sulphur bacteria and heliobacteria, and these numbers match closely the estimated number of antenna bacteriochlorophylls in the latter. The possible organisation of the antenna in the latter reaction centres is discussed, as is the mechanism by which the more pigment-rich antenna of the cyanobacterial reaction centre evolved. The homology modelling approach is also extended to the six-helix antenna proteins CP47 and CP43 associated with the Photosystem II reaction centre.
Fyfe
Paul K
PK
Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, UK.
Jones
Michael R
MR
Heathcote
Peter
P
D000595:Amino Acid Sequence; D000458:Cyanobacteria / Q000737:chemistry / Q000378:metabolism; D019143:Evolution, Molecular; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D045322:Photosynthetic Reaction Center Complex Proteins