Origin and evolution of transmembrane Chl-binding proteins: hydrophobic cluster analysis suggests a common one-helix ancestor for prokaryotic (Pcb) and eukaryotic (LHC) antenna protein superfamilies

All chlorophyll (Chl)-binding proteins constituting the photosynthetic apparatus of both prokaryotes and eukaryotes possess hydrophobic domains, corresponding to membrane-spanning alpha-helices (MSHs). Hydrophobic cluster analysis of representative members of the different Ch1 protein superfamilies revealed that all Ch1 proteins except the five-helix reaction center II proteins and the small subunits of photosystern I possess related domains. As a major conclusion, we found that the eukaryotic antennae likely share a common precursor with the prokaryotic Chi alb antennae from Chl-b-containing oxyphotobacteria. From these data, we propose a global scheme for the evolution of these proteins from a one-MSH ancestor. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.