Chlorophyll (Chl)-containing light-harvesting complexes (LHCs) in chloropla
sts of plant and algal cells usually include an oxidized Chi (Chl b or c) i
n addition to Chl a. Oxidation of peripheral groups on the tetrapyrrole str
ucture increases the Lewis acid strength of the central Mg atom. We propose
that the resulting stronger coordination bonds between oxidized Chls and l
igands in LHC apoproteins (LHCPs) stabilize the initial intermediates and t
hus promote assembly of LHCs within the chloroplast envelope. (C) 2001 Fede
ration of European Biochemical Societies. Published by Elsevier Science B.V
. All rights reserved.