Gwm. Vanderstaay et al., THE 38 KDA CHLOROPHYLL-A CHLOROPHYLL-B PROTEIN OF THE PROKARYOTE PROCHLOROTHRIX-HOLLANDICA IS ENCODED BY A DIVERGENT PCB GENE/, Plant molecular biology, 36(5), 1998, pp. 709-716
The chlorophyll (Chi) a/b proteins of the photosynthetic prokaryotes a
ppear to have evolved by gene duplication and divergence of the core C
hi a antenna family, which also includes CP43 and CP47 and the iron-st
ress induced Chi a-binding IsiA proteins. We show here that Prochlorot
hrix hollandica has a cluster of three pcb (prochlorophyte chlorophyll
b) genes which are co-transcribed. The major antenna polypeptides of
32 and 38 kDa are encoded by pcbA and pcbC respectively. The pcbC gene
is significantly divergent from the other two and may have originated
by a gene duplication independent of the one that led to isiA and the
other prochlorophyte pcb genes. The distant relatedness of the three
prochlorophyte genera implies that not only the ability to make Chl b
and use it for light-harvesting arose independently in the three linea
ges, but also that the pcb genes may have arisen as the result of inde
pendent gene duplications in each lineage.