Rubisco rules fall; gene transfer triumphs.
The most common form of the CO2-fixing enzyme rubisco is a form I enzyme, heretofore found universally in oxygenic phototrophs (cyanobacteria and plastids) and widely in proteobacteria. Two groups, however (1-4), now report that in dinoflagellate plastids the usual form I rubisco has been replaced by the distantly related form II enzyme, known previously only from anaerobic proteobacteria. This raises the important question of how such an oxygen-sensitive rubisco could function in an aerobic organism. Moreover, the dinoflagellate rubisco has unusual molecular properties: it is encoded as a polyprotein, by nuclear (rather than plastid) genes, and these genes contain noncanonical spliceosomal introns. The nuclear location and alpha-proteobacterial affinity of dinoflagellate rubisco genes hint at a possible mitochondrial origin and highlight the extraordinary richness of lateral gene transfers, both between and within organisms, that have occurred during rubisco evolution.
Palmer
J D
JD
Department of Biology, Indiana University, Bloomington 47405, USA.
D000818:Animals; D004141:Dinoflagellida / Q000201:enzymology* / Q000235:genetics; D019143:Evolution, Molecular; D017125:Genes, Protozoan; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D012273:Ribulose-Bisphosphate Carboxylase