Protein disulfide oxidoreductases and the evolution of thermophily: was the last common ancestor a heat-loving microbe?
Protein disulfide oxidoreductases (PDOs) are redox enzymes that catalyze dithiol-disulfide exchange reactions. Their sequences and structure reveal the presence of two thioredoxin fold units, each of which is endowed with a catalytic site CXXC motif. PDOs are the outcome of an ancient gene duplication event. They have been described in a number of thermophilic and hyperthermophilic species, where they play a critical role in the structural stabilization of intracellular proteins. PDOs are homologous to both the N-terminal domain of the bacterial alkyl hydroperoxide reductase (AhpF) and to the eukaryotic protein disulfide isomerase (PDI). Phylogenetic analysis of PDOs suggests that they first evolved in the crenarchaeota, spreading from them into the Bacteria via the euryarchaeota. These results imply that the last common ancestor (LCA) of all extant living beings lacked a PDO and argue, albeit weakly, against a thermophilic LCA.
Becerra
Arturo
A
Facultad de Ciencias, UNAM, Apdo Postal 70-407, Cd Universitaria, 04510, Mexico, DF, Mexico.
Delaye
Luis
L
Lazcano
Antonio
A
Orgel
Leslie E
LE
D000220:Adaptation, Biological / Q000235:genetics*; D000595:Amino Acid Sequence; D001105:Archaea / Q000235:genetics; D001419:Bacteria / Q000235:genetics; D019143:Evolution, Molecular; D005658:Fungi / Q000235:genetics; D049810:Genetic Speciation; D006358:Hot Temperature; D008954:Models, Biological; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
D009247:NADH, NADPH Oxidoreductases; C113416:protein disulfide oxidoreductase, P. furiosus