Molecular Evolution of Cytochrome bd Oxidases across Proteobacterial Genomes

choi, frederick. ds;

This work is aimed to resolve the complex molecular evolution of cytochrome bd ubiquinol oxidase, a nearly ubiquitous bacterial enzyme that is involved in redox balance and bioenergetics. Previous studies have created an unclear picture of bd oxidases phylogenesis without considering the existence of diverse types of bd oxidases. Integrated approaches of genomic and protein analysis focused on proteo bacteria have generated a molecular classification of diverse types of bd oxidases,which produces a new scenario for interpreting the irevolution. A duplication of the original gene cluster of bdoxidase might have occurred intheancestors of extant a-proteobacteria of the Rhodospirillales order, such as Acidocella, from which the bd-I type of the oxidase might have diffused too the r proteo bacterial lineages. Incontrast, the Cyanide-Insensitive Oxidasety pemay have differentiated into recognizable subtypes after another gene cluster duplication. These subtypes are wides pread in the geno mesofa-,b-,and g-proteo bacteria,with occasional instances of lateral gene transfer. In resolving the evolutionary pattern of proteo bacterial b doxidases, this work sheds new light on the basal taxa of a-proteobacteria from which the g-proteobacterial lineage probably emerged