Terminal oxidases of cyanobacteria.

The respiratory chain of cyanobacteria appears to be branched rather than linear; furthermore, respiratory and photosynthetic electron-transfer chains co-exist in the thylakoid membrane and even share components. This review will focus on the three types of terminal respiratory oxidases identified so far on a genetic level in cyanobacteria: aa3-type cytochrome c oxidase, cytochrome bd-quinol oxidase and the alternative respiratory terminal oxidase. We summarize here their genetic, biochemical and biophysical characterization to date and discuss their interactions with electron donors as well as their physiological roles.