Respiratory Pathways in Archaea
Imke Schröder and Simon de Vries
from: Archaea: New Models for Prokaryotic Biology (Edited by: Paul Blum). Caister Academic Press, U.K. (2008)
Respiratory diversity allows archaea to adapt and thrive even in the most extreme places significantly impacting the geochemistry of this planet. This chapter will summarize the current advances in research on archaeal oxygen, nitrate and Fe(III) respiration. While much is known about the bioenergetics and biochemical properties of the enzymes involved in oxygen and nitrate respiration our understanding of the mechanisms of Fe(III) respiration in the archaea is in its infancy. Respiratory enzymes are greatly conserved amongst archaea and bacteria but archaeal enzymes and bioenergetics exhibit several features that may reflect early evolutionary variants or adaptations to extreme environments. Unique archaeal enzymes in oxygen respiration include the oxidase supercomplexes present in Sulfolobus species that allow for efficient electron transfer, and quinone linked N-oxide reductases with several cofactor modifications in Pyrobaculum species representing a simple electron transport chain. Thus, the archaeal respiratory repertoire diverges from bacterial energy-generating pathways and future discoveries of other archaea specific traits are likely read more ...