Bioenergetics of Archaea: ATP Synthesis under Harsh Environmental Conditions

Abstract

Archaea are a heterogenous group of microorganisms that often thrive under harsh environmental conditions such as high temperatures, extreme pHs and high salinity. As other living cells, they use chemiosmotic mechanisms along with substrate level phosphorylation to conserve energy in form of ATP. Because some archaea are rooted close to the origin in the tree of life, these unusual mechanisms are considered to have developed very early in the history of life and, therefore, may represent first energy-conserving mechanisms. A key component in cellular bioenergetics is the ATP synthase. The enzyme from archaea represents a new class of ATPases, the A₁A₀ ATP synthases. They are composed of two domains that function as a pair of rotary motors connected by a central and peripheral stalk(s). The structure of the chemically-driven motor (A₁) was solved by small-angle X-ray scattering in solution, and the structure of the first A₁A₀ ATP synthases was obtained recently by single particle analyses. These studies revealed novel structural features such as a second peripheral stalk and a collar-like structure. In addition, the membrane-embedded electrically-driven motor (A₀) is very different in archaea with sometimes novel, exceptional subunit composition and coupling stoichiometries that may reflect the differences in energy-conserving mechanisms as well as adaptation to temperatures at or above 100°C.

Intracellular localization of membrane‐bound ATPases in the compartmentalized anammox bacterium ‘Candidatus Kuenenia stuttgartiensis’

“…F‐ATPase‐1 resembled most the typical F‐ATPase from E. coli but also the F‐ATPase from Acetobacterium woodii (Müller et al ., 2005). The K. stuttgartiensis transcriptome showed a high relative expression (ranging from 0.9–8.1) of all genes in the F‐ATPase‐1 gene cluster and in the proteome, peptides of six of the 11 genes were detected (Table 1).…”

A sodium ion‐dependent A1AO ATP synthase from the hyperthermophilic archaeon Pyrococcus furiosus

“…This hypothetical model is based on biochemical data summarized in Müller et al. [64,65]. Please note that the stoichiometry of the c subunits is unknown but is likely to be different in A 1 A O ATP synthases from different organisms [68].…”

The Structure of Subunit E of the Pyrococcus horikoshii OT3 A-ATP Synthase Gives Insight into the Elasticity of the Peripheral Stalk

“…4 Like the related bacterial F 1 F O ATP synthase (F-ATP synthase) (α 3 :β 3 :γ:δ:ɛ:a:b 2 :c x ), it possesses a water-soluble A 1 domain, containing the catalytic sites, and an integral membrane A O domain, involved in ion translocation. 5 ATP is synthesized or hydrolyzed on the A 1 headpiece, consisting of an A 3 :B 3 part, and the energy provided for or released during that process is transmitted to the membrane-bound A O sector. The energy coupling between the two active domains occurs via the so-called stalk and/or stators.…”