ATP synthases: structure, function and evolution of unique energy converters

Abstract

A-, F- and V-adenosine 5'-triphosphatases (ATPases) consist of a mosaic of globular structural units which serve as functional units. These ion-translocating ATPases are thought to use a common mechanism to couple energy of ATP hydrolysis to ion transport and thus create an electrochemical ion gradient across the membrane. In vitro, all of these large protein complexes are able to use an ion gradient and the associated membrane potential to synthesize ATP. A-/F-/V-type ATPases are composed of two distinct segments: a catalytic sector, A1/F1/V1, whose three-dimensional structural relationship will be reviewed, and the membrane-embedded sector, Ao/Fo/Vo, which functions in ion conduction. Recent studies on the molecular biology of the Ao/Fo/Vo domains revealed surprising findings about duplicated and triplicated versions of the proteolipid subunit and shed new light on the evolution of these ion pumps.

Transport mechanisms of diuresis in Malpighian tubules of insects

“…Originally found in vacuolar membranes of plants and animals, the V-type H + -ATPase has now been found in the plasma membrane of cells in invertebrates and vertebrates . As shown in Fig.·3C, the pump consists of two major complexes, a cytoplasmic V1 complex capable of catalyzing the hydrolysis of ATP, and a membrane-spanning V0 complex with the properties of a H + channel (Muller and Gruber, 2003). The reversible disassembly of the two complexes is thought of as one mechanism for regulating pump transport activity (Wieczorek et al, 2000).…”

Renal Vacuolar H+-ATPase

“…The regulation of these processes and the development of associated diseases caused by inherited or acquired states of vacuolar H ϩ -ATPase dysfunction will also be addressed. (370). Mitochondrial F 1 F 0 -ATPases and vacuolar H ϩ -ATPases share many structural features such as subunit composition, high degrees of subunit similarities based on amino acid sequences, and subunit arrangement (212,384).…”

Three-dimensional Organization of the Archaeal A1-ATPase from Methanosarcina mazei Gö1

“…(i) The ammonium sulfate-precipitated enzyme was resolved in 10 ml of TMDG buffer (50 mM Tris/HCl, pH 7.5, 5 mM MgSO 4 , 10% (w/v) glycerol, 1 mM 1,4-dithioerythritol) and dialyzed overnight against TMDG buffer using a 300-kDa Spectra/Por Dialysis Membrane (Spectrum Laboratories, Canada), in order to remove ammonium sulfate. (ii) The further isolation of protein was done by ion-exchange chromatography (Resource TM Q (6 ml), Amersham Biosciences) by using a step gradient with Buffer A (50 mM Tris/HCl, pH 7.5, 150 mM NaCl, 1 mM DTT) 1 and Buffer B (50 mM Tris/HCl, pH 7.5, 1000 mM NaCl, 1 mM DTT). ATPase-containing peaks were pooled, concentrated separately on Centriprep 50-kDa and Centricon 100-kDa concentrators (Millipore), and applied on a Sephacryl TM S-300 HR column (10/30, Amersham Biosciences).…”

“…Although it was speculated for some time, due to the lack of indepth information, that the ATP synthases of Archaea may be either F 1 F 0 -or V 1 V 0 -like enzymes, it is now clear that they evolved as a separate class of ATPases/ATP synthases, the A 1 A 0 -ATPase/synthases (1)(2)(3)(4). This class of enzymes is different from F 1 F 0 -or V 1 V 0 -ATPases by function, subunit composition, regulation, and structure (1).…”

“…Although it was speculated for some time, due to the lack of indepth information, that the ATP synthases of Archaea may be either F 1 F 0 -or V 1 V 0 -like enzymes, it is now clear that they evolved as a separate class of ATPases/ATP synthases, the A 1 A 0 -ATPase/synthases (1)(2)(3)(4). This class of enzymes is different from F 1 F 0 -or V 1 V 0 -ATPases by function, subunit composition, regulation, and structure (1). The A 1 A 0 -ATPase has at least nine subunits (A 3 :B 3 :C:D:E:F:H:I:K x ), but the actual subunit stoichiometry, especially regarding the proteolipid subunits K in AATPases, is different in various organisms (12,6,4 or, as suggested by genomic data, only 1 (5)).…”