5HKK

Caldalaklibacillus thermarum F1-ATPase (wild type)

Summary for 5HKK

• Entry DOI: 10.2210/pdb5hkk/pdb
• Related: 2HLD 2JDI 5CDF 5DN6
• Descriptor: ATP synthase subunit alpha, ATP synthase subunit beta, ATP synthase gamma chain, ... (10 entities in total)
• Functional Keywords: hydrolase, f1-atpase, complex
• Biological source: Caldalkalibacillus thermarum TA2.A1; More
• Cellular location: Cell membrane ; Peripheral membrane protein : F5LA74 F5LA72 F5LA73 F5LA71
• Total number of polymer chains: 16
• Total formula weight: 732242.01

Authors

Ferguson, S.A.,Cook, G.M.,Montgomery, M.G.,Leslie, A.G.W.,Walker, J.E. (deposition date: 2016-01-14, release date: 2016-09-21, Last modification date: 2024-01-10)

Primary citation

Ferguson, S.A.,Cook, G.M.,Montgomery, M.G.,Leslie, A.G.,Walker, J.E.
Regulation of the thermoalkaliphilic F1-ATPase from Caldalkalibacillus thermarum.
Proc.Natl.Acad.Sci.USA, 113:10860-10865, 2016

PubMed Abstract: The crystal structure has been determined of the F1-catalytic domain of the F-ATPase from Caldalkalibacillus thermarum, which hydrolyzes adenosine triphosphate (ATP) poorly. It is very similar to those of active mitochondrial and bacterial F1-ATPases. In the F-ATPase from Geobacillus stearothermophilus, conformational changes in the ε-subunit are influenced by intracellular ATP concentration and membrane potential. When ATP is plentiful, the ε-subunit assumes a "down" state, with an ATP molecule bound to its two C-terminal α-helices; when ATP is scarce, the α-helices are proposed to inhibit ATP hydrolysis by assuming an "up" state, where the α-helices, devoid of ATP, enter the α3β3-catalytic region. However, in the Escherichia coli enzyme, there is no evidence that such ATP binding to the ε-subunit is mechanistically important for modulating the enzyme's hydrolytic activity. In the structure of the F1-ATPase from C. thermarum, ATP and a magnesium ion are bound to the α-helices in the down state. In a form with a mutated ε-subunit unable to bind ATP, the enzyme remains inactive and the ε-subunit is down. Therefore, neither the γ-subunit nor the regulatory ATP bound to the ε-subunit is involved in the inhibitory mechanism of this particular enzyme. The structure of the α3β3-catalytic domain is likewise closely similar to those of active F1-ATPases. However, although the βE-catalytic site is in the usual "open" conformation, it is occupied by the unique combination of an ADP molecule with no magnesium ion and a phosphate ion. These bound hydrolytic products are likely to be the basis of inhibition of ATP hydrolysis.

PubMed: 27621435
DOI: 10.1073/pnas.1612035113

Experimental method

X-RAY DIFFRACTION (3 Å)