8HGX

NMR solution structure of subunit epsilon of the Acinetobacter baumannii F-ATP synthase

Summary for 8HGX

• Entry DOI: 10.2210/pdb8hgx/pdb
• Descriptor: ATP synthase epsilon chain (1 entity in total)
• Functional Keywords: f-atp synthase, subunit eosilon, bioenergetics, acinetobacter, baumannii, electron transport
• Biological source: Acinetobacter baumannii
• Total number of polymer chains: 1
• Total formula weight: 15511.76

Authors

Shin, J.,Grueber, G. (deposition date: 2022-11-15, release date: 2023-11-22, Last modification date: 2024-06-12)

Primary citation

Saw, W.G.,Le, K.C.M.,Shin, J.,Kwek, J.H.M.,Wong, C.F.,Ragunathan, P.,Fong, T.C.,Muller, V.,Gruber, G.
Atomic insights of an up and down conformation of the Acinetobacter baumannii F 1 -ATPase subunit epsilon and deciphering the residues critical for ATP hydrolysis inhibition and ATP synthesis.
Faseb J., 37:e23040-e23040, 2023

PubMed Abstract: The Acinetobacter baumannii F F -ATP synthase (α :β :γ:δ:ε:a:b :c ), which is essential for this strictly respiratory opportunistic human pathogen, is incapable of ATP-driven proton translocation due to its latent ATPase activity. Here, we generated and purified the first recombinant A. baumannii F -ATPase (AbF -ATPase) composed of subunits α :β :γ:ε, showing latent ATP hydrolysis. A 3.0 Å cryo-electron microscopy structure visualizes the architecture and regulatory element of this enzyme, in which the C-terminal domain of subunit ε (Abε) is present in an extended position. An ε-free AbF -ɑβγ complex generated showed a 21.5-fold ATP hydrolysis increase, demonstrating that Abε is the major regulator of AbF -ATPase's latent ATP hydrolysis. The recombinant system enabled mutational studies of single amino acid substitutions within Abε or its interacting subunits β and γ, respectively, as well as C-terminal truncated mutants of Abε, providing a detailed picture of Abε's main element for the self-inhibition mechanism of ATP hydrolysis. Using a heterologous expression system, the importance of Abε's C-terminus in ATP synthesis of inverted membrane vesicles, including AbF F -ATP synthases, has been explored. In addition, we are presenting the first NMR solution structure of the compact form of Abε, revealing interaction of its N-terminal β-barrel and C-terminal ɑ-hairpin domain. A double mutant of Abε highlights critical residues for Abε's domain-domain formation which is important also for AbF -ATPase's stability. Abε does not bind MgATP, which is described to regulate the up and down movements in other bacterial counterparts. The data are compared to regulatory elements of F -ATPases in bacteria, chloroplasts, and mitochondria to prevent wasting of ATP.

PubMed: 37318822
DOI: 10.1096/fj.202300175RR

Experimental method

SOLUTION NMR