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Title | Atomic insights of an up and down conformation of the Acinetobacter baumannii F -ATPase subunit ε and deciphering the residues critical for ATP hydrolysis inhibition and ATP synthesis. |
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Journal, issue, pages | FASEB J, Vol. 37, Issue 7, Page e23040, Year 2023 |
Publish date | Jun 19, 2023 |
Authors | Wuan-Geok Saw / Khoa Cong Minh Le / Joon Shin / Jes Hui Min Kwek / Chui Fann Wong / Priya Ragunathan / Tuck Choy Fong / Volker Müller / Gerhard Grüber / |
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 ...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. |
External links | FASEB J / PubMed:37318822 |
Methods | EM (single particle) / NMR (solution) |
Resolution | 3.0 Å |
Structure data | EMDB-34066, PDB-7yry: PDB-8hgx: |
Chemicals | ChemComp-ATP: ChemComp-MG: ChemComp-ADP: ChemComp-PO4: |
Source |
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Keywords | HYDROLASE / F1-ATPase / Acinetobacter baumannii / ELECTRON TRANSPORT / F-ATP synthase / subunit eosilon / bioenergetics / Acinetobacter / baumannii |