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- Title
The ζ subunit of the F<sub>1</sub>F<sub>o</sub>-ATP synthase of α-proteobacteria controls rotation of the nanomotor with a different structure.
- Authors
Zarco-Zavala, Mariel; Morales-Ríos, Edgar; Mendoza-Hernández, Guillermo; Ramírez-Silva, Leticia; Pérez-Hernández, Gerardo; Garcia-Trejo, José J.
- Abstract
The ζ subunit is a novel natural inhibitor of the α-proteobacterial F1Fo-ATPase described origi- nally in Paracoccus denitrificans. To characterize the mechanism by which this subunit inhibits the F1F nanomotor, the ζ subunit of Paracoccus denitrificans (Pd-ζ) was analyzed by the combination of kinetic, biochemical, bioinformatic, proteomic, and structura approaches. The ζ subunit causes full inhibition of the sulfite-activated PdF1-ATPase with an apparent IC50 of 270 nM by a mechanism independent of the ε subtmit. The inhibitory region of the ζ subunit resides in the first 14 N-terminal residues of the protein, which protrude from the 4-α-helix bundle structure of the isolated g subtmit, as resolved by NMR. Cross-linking experiments show that the ζ subunit interacts with rotor (γ) and stator (α, β) subunits of the F1-ATPase indicating that the g subunit hinders rotation of the central stalk. In addition, a putatively regulatory nucleotide-binding site was found in the ζ subunit by isothermal titration calorimetry. Together, the data show that the subunit controls the rotation of F1Fo-ATPase by a mechanism reminiscent of, but different from, those described for mitochondrial IF1 and bacterial ε sub-units where the 4-α-helix bundle of g seems to work as an anchoring domain that orients the N-termin inhibitory domain to hinder rotation of the central stalk.
- Subjects
PARACOCCUS denitrificans; PROTEOBACTERIA; BIOINFORMATICS; MITOCHONDRIA; ADENOSINE triphosphatase
- Publication
FASEB Journal, 2014, Vol 28, Issue 5, p2146
- ISSN
0892-6638
- Publication type
Article
- DOI
10.1096/fj.13-241430