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Mol Cell. 2018 Mar 15;69(6):993-1004.e3. doi: 10.1016/j.molcel.2018.02.006. Epub 2018 Mar 8.

The 3.5-Å CryoEM Structure of Nanodisc-Reconstituted Yeast Vacuolar ATPase Vo Proton Channel.

Author information

1
Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
2
Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
3
Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
4
Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
5
Department of Bioengineering and James H. Clark Center, Stanford University, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA. Electronic address: wahc@stanford.edu.
6
Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA. Electronic address: wilkenss@upstate.edu.

Abstract

The molecular mechanism of transmembrane proton translocation in rotary motor ATPases is not fully understood. Here, we report the 3.5-Å resolution cryoEM structure of the lipid nanodisc-reconstituted Vo proton channel of the yeast vacuolar H+-ATPase, captured in a physiologically relevant, autoinhibited state. The resulting atomic model provides structural detail for the amino acids that constitute the proton pathway at the interface of the proteolipid ring and subunit a. Based on the structure and previous mutagenesis studies, we propose the chemical basis of transmembrane proton transport. Moreover, we discovered that the C terminus of the assembly factor Voa1 is an integral component of mature Vo. Voa1's C-terminal transmembrane α helix is bound inside the proteolipid ring, where it contributes to the stability of the complex. Our structure rationalizes possible mechanisms by which mutations in human Vo can result in disease phenotypes and may thus provide new avenues for therapeutic interventions.

KEYWORDS:

V(o) proton channel; V-ATPase assembly; Voa1; cryoEM; lipid nanodisc; membrane protein structure; proton pumping; reversible disassembly; vacuolar H(+)-ATPase

PMID:
29526695
PMCID:
PMC5893162
DOI:
10.1016/j.molcel.2018.02.006
[Indexed for MEDLINE]
Free PMC Article

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