Akutsu H. Strategies for elucidation of the structure and function of the large membrane protein complex, F
oF
1-ATP synthase, by nuclear magnetic resonance.
Biophys Chem 2023;
296:106988. [PMID:
36898347 DOI:
10.1016/j.bpc.2023.106988]
[Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023]
Abstract
Nuclear magnetic resonance (NMR) investigation of large membrane proteins requires well-focused questions and critical techniques. Here, research strategies for FoF1-ATP synthase, a membrane-embedded molecular motor, are reviewed, focusing on the β-subunit of F1-ATPase and c-subunit ring of the enzyme. Segmental isotope-labeling provided 89% assignment of the main chain NMR signals of thermophilic Bacillus (T)F1β-monomer. Upon nucleotide binding to Lys164, Asp252 was shown to switch its hydrogen-bonding partner from Lys164 to Thr165, inducing an open-to-closed bend motion of TF1β-subunit. This drives the rotational catalysis. The c-ring structure determined by solid-state NMR showed that cGlu56 and cAsn23 of the active site took a hydrogen-bonded closed conformation in membranes. In 505 kDa TFoF1, the specifically isotope-labeled cGlu56 and cAsn23 provided well-resolved NMR signals, which revealed that 87% of the residue pairs took a deprotonated open conformation at the Foa-c subunit interface, whereas they were in the closed conformation in the lipid-enclosed region.
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