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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] [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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Affiliation(s)
- Hideo Akutsu
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan; Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama 230-0045, Japan.
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2
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Cell-free synthesis of amyloid fibrils with infectious properties and amenable to sub-milligram magic-angle spinning NMR analysis. Commun Biol 2022; 5:1202. [DOI: 10.1038/s42003-022-04175-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
AbstractStructural investigations of amyloid fibrils often rely on heterologous bacterial overexpression of the protein of interest. Due to their inherent hydrophobicity and tendency to aggregate as inclusion bodies, many amyloid proteins are challenging to express in bacterial systems. Cell-free protein expression is a promising alternative to classical bacterial expression to produce hydrophobic proteins and introduce NMR-active isotopes that can improve and speed up the NMR analysis. Here we implement the cell-free synthesis of the functional amyloid prion HET-s(218-289). We present an interesting case where HET-s(218-289) directly assembles into infectious fibril in the cell-free expression mixture without the requirement of denaturation procedures and purification. By introducing tailored 13C and 15N isotopes or CF3 and 13CH2F labels at strategic amino-acid positions, we demonstrate that cell-free synthesized amyloid fibrils are readily amenable to high-resolution magic-angle spinning NMR at sub-milligram quantity.
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Todokoro Y, Kang SJ, Suzuki T, Ikegami T, Kainosho M, Yoshida M, Fujiwara T, Akutsu H. Chemical Conformation of the Essential Glutamate Site of the c-Ring within Thermophilic Bacillus F oF 1-ATP Synthase Determined by Solid-State NMR Based on its Isolated c-Ring Structure. J Am Chem Soc 2022; 144:14132-14139. [PMID: 35905443 DOI: 10.1021/jacs.2c03580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proton translocation through the membrane-embedded Fo component of F-type ATP synthase (FoF1) is facilitated by the rotation of the Fo c-subunit ring (c-ring), carrying protons at essential acidic amino acid residues. Cryo-electron microscopy (Cryo-EM) structures of FoF1 suggest a unique proton translocation mechanism. To elucidate it based on the chemical conformation of the essential acidic residues of the c-ring in FoF1, we determined the structure of the isolated thermophilic Bacillus Fo (tFo) c-ring, consisting of 10 subunits, in membranes by solid-state NMR. This structure contains a distinct proton-locking conformation, wherein Asn23 (cN23) CγO and Glu56 (cE56) CδOH form a hydrogen bond in a closed form. We introduced stereo-array-isotope-labeled (SAIL) Glu and Asn into the tFoc-ring to clarify the chemical conformation of these residues in tFoF1-ATP synthase (tFoF1). Two well-separated 13C signals could be detected for cN23 and cE56 in a 505 kDa membrane protein complex, respectively, thereby suggesting the presence of two distinct chemical conformations. Based on the signal intensity and structure of the tFoc-ring and tFoF1, six pairs of cN23 and cE56 surrounded by membrane lipids take the closed form, whereas the other four in the a-c interface employ the deprotonated open form at a proportion of 87%. This indicates that the a-c interface is highly hydrophilic. The pKa values of the four cE56 residues in the a-c interface were estimated from the cN23 signal intensity in the open and closed forms and distribution of polar residues around each cE56. The results favor a rotation of the c-ring for ATP synthesis.
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Affiliation(s)
- Yasuto Todokoro
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan.,Technical Support Division, School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka 560-0043, Japan
| | - Su-Jin Kang
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan.,Department of Biophysics and Chemical Biology, Seoul National University, Gwanak-Gu, Seoul 151-742, Republic of Korea.,College of Pharmacy, Dongduk Women's University, Seoul 02748, Republic of Korea
| | - Toshiharu Suzuki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama 226-0026, Japan
| | - Takahisa Ikegami
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Masatsune Kainosho
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
| | - Masasuke Yoshida
- Department of Molecular Bioscience, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto 603-8555, Japan
| | - Toshimichi Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan
| | - Hideo Akutsu
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan.,Department of Biophysics and Chemical Biology, Seoul National University, Gwanak-Gu, Seoul 151-742, Republic of Korea.,Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama 230-0045, Japan
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Krah A, Marzinek JK, Bond PJ. Characterizing the Hydration Properties of Proton Binding Sites in the ATP Synthase c-Rings of Bacillus Species. J Phys Chem B 2020; 124:7176-7183. [PMID: 32687713 DOI: 10.1021/acs.jpcb.0c03896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The membrane-embedded domain of ATP synthases contains the c-ring, which translocates ions across the membrane, and its resultant rotation is coupled to ATP synthesis in the extramembranous domain. During rotation, the c-ring becomes accessible on both sides of the lipid bilayer to solvent via channels connected to the other membrane-embedded component, the a subunit, and thereby allows the ion to be released into the solvent environment. In recent times, many experimental structures of c-rings from different species have been solved. In some of these, a water molecule with a proposed "structural role" has been identified within the c-ring ion binding site, but in general, the requirement for high resolution to resolve specific water densities complicates their interpretation. In the present study, we use molecular dynamics (MD) simulations and rigorous free energy calculations to characterize the dynamics and energetics of a water molecule within the ion binding site of the c-ring from Bacillus pseudofirmus OF4, in its wild type (WT) and P51A mutant forms, along with the c-ring from thermophilic Bacillus PS3. Our data suggest that a water molecule stably binds to the P51A mutant, as well as helping to identify a bound water molecule in Bacillus PS3 whose presence was previously overlooked due to the limited resolution of the structural data. Sequence analysis further identifies a novel conserved sequence motif that is likely required to harbor a water molecule for stable ion coordination in the binding site of such proteins.
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Affiliation(s)
- Alexander Krah
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Jan K Marzinek
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, Singapore 138671.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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Kang SJ, Todokoro Y, Bak S, Suzuki T, Yoshida M, Fujiwara T, Akutsu H. Direct assignment of 13C solid-state NMR signals of TF oF 1 ATP synthase subunit c-ring in lipid membranes and its implication for the ring structure. JOURNAL OF BIOMOLECULAR NMR 2018; 70:53-65. [PMID: 29197977 DOI: 10.1007/s10858-017-0158-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/28/2017] [Indexed: 06/07/2023]
Abstract
FoF1-ATP synthase catalyzes ATP hydrolysis/synthesis coupled with a transmembrane H+ translocation in membranes. The Fo c-subunit ring plays a major role in this reaction. We have developed an assignment strategy for solid-state 13C NMR (ssNMR) signals of the Fo c-subunit ring of thermophilic Bacillus PS3 (TFo c-ring, 72 residues), carrying one of the basic folds of membrane proteins. In a ssNMR spectrum of uniformly 13C-labeled sample, the signal overlap has been a major bottleneck because most amino acid residues are hydrophobic. To overcome signal overlapping, we developed a method designated as COmplementary Sequential assignment with MInimum Labeling Ensemble (COSMILE). According to this method, we generated three kinds of reverse-labeled samples to suppress signal overlapping. To assign the carbon signals sequentially, two-dimensional Cα(i+1)-C'Cα(i) correlation and dipolar assisted rotational resonance (DARR) experiments were performed under magic-angle sample spinning. On the basis of inter- and intra-residue 13C-13C chemical shift correlations, 97% of Cα, 97% of Cβ and 92% of C' signals were assigned directly from the spectra. Secondary structure analysis predicted a hairpin fold of two helices with a central loop. The effects of saturated and unsaturated phosphatidylcholines on TFo c-ring structure were examined. The DARR spectra at 15 ms mixing time are essentially similar to each other in saturated and unsaturated lipid membranes, suggesting that TFo c-rings have similar structures under the different environments. The spectrum of the sample in saturated lipid membranes showed better resolution and structural stability in the gel state. The C-terminal helix was suggested to locate in the outer layer of the c-ring.
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Affiliation(s)
- Su-Jin Kang
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, 565-0871, Japan
- Department of Biophysics and Chemical Biology, Seoul National University, Kwanak-Gu, Seoul, 151-742, Republic of Korea
| | - Yasuto Todokoro
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, 565-0871, Japan
| | - Suyeon Bak
- Department of Biophysics and Chemical Biology, Seoul National University, Kwanak-Gu, Seoul, 151-742, Republic of Korea
| | - Toshiharu Suzuki
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan
| | - Masasuke Yoshida
- Department of Molecular Bioscience, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, 603-8555, Japan
| | - Toshimichi Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, 565-0871, Japan
| | - Hideo Akutsu
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, 565-0871, Japan.
- Department of Biophysics and Chemical Biology, Seoul National University, Kwanak-Gu, Seoul, 151-742, Republic of Korea.
- Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehirocho, Tsurumi-ku, Yokohama, 230-0045, Japan.
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Abstract
AbstractIncreasing evidence suggests that most proteins occur and function in complexes rather than as isolated entities when embedded in cellular membranes. Nuclear magnetic resonance (NMR) provides increasing possibilities to study structure, dynamics and assembly of such systems. In our review, we discuss recent methodological progress to study membrane–protein complexes (MPCs) by NMR, starting with expression, isotope-labeling and reconstitution protocols. We review approaches to deal with spectral complexity and limited spectral spectroscopic sensitivity that are usually encountered in NMR-based studies of MPCs. We highlight NMR applications in various classes of MPCs, including G-protein-coupled receptors, ion channels and retinal proteins and extend our discussion to protein–protein complexes that span entire cellular compartments or orchestrate processes such as protein transport across or within membranes. These examples demonstrate the growing potential of NMR-based studies of MPCs to provide critical insight into the energetics of protein–ligand and protein–protein interactions that underlie essential biological functions in cellular membranes.
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Brown LS, Ladizhansky V. Membrane proteins in their native habitat as seen by solid-state NMR spectroscopy. Protein Sci 2015; 24:1333-46. [PMID: 25973959 DOI: 10.1002/pro.2700] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 12/21/2022]
Abstract
Membrane proteins play many critical roles in cells, mediating flow of material and information across cell membranes. They have evolved to perform these functions in the environment of a cell membrane, whose physicochemical properties are often different from those of common cell membrane mimetics used for structure determination. As a result, membrane proteins are difficult to study by traditional methods of structural biology, and they are significantly underrepresented in the protein structure databank. Solid-state Nuclear Magnetic Resonance (SSNMR) has long been considered as an attractive alternative because it allows for studies of membrane proteins in both native-like membranes composed of synthetic lipids and in cell membranes. Over the past decade, SSNMR has been rapidly developing into a major structural method, and a growing number of membrane protein structures obtained by this technique highlights its potential. Here we discuss membrane protein sample requirements, review recent progress in SSNMR methodologies, and describe recent advances in characterizing membrane proteins in the environment of a cellular membrane.
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Affiliation(s)
- Leonid S Brown
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
| | - Vladimir Ladizhansky
- Department of Physics and Biophysics Interdepartmental Group, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
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Cardiolipin interaction with subunit c of ATP synthase: solid-state NMR characterization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:260-5. [PMID: 25168468 DOI: 10.1016/j.bbamem.2014.08.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 08/12/2014] [Accepted: 08/16/2014] [Indexed: 01/29/2023]
Abstract
The interaction of lipids with subunit c from F1F0 ATP synthase is studied by biophysical methods. Subunit c from both Escherichia coli and Streptococcus pneumoniae interacts and copurifies with cardiolipin. Solid state NMR data on oligomeric rings of F0 show that the cardiolipin interacts with the c subunit in membrane bilayers. These studies offer strong support for the hypothesis that F0 has specific interactions with cardiolipin.
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Huster D, Madhu PK. Simplifying solid-state NMR spectra for biophysical studies on membrane proteins: selective targeting of sites and interactions. Biophys J 2014; 106:2083-4. [PMID: 24853736 PMCID: PMC4052239 DOI: 10.1016/j.bpj.2014.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/09/2014] [Accepted: 04/10/2014] [Indexed: 12/14/2022] Open
Affiliation(s)
- Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Tata Institute of Fundamental Research, Department of Chemical Sciences, Colaba, Mumbai, India.
| | - Perunthiruthy K Madhu
- Institute of Medical Physics and Biophysics, University of Leipzig, Leipzig, Germany; Tata Institute of Fundamental Research, Department of Chemical Sciences, Colaba, Mumbai, India; Tata Institute of Fundamental Research, Centre for Interdisciplinary Sciences, Narsingi, Hyderabad, India
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