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Wang S, Gopinath T, Larsen EK, Weber DK, Walker C, Uddigiri VR, Mote KR, Sahoo SK, Periasamy M, Veglia G. Structural basis for sarcolipin's regulation of muscle thermogenesis by the sarcoplasmic reticulum Ca 2+-ATPase. SCIENCE ADVANCES 2021; 7:eabi7154. [PMID: 34826239 PMCID: PMC8626070 DOI: 10.1126/sciadv.abi7154] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 10/06/2021] [Indexed: 06/10/2023]
Abstract
The sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA) plays a central role in muscle contractility and nonshivering thermogenesis. SERCA is regulated by sarcolipin (SLN), a single-pass membrane protein that uncouples Ca2+ transport from ATP hydrolysis, promoting futile enzymatic cycles and heat generation. The molecular determinants for regulating heat release by the SERCA/SLN complex are unclear. Using thermocalorimetry, chemical cross-linking, and solid-state NMR spectroscopy in oriented phospholipid bicelles, we show that SERCA’s functional uncoupling and heat release rate are dictated by specific SERCA/SLN intramembrane interactions, with the carboxyl-terminal residues anchoring SLN to the SR membrane in an inhibitory topology. Systematic deletion of the carboxyl terminus does not prevent the SERCA/SLN complex formation but reduces uncoupling in a graded manner. These studies emphasize the critical role of lipids in defining the active topology of SLN and modulating the heat release rate by the SERCA/SLN complex, with implications in fat metabolism and basal metabolic rate.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tata Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Erik K. Larsen
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel K. Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Caitlin Walker
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Venkateswara Reddy Uddigiri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kaustubh R. Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad, Telangana 500046, India
| | - Sanjaya K. Sahoo
- Department of Physiology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Muthu Periasamy
- Department of Physiology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
- Department of Internal Medicine, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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2
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Tong Q, Tan H, Li J, Xie H, Zhao Y, Chen Y, Yang J. Extensively sparse 13C labeling to simplify solid-state NMR 13C spectra of membrane proteins. JOURNAL OF BIOMOLECULAR NMR 2021; 75:245-254. [PMID: 34148188 DOI: 10.1007/s10858-021-00372-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 06/08/2021] [Indexed: 06/12/2023]
Abstract
Solid-state Nuclear Magnetic Resonance (ssNMR) is an emerging technique to investigate the structures and dynamics of membrane proteins in an artificial or native membrane environment. However, the structural studies of proteins by ssNMR are usually prolonged or impeded by signal assignments, especially the assignments of signals for collection of distance restraints, because of serious overlapping of signals in 2D 13C-13C spectra. Sparse labeling of 13C spins is an effective approach to simplify the 13C spectra and facilitate the extractions of distance restraints. Here, we propose a new reverse labeling combination of six types of amino acid residues (Ile, Leu, Phe, Trp, Tyr and Lys), and show a clean reverse labeling effect on a model membrane protein E. coli aquaporin Z (AqpZ). We further combine this reverse labeling combination and alternate 13C-12C labeling, and demonstrate an enhanced dilution effect in 13C-13C spectra. In addition, the influences of reverse labeling on the labeling of the other types of residues are quantitatively analyzed in the two strategies (1, reverse labeling and 2, reverse labeling combining alternate 13C-12C labeling). The signal intensities of some other types of residues in 2D 13C-13C spectra are observed to be 20-50% weaker because of the unwanted reverse labeling. The extensively sparse 13C labeling proposed in this study is expected to be useful in the collection of distance restraints using 2D 13C-13C spectra of membrane proteins.
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Affiliation(s)
- Qiong Tong
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
| | - Huan Tan
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Jianping Li
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Huayong Xie
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Yongxiang Zhao
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Yanke Chen
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China
| | - Jun Yang
- National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, People's Republic of China.
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China.
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Gopinath T, Weber D, Wang S, Larsen E, Veglia G. Solid-State NMR of Membrane Proteins in Lipid Bilayers: To Spin or Not To Spin? Acc Chem Res 2021; 54:1430-1439. [PMID: 33655754 PMCID: PMC11457538 DOI: 10.1021/acs.accounts.0c00670] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Membrane proteins mediate a plethora of cellular functions and represent important targets for drug development. Unlike soluble proteins, membrane proteins require native-like environments to fold correctly and be active. Therefore, modern structural biology techniques have aimed to determine the structure and dynamics of these membrane proteins at physiological temperature and in liquid crystalline lipid bilayers. With the flourishing of new NMR methodologies and improvements in sample preparations, magic angle spinning (MAS) and oriented sample solid-state NMR (OS-ssNMR) spectroscopy of membrane proteins is experiencing a new renaissance. Born as antagonistic approaches, these techniques nowadays offer complementary information on the structural topology and dynamics of membrane proteins reconstituted in lipid membranes. By spinning biosolid samples at the magic angle (θ = 54.7°), MAS NMR experiments remove the intrinsic anisotropy of the NMR interactions, increasing spectral resolution. Internuclear spin interactions (spin exchange) are reintroduced by RF pulses, providing distances and torsion angles to determine secondary, tertiary, and quaternary structures of membrane proteins. OS-ssNMR, on the other hand, directly detects anisotropic NMR parameters such as dipolar couplings (DC) and anisotropic chemical shifts (CS), providing orientational constraints to determine the architecture (i.e., topology) of membrane proteins relative to the lipid membrane. Defining the orientation of membrane proteins and their interactions with lipid membranes is of paramount importance since lipid-protein interactions can shape membrane protein conformations and ultimately define their functional states.In this Account, we report selected studies from our group integrating MAS and OS-ssNMR techniques to give a comprehensive view of the biological processes occurring at cellular membranes. We focus on the main experiments for both techniques, with an emphasis on new implementation to increase both sensitivity and spectral resolution. We also describe how the structural constraints derived from both isotropic and anisotropic NMR parameters are integrated into dynamic structural modeling using replica-averaged orientational-restrained molecular dynamics simulations (RAOR-MD). We showcase small membrane proteins that are involved in Ca2+ transport and regulate cardiac and skeletal muscle contractility: phospholamban (PLN, 6 kDa), sarcolipin (SLN, 4 kDa), and DWORF (4 kDa). We summarize our results for the structures of these polypeptides free and in complex with the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA, 110 kDa). Additionally, we illustrate the progress toward the determination of the structural topology of a six transmembrane protein associated with succinate and acetate transport (SatP, hexamer 120 kDa). From these examples, the integrated MAS and OS-ssNMR approach, in combination with modern computational methods, emerges as a way to overcome the challenges posed by studying large membrane protein systems.
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4
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Weber DK, Veglia G. A theoretical assessment of structure determination of multi-span membrane proteins by oriented sample solid-state NMR spectroscopy. Aust J Chem 2020; 73:246-251. [PMID: 33162560 DOI: 10.1071/ch19307] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Oriented sample solid state NMR (OS-ssNMR) spectroscopy allows direct determination of the structure and topology of membrane proteins reconstituted into aligned lipid bilayers. While OS-ssNMR theoretically has no upper size limit, its application to multi-span membrane proteins has not been established since most studies have been restricted to single or dual span proteins and peptides. Here, we present a critical assessment of the application of this method to multi-span membrane proteins. We used molecular dynamics simulations to back-calculate [15N-1H] separated local field (SLF) spectra from a G protein-coupled receptor (GPCR) and show that fully resolved spectra can be obtained theoretically for a multi-span membrane protein with currently achievable resonance linewidths.
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Affiliation(s)
- Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.,Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
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Li M, Heller WT, Liu CH, Gao CY, Cai Y, Hou Y, Nieh MP. Effects of fluidity and charge density on the morphology of a bicellar mixture - A SANS study. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183315. [PMID: 32304755 DOI: 10.1016/j.bbamem.2020.183315] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/11/2020] [Accepted: 04/13/2020] [Indexed: 01/28/2023]
Abstract
The spontaneously formed structures of physiologically relevant lipid model membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1,2-hexanoyl-sn-glycero-3-phosphocholine have been evaluated in depth using small angle neutron scattering. Although a common molar ratio of long- to short- chain phospholipids (~4) as reported in many bicellar mixtures was used, discoidal bicelles were not found as the major phase throughout the range of lipid concentration and temperature studied, indicating that the required condition for the formation of bicelle is the immiscibility between the long- and short- chain lipids, which were in the gel and Lα phases, respectively, in previous reports. In this study, all lipids are in the Lα phase. The characterization outcome suggests that the spontaneous structures tie strongly with the physical parameters of the system such as melting transition temperature of the long-chain lipid, total lipid concentration and charge density of the system. Multilamellar vesicles, unilamellar vesicles, ribbons and perforated lamellae can be obtained based on the analysis of the small angle neutron scattering results, leading to the construction of structural diagrams. This report provides the important map to choose suitable lipid systems for the structural study of membrane-associated proteins, design of theranostic nanocarriers or other related research fields.
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Affiliation(s)
- Ming Li
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chung-Hao Liu
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA
| | - Carrie Y Gao
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yutian Cai
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Yiming Hou
- Department of Polymer Material Science and Engineering, College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410000, China
| | - Mu-Ping Nieh
- Polymer Program, Institute of Materials Science, University of Connecticut, Storrs, 06269, USA; Department of Chemical & Biomolecular Engineering, University of Connecticut, Storrs 06269, USA; Department of Biomedical Engineering, University of Connecticut, Storrs 06269, USA.
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6
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Gadolinium Complexes as Contrast Agent for Cellular NMR Spectroscopy. Int J Mol Sci 2020; 21:ijms21114042. [PMID: 32516957 PMCID: PMC7312942 DOI: 10.3390/ijms21114042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 05/27/2020] [Accepted: 06/03/2020] [Indexed: 02/07/2023] Open
Abstract
Aqua Gd3+ and Gd-DOTA (gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacete) complexes were studied as a contrast agent in cellular NMR (nuclear magnetic resonance) spectroscopy for distinguishing between intracellular and extracellular spaces. The contrast agents for this purpose should provide strong paramagnetic relaxation enhancement and localize in the extracellular space without disturbing biological functions. Cell membrane permeability to Gd complexes was evaluated from the concentrations of gadolinium complexes in the inside and outside of E. coli cells measured by the 1H-NMR relaxation. The site-specific binding of the complexes to E. coli cells was also analyzed by high-resolution solid-state 13C-NMR. The aqua Gd3+ complex did not enhance T1 relaxation in proportion to the amount of added Gd3+. This Gd3+ concentration dependence and the 13C-NMR indicated that its strong cytotoxicity should be due to the binding of the paramagnetic ions to cellular components especially at the lipid membranes. In contrast, Gd-DOTA stayed in the solution states and enhanced relaxation in proportion to the added amount. This agent exhibited strong T1 contrast between the intra- and extracellular spaces by a factor of ten at high concentrations under which the cells were viable over a long experimental time of days. These properties make Gd-DOTA suitable for selectively contrasting the living cellular space in NMR spectroscopy primarily owing to its weak interaction with cellular components.
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7
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Tang M, Lam D. Paramagnetic solid-state NMR of proteins. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 103:9-16. [PMID: 31585788 DOI: 10.1016/j.ssnmr.2019.101621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
The paramagnetic properties of metal ions and stable radicals can affect NMR spectra, which can lead to changes in peak intensities, relaxation times and chemical shifts. The changes from paramagnetic effects provide intriguing opportunities for solid-state NMR studies of proteins. In this review, we summarized the trends and progress of paramagnetic solid-state NMR of proteins in the past decade, and showed that paramagnetic effects have great potential applications for sensitivity enhancement, structure determination and topological analysis for microcrystalline proteins, protein complexes, protein aggregates and membrane proteins.
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Affiliation(s)
- Ming Tang
- Department of Chemistry, College of Staten Island - Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA.
| | - Dennis Lam
- Department of Chemistry, College of Staten Island - Ph.D. Programs in Chemistry and Biochemistry, The Graduate Center of the City University of New York, New York, NY, 10016, USA
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8
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Wang S, Gopinath T, Veglia G. Improving the quality of oriented membrane protein spectra using heat-compensated separated local field experiments. JOURNAL OF BIOMOLECULAR NMR 2019; 73:617-624. [PMID: 31463642 PMCID: PMC6861693 DOI: 10.1007/s10858-019-00273-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/21/2019] [Indexed: 05/03/2023]
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is a powerful technique to determine the topology of membrane proteins in oriented lipid bilayers. Separated local field (SLF) experiments are central to this technique as they provide first-order orientational restraints, i.e., dipolar couplings and anisotropic chemical shifts. Despite the use of low-E (or E-free) probes, the heat generated during the execution of 2D and 3D SLF pulse sequences causes sizeable line-shape distortions. Here, we propose a new heat-compensated SE-SAMPI4 (hcSE-SAMPI4) pulse sequence that holds the temperature constant for the duration of the experiment. This modification of the SE-SAMPI4 results in sharper and more intense resonances without line-shape distortions. The spectral improvements are even more apparent when paramagnetic relaxation agents are used to speed up data collection. We tested the hcSE-SAMPI4 pulse sequence on a single-span membrane protein, sarcolipin (SLN), reconstituted in magnetically aligned lipid bicelles. In addition to eliminating peak distortions, the hcSE-SAMPI4 experiment increased the average signal-to-noise ratio by 20% with respect to the original SE-SAMPI4.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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9
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Kocman V, Di Mauro GM, Veglia G, Ramamoorthy A. Use of paramagnetic systems to speed-up NMR data acquisition and for structural and dynamic studies. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2019; 102:36-46. [PMID: 31325686 PMCID: PMC6698407 DOI: 10.1016/j.ssnmr.2019.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 05/05/2023]
Abstract
NMR spectroscopy is a powerful experimental technique to study biological systems at the atomic resolution. However, its intrinsic low sensitivity results in long acquisition times that in extreme cases lasts for days (or even weeks) often exceeding the lifetime of the sample under investigation. Different paramagnetic agents have been used in an effort to decrease the spin-lattice (T1) relaxation times of the studied nuclei, which are the main cause for long acquisition times necessary for signal averaging to enhance the signal-to-noise ratio of NMR spectra. Consequently, most of the experimental time is "wasted" in waiting for the magnetization to recover between successive scans. In this review, we discuss how to set up an optimal paramagnetic relaxation enhancement (PRE) system to effectively reduce the T1 relaxation times avoiding significant broadening of NMR signals. Additionally, we describe how PRE-agents can be used to provide structural and dynamic information and can even be used to follow the intermediates of chemical reactions and to speed-up data acquisition. We also describe the unique challenges and benefits associated with the application of PRE to solid-state NMR spectroscopy, explaining how the use of PREs is more complex for membrane mimetic systems as PREs can also be exploited to change the alignment of oriented membrane systems. Functionalization of membrane mimetics, such as bicelles, can provide a controlled region of paramagnetic effect that has the potential, together with the desired alignment, to provide crucial biologically relevant structural information. And finally, we discuss how paramagnetic metals can be utilized to further increase the dynamic nuclear polarization (DNP) effects and how to preserve the enhancements when dissolution DNP is implemented.
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Affiliation(s)
- Vojč Kocman
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA; Biophysics, Biomedical Engineering, Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, USA.
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10
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Weber DK, Bader T, Larsen EK, Wang S, Gopinath T, Distefano M, Veglia G. Cysteine-ethylation of tissue-extracted membrane proteins as a tool to detect conformational states by solid-state NMR spectroscopy. Methods Enzymol 2019; 621:281-304. [PMID: 31128784 DOI: 10.1016/bs.mie.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Solid-state NMR (ssNMR) is an ideal tool to study structure and dynamics of membrane proteins in their native lipid environment. In principle, ssNMR has no size limitations. However, this feature is rarely exploited as large membrane proteins display severe resonance overlap. In addition, dismal yields from recombinant bacterial expression systems limit severely spectroscopic characterization of membrane proteins. For very large mammalian membrane proteins, extraction from the original organism remains the most viable approach. In this case, NMR-observable nuclei must be introduced post-translationally, but the approaches developed so far are rather scarce. Here, we detail the synthesis and engineering of a reactive 13C-ethylmethanethiosulfonate (13C-EMTS) reagent for the post-translational alkylation of cysteine sidechains of a 110kDa sarcoplasmic reticulum Ca2+-ATPase (SERCA) extracted from rabbit skeletal muscle tissue. When reconstituted into liposomes, it is possible to resolve the resonances of the engineered ethyl groups by magic-angle spinning (MAS) 2D [13C,13C]-DARR experiments. Notably, the ethyl-group modification does not perturb the function of SERCA, yielding well-resolved 13C-13C fingerprints that are used to image its structural states in the catalytic cycle and filtering out overwhelming naturally-abundant 13C nuclei signals arising from the enzyme and lipids. We anticipate that this approach will be used together with 19F NMR to monitor conformational transitions of enzymes and proteins that are difficult to express recombinantly.
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Affiliation(s)
- Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Taysir Bader
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Erik K Larsen
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Tata Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States
| | - Mark Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, MN, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, United States; Department of Chemistry, University of Minnesota, Minneapolis, MN, United States.
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11
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Salnikov ES, Aisenbrey C, Anantharamaiah G, Bechinger B. Solid-state NMR structural investigations of peptide-based nanodiscs and of transmembrane helices in bicellar arrangements. Chem Phys Lipids 2019; 219:58-71. [DOI: 10.1016/j.chemphyslip.2019.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/29/2019] [Accepted: 01/29/2019] [Indexed: 02/08/2023]
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12
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Ravula T, Hardin NZ, Di Mauro GM, Ramamoorthy A. Styrene maleic acid derivates to enhance the applications of bio-inspired polymer based lipid-nanodiscs. Eur Polym J 2018; 108:597-602. [PMID: 31105326 PMCID: PMC6516473 DOI: 10.1016/j.eurpolymj.2018.09.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Membrane mimetics are essential to study the structure, dynamics and function of membrane-associated proteins by biophysical and biochemical approaches. Among various membrane mimetics that have been developed and demonstrated for studies on membrane proteins, lipid nanodiscs are the latest developments in the field and are increasingly used for various applications. While lipid-nanodiscs can be formed using an amphipathic membrane scaffold protein (MSP), peptide, or synthetic polymer, the synthetic polymer based nanodiscs exhibit unique advantages because of the ability to functionalize them for various applications. In addition to the use of synthetic polymers to extract membrane proteins directly from the cell membranes, recent advances in the development of polymers used for nanodiscs formation are attracting new attention to the field of nanodiscs technology. Here we review the developments of novel polymer modifications that overcome the current limitations and enhance the applications of polymer based nanodiscs to a wider variety of biophysical techniques used to study membrane proteins. A summary of the functionalization of poly(Styrene-co-Maleic Acid), SMA, polymers developed by our research and their advantages are also covered in this review article.
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Affiliation(s)
- Thirupathi Ravula
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Nathaniel. Z Hardin
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Giacomo M. Di Mauro
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics Program and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
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13
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NMR Methods of Characterizing Biomolecular Structural Dynamics and Conformational Ensembles. Methods 2018; 148:1-3. [DOI: 10.1016/j.ymeth.2018.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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14
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New Methods in Biomolecular Nuclear Magnetic Resonance Spectroscopy. Methods 2018; 138-139:1-2. [DOI: 10.1016/j.ymeth.2018.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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