1
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Taware PP, Raran-Kurussi S, Mote KR. CURD: a Single-Shot Strategy to Obtain Assignments and Distance Restraints for Proteins Using Solid-State MAS NMR Spectroscopy. J Phys Chem B 2022; 126:3269-3275. [PMID: 35473315 DOI: 10.1021/acs.jpcb.2c00775] [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
We present a strategy dubbed CURD (correlations using recycle delays) to acquire chemical-shift assignments and distance restraints for proteins in a single experimental block under slow-moderate magic-angle spinning conditions. This is done by concatenating the 3D-CCC and 3D-NNC experiments, both of which individually require long experimental times for sufficient resolution and sensitivity to be realized. Unlike previous approaches, the CURD strategy does not increase the amount of radio-frequency deposition on the sample and does not require lengthy procedures to optimize any of the pulse sequence elements. Instead, time savings is obtained by using the hitherto unused recycle delay of one of the experiments (2D-CC/3D-CCC) to establish inter-residue correlations for the second experiment (2D-NN/3D-NNC). Experiments are demonstrated on a model protein at the MAS frequency of 12.5 kHz and are shown to result in time savings of the order of days for most of the routine cases.
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Affiliation(s)
- Pravin P Taware
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana 500046, India
| | - Sreejith Raran-Kurussi
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana 500046, India
| | - Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally Village, Serilingampally Mandal, Ranga Reddy District, Hyderabad, Telangana 500046, India
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2
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Abstract
In the last two decades, solid-state nuclear magnetic resonance (ssNMR) spectroscopy has transformed from a spectroscopic technique investigating small molecules and industrial polymers to a potent tool decrypting structure and underlying dynamics of complex biological systems, such as membrane proteins, fibrils, and assemblies, in near-physiological environments and temperatures. This transformation can be ascribed to improvements in hardware design, sample preparation, pulsed methods, isotope labeling strategies, resolution, and sensitivity. The fundamental engagement between nuclear spins and radio-frequency pulses in the presence of a strong static magnetic field is identical between solution and ssNMR, but the experimental procedures vastly differ because of the absence of molecular tumbling in solids. This review discusses routinely employed state-of-the-art static and MAS pulsed NMR methods relevant for biological samples with rotational correlation times exceeding 100's of nanoseconds. Recent developments in signal filtering approaches, proton methodologies, and multiple acquisition techniques to boost sensitivity and speed up data acquisition at fast MAS are also discussed. Several examples of protein structures (globular, membrane, fibrils, and assemblies) solved with ssNMR spectroscopy have been considered. We also discuss integrated approaches to structurally characterize challenging biological systems and some newly emanating subdisciplines in ssNMR spectroscopy.
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Affiliation(s)
- Sahil Ahlawat
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Nils-Alexander Lakomek
- University of Düsseldorf, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Vipin Agarwal
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
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3
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Lusky OS, Meir M, Goldbourt A. Characterizing hydrogen bonds in intact RNA from MS2 bacteriophage using magic angle spinning NMR. BIOPHYSICAL REPORTS 2021; 1:100027. [PMID: 36425459 PMCID: PMC9680805 DOI: 10.1016/j.bpr.2021.100027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/23/2021] [Indexed: 05/14/2023]
Abstract
RNA is a polymer with pivotal functions in many biological processes. RNA structure determination is thus a vital step toward understanding its function. The secondary structure of RNA is stabilized by hydrogen bonds formed between nucleotide basepairs, and it defines the positions and shapes of functional stem-loops, internal loops, bulges, and other functional and structural elements. In this work, we present a methodology for studying large intact RNA biomolecules using homonuclear 15N solid-state NMR spectroscopy. We show that proton-driven spin-diffusion experiments with long mixing times, up to 16 s, improved by the incorporation of multiple rotor-synchronous 1H inversion pulses (termed radio-frequency dipolar recoupling pulses), reveal key hydrogen-bond contacts. In the full-length RNA isolated from MS2 phage, we observed strong and dominant contributions of guanine-cytosine Watson-Crick basepairs, and beyond these common interactions, we observe a significant contribution of the guanine-uracil wobble basepairs. Moreover, we can differentiate basepaired and non-basepaired nitrogen atoms. Using the improved technique facilitates characterization of hydrogen-bond types in intact large-scale RNA using solid-state NMR. It can be highly useful to guide secondary structure prediction techniques and possibly structure determination methods.
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Affiliation(s)
| | - Moran Meir
- School of Molecular Cell Biology and Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Amir Goldbourt
- School of Chemistry, Faculty of Exact Sciences
- Corresponding author
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4
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Weber DK, Reddy UV, Wang S, Larsen EK, Gopinath T, Gustavsson MB, Cornea RL, Thomas DD, De Simone A, Veglia G. Structural basis for allosteric control of the SERCA-Phospholamban membrane complex by Ca 2+ and phosphorylation. eLife 2021; 10:66226. [PMID: 33978571 PMCID: PMC8184213 DOI: 10.7554/elife.66226] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 05/10/2021] [Indexed: 01/26/2023] Open
Abstract
Phospholamban (PLN) is a mini-membrane protein that directly controls the cardiac Ca2+-transport response to β-adrenergic stimulation, thus modulating cardiac output during the fight-or-flight response. In the sarcoplasmic reticulum membrane, PLN binds to the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA), keeping this enzyme's function within a narrow physiological window. PLN phosphorylation by cAMP-dependent protein kinase A or increase in Ca2+ concentration reverses the inhibitory effects through an unknown mechanism. Using oriented-sample solid-state NMR spectroscopy and replica-averaged NMR-restrained structural refinement, we reveal that phosphorylation of PLN's cytoplasmic regulatory domain signals the disruption of several inhibitory contacts at the transmembrane binding interface of the SERCA-PLN complex that are propagated to the enzyme's active site, augmenting Ca2+ transport. Our findings address long-standing questions about SERCA regulation, epitomizing a signal transduction mechanism operated by posttranslationally modified bitopic membrane proteins.
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Affiliation(s)
- Daniel K Weber
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - U Venkateswara Reddy
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Songlin Wang
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Erik K Larsen
- Department of Chemistry, University of Minnesota, Minneapolis, United States
| | - Tata Gopinath
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Martin B Gustavsson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States
| | - Alfonso De Simone
- Department of Life Sciences, Imperial College London, South Kensington, London, United Kingdom.,Department of Pharmacy, University of Naples 'Federico II', Naples, Italy
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, United States.,Department of Chemistry, University of Minnesota, Minneapolis, United States
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5
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Kupče Ē, Mote KR, Madhu PK. Experiments with direct detection of multiple FIDs. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 304:16-34. [PMID: 31077929 DOI: 10.1016/j.jmr.2019.04.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/26/2019] [Accepted: 04/29/2019] [Indexed: 05/04/2023]
Abstract
Pulse schemes with direct observation of multiple free induction decays (FIDs) offer a dramatic increase in the spectral information content of NMR experiments and often yield substantial improvement in measurement sensitivity per unit time. Availability of multiple receivers on the state-of-the-art commercial spectrometers allows spectra from different nuclear species to be recorded in parallel routinely. Experiments with multi-FID detection have been designed with both, homonuclear and multinuclear acquisition. We provide a brief overview of such techniques designed for applications in liquid- and solid- state NMR as well as in hyperpolarized samples. Here we show how these techniques have led to design of experiments that allow structure elucidation of small molecules and resonance assignment in proteins from a single measurement. Probes with multiple RF micro-coils routed to multiple NMR receivers provide an alternative way of increasing the throughput of modern NMR systems. Solid-state NMR experiments have also benefited immensely from both parallel and simultaneous FID acquisition in a variety of multi-dimensional pulse schemes. We believe that multi-FID detection will become an essential component of the future NMR methodologies effectively increasing the information content of NMR experiments and reducing the cost of NMR analysis.
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Affiliation(s)
- Ēriks Kupče
- Bruker UK Ltd., Banner Lane, Coventry CV4 9GH, United Kingdom.
| | - Kaustubh R Mote
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally Village, Ranga Reddy District, Hyderabad 500107, India
| | - Perunthiruthy K Madhu
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally Village, Ranga Reddy District, Hyderabad 500107, India
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6
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Leninger M, Traaseth NJ. NMR Spectroscopy Approach to Study the Structure, Orientation, and Mechanism of the Multidrug Exporter EmrE. Methods Mol Biol 2018; 1700:83-96. [PMID: 29177827 PMCID: PMC5926179 DOI: 10.1007/978-1-4939-7454-2_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Multidrug exporters are a class of membrane proteins that remove antibiotics from the cytoplasm of bacteria and in the process confer multidrug resistance to the organism. This chapter outlines the sample preparation and optimization of oriented solid-state NMR experiments applied to the study of structure and dynamics for the model transporter EmrE from the small multidrug resistance (SMR) family.
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Affiliation(s)
- Maureen Leninger
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA
| | - Nathaniel J Traaseth
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY, 10003, USA.
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7
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Wang S, Gopinath T, Veglia G. Application of paramagnetic relaxation enhancements to accelerate the acquisition of 2D and 3D solid-state NMR spectra of oriented membrane proteins. Methods 2017; 138-139:54-61. [PMID: 29274874 DOI: 10.1016/j.ymeth.2017.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/14/2017] [Accepted: 12/19/2017] [Indexed: 12/21/2022] Open
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is uniquely suited to determine membrane protein topology at the atomic resolution in liquid crystalline bilayers under physiological temperature. However, the inherent low sensitivity of this technique has hindered the throughput of multidimensional experiments necessary for resonance assignments and structure determination. In this work, we show that doping membrane protein bicelle preparations with paramagnetic ion chelated lipids and exploiting paramagnetic relaxation effects it is possible to accelerate the acquisition of both 2D and 3D multidimensional experiments with significant saving in time. We demonstrate the efficacy of this method for a small membrane protein, sarcolipin, reconstituted in DMPC/POPC/DHPC oriented bicelles. In particular, using Cu2+-DMPE-DTPA as a dopant, we observed a decrease of 1H T1 of sarcolipin by 2/3, allowing us to reduce the recycle delay up to 3 times. We anticipate that these new developments will enable the routine acquisition of multidimensional OS-ssNMR experiments.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States; Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, United States.
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8
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Donovan KJ, Silvers R, Linse S, Griffin RG. 3D MAS NMR Experiment Utilizing Through-Space 15N- 15N Correlations. J Am Chem Soc 2017; 139:6518-6521. [PMID: 28447786 DOI: 10.1021/jacs.7b01159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We demonstrate a novel 3D NNC magic angle spinning NMR experiment that generates 15N-15N internuclear contacts in protein systems using an optimized 15N-15N proton assisted recoupling (PAR) mixing period and a 13C dimension for improved resolution. The optimized PAR condition permits the acquisition of high signal-to-noise 3D data that enables backbone chemical shift assignments using a strategy that is complementary to current schemes. The spectra can also provide distance constraints. The utility of the experiment is demonstrated on an M0Aβ1-42 fibril sample that yields high-quality data that is readily assigned and interpreted. The 3D NNC experiment therefore provides a powerful platform for solid-state protein studies and is broadly applicable to a variety of systems and experimental conditions.
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Affiliation(s)
- Kevin J Donovan
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Robert Silvers
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University , Lund 221 00, Sweden
| | - Robert G Griffin
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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9
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Koroloff SN, Nevzorov AA. Selective excitation for spectral editing and assignment in separated local field experiments of oriented membrane proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:7-12. [PMID: 27835748 DOI: 10.1016/j.jmr.2016.10.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 10/18/2016] [Accepted: 10/23/2016] [Indexed: 06/06/2023]
Abstract
Spectroscopic assignment of NMR spectra for oriented uniformly labeled membrane proteins embedded in their native-like bilayer environment is essential for their structure determination. However, sequence-specific assignment in oriented-sample (OS) NMR is often complicated by insufficient resolution and spectral crowding. Therefore, the assignment process is usually done by a laborious and expensive "shotgun" method involving multiple selective labeling of amino acid residues. Presented here is a strategy to overcome poor spectral resolution in crowded regions of 2D spectra by selecting resolved "seed" residues via soft Gaussian pulses inserted into spin-exchange separated local-field experiments. The Gaussian pulse places the selected polarization along the z-axis while dephasing the other signals before the evolution of the 1H-15N dipolar couplings. The transfer of magnetization is accomplished via mismatched Hartmann-Hahn conditions to the nearest-neighbor peaks via the proton bath. By optimizing the length and amplitude of the Gaussian pulse, one can also achieve a phase inversion of the closest peaks, thus providing an additional phase contrast. From the superposition of the selective spin-exchanged SAMPI4 onto the fully excited SAMPI4 spectrum, the 15N sites that are directly adjacent to the selectively excited residues can be easily identified, thereby providing a straightforward method for initiating the assignment process in oriented membrane proteins.
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Affiliation(s)
- Sophie N Koroloff
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, USA
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, USA.
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10
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Gopinath T, Mote KR, Veglia G. Simultaneous acquisition of 2D and 3D solid-state NMR experiments for sequential assignment of oriented membrane protein samples. JOURNAL OF BIOMOLECULAR NMR 2015; 62:53-61. [PMID: 25749871 PMCID: PMC4981477 DOI: 10.1007/s10858-015-9916-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 03/03/2015] [Indexed: 05/20/2023]
Abstract
We present a new method called DAISY (Dual Acquisition orIented ssNMR spectroScopY) for the simultaneous acquisition of 2D and 3D oriented solid-state NMR experiments for membrane proteins reconstituted in mechanically or magnetically aligned lipid bilayers. DAISY utilizes dual acquisition of sine and cosine dipolar or chemical shift coherences and long living (15)N longitudinal polarization to obtain two multi-dimensional spectra, simultaneously. In these new experiments, the first acquisition gives the polarization inversion spin exchange at the magic angle (PISEMA) or heteronuclear correlation (HETCOR) spectra, the second acquisition gives PISEMA-mixing or HETCOR-mixing spectra, where the mixing element enables inter-residue correlations through (15)N-(15)N homonuclear polarization transfer. The analysis of the two 2D spectra (first and second acquisitions) enables one to distinguish (15)N-(15)N inter-residue correlations for sequential assignment of membrane proteins. DAISY can be implemented in 3D experiments that include the polarization inversion spin exchange at magic angle via I spin coherence (PISEMAI) sequence, as we show for the simultaneous acquisition of 3D PISEMAI-HETCOR and 3D PISEMAI-HETCOR-mixing experiments.
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Affiliation(s)
| | | | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455
- Department of Chemistry and University of Minnesota, Minneapolis, MN 55455
- Corresponding Author. Gianluigi Veglia, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN 55455, Phone: (612) 625-0758, Fax: (612) 625-2163,
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11
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Cho MK, Gayen A, Banigan J, Leninger M, Traaseth NJ. Intrinsic conformational plasticity of native EmrE provides a pathway for multidrug resistance. J Am Chem Soc 2014; 136:8072-80. [PMID: 24856154 PMCID: PMC4063181 DOI: 10.1021/ja503145x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Indexed: 12/24/2022]
Abstract
EmrE is a multidrug resistance efflux pump with specificity to a wide range of antibiotics and antiseptics. To obtain atomic-scale insight into the attributes of the native state that encodes the broad specificity, we used a hybrid of solution and solid-state NMR methods in lipid bilayers and bicelles. Our results indicate that the native EmrE dimer oscillates between inward and outward facing structural conformations at an exchange rate (k(ex)) of ~300 s(-1) at 37 °C (millisecond motions), which is ~50-fold faster relative to the tetraphenylphosphonium (TPP(+)) substrate-bound form of the protein. These observables provide quantitative evidence that the rate-limiting step in the TPP(+) transport cycle is not the outward-inward conformational change in the absence of drug. In addition, using differential scanning calorimetry, we found that the width of the gel-to-liquid crystalline phase transition was 2 °C broader in the absence of the TPP(+) substrate versus its presence, which suggested that changes in transporter dynamics can impact the phase properties of the membrane. Interestingly, experiments with cross-linked EmrE showed that the millisecond inward-open to outward-open dynamics was not the culprit of the broadening. Instead, the calorimetry and NMR data supported the conclusion that faster time scale structural dynamics (nanosecond-microsecond) were the source and therefore impart the conformationally plastic character of native EmrE capable of binding structurally diverse substrates. These findings provide a clear example how differences in membrane protein transporter structural dynamics between drug-free and bound states can have a direct impact on the physical properties of the lipid bilayer in an allosteric fashion.
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Affiliation(s)
| | | | - James
R. Banigan
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Maureen Leninger
- Department of Chemistry, New York University, New York, New York 10003, United States
| | - Nathaniel J. Traaseth
- Department of Chemistry, New York University, New York, New York 10003, United States
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12
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Abstract
In the stationary, aligned samples used in oriented sample (OS) solid-state NMR, (1)H-(1)H homonuclear dipolar couplings are not attenuated as they are in magic angle spinning solid-state NMR; consequently, they are available for participation in dipolar coupling-based spin-exchange processes. Here we describe analytically the pathways of (15)N-(15)N spin-exchange mediated by (1)H-(1)H homonuclear dipolar couplings. The mixed-order proton-relay mechanism can be differentiated from the third spin assisted recoupling mechanism by setting the (1)H to an off-resonance frequency so that it is at the "magic angle" during the spin-exchange interval in the experiment, since the "magic angle" irradiation nearly quenches the former but only slightly attenuates the latter. Experimental spectra from a single crystal of N-acetyl leucine confirm that this proton-relay mechanism plays the dominant role in (15)N-(15)N dilute-spin-exchange in OS solid-state NMR in crystalline samples. Remarkably, the "forbidden" spin-exchange condition under "magic angle" irradiation results in (15)N-(15)N cross-peaks intensities that are comparable to those observed with on-resonance irradiation in applications to proteins. The mechanism of the proton relay in dilute-spin-exchange is crucial for the design of polarization transfer experiments.
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Affiliation(s)
- George J Lu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0307, USA
| | - Stanley J Opella
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0307, USA
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13
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Lu GJ, Opella SJ. Resonance assignments of a membrane protein in phospholipid bilayers by combining multiple strategies of oriented sample solid-state NMR. JOURNAL OF BIOMOLECULAR NMR 2014; 58:69-81. [PMID: 24356892 PMCID: PMC3928288 DOI: 10.1007/s10858-013-9806-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 12/12/2013] [Indexed: 06/01/2023]
Abstract
Oriented sample solid-state NMR spectroscopy can be used to determine the three-dimensional structures of membrane proteins in magnetically or mechanically aligned lipid bilayers. The bottleneck for applying this technique to larger and more challenging proteins is making resonance assignments, which is conventionally accomplished through the preparation of multiple selectively isotopically labeled samples and performing an analysis of residues in regular secondary structure based on Polarity Index Slant Angle (PISA) Wheels and Dipolar Waves. Here we report the complete resonance assignment of the full-length mercury transporter, MerF, an 81-residue protein, which is challenging because of overlapping PISA Wheel patterns from its two trans-membrane helices, by using a combination of solid-state NMR techniques that improve the spectral resolution and provide correlations between residues and resonances. These techniques include experiments that take advantage of the improved resolution of the MSHOT4-Pi4/Pi pulse sequence; the transfer of resonance assignments through frequency alignment of heteronuclear dipolar couplings, or through dipolar coupling correlated isotropic chemical shift analysis; (15)N/(15)N dilute spin exchange experiments; and the use of the proton-evolved local field experiment with isotropic shift analysis to assign the irregular terminal and loop regions of the protein, which is the major "blind spot" of the PISA Wheel/Dipolar Wave method.
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14
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Gopinath T, Mote KR, Veglia G. Sensitivity and resolution enhancement of oriented solid-state NMR: application to membrane proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 75:50-68. [PMID: 24160761 PMCID: PMC3850070 DOI: 10.1016/j.pnmrs.2013.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/16/2013] [Indexed: 05/19/2023]
Abstract
Oriented solid-state NMR (O-ssNMR) spectroscopy is a major technique for the high-resolution analysis of the structure and topology of transmembrane proteins in native-like environments. Unlike magic angle spinning (MAS) techniques, O-ssNMR spectroscopy requires membrane protein preparations that are uniformly oriented (mechanically or magnetically) so that anisotropic NMR parameters, such as dipolar and chemical shift interactions, can be measured to determine structure and orientation of membrane proteins in lipid bilayers. Traditional sample preparations involving mechanically aligned lipids often result in short relaxation times which broaden the (15)N resonances and encumber the manipulation of nuclear spin coherences. The introduction of lipid bicelles as membrane mimicking systems has changed this scenario, and the more favorable relaxation properties of membrane protein (15)N and (13)C resonances make it possible to develop new, more elaborate pulse sequences for higher spectral resolution and sensitivity. Here, we describe our recent progress in the optimization of O-ssNMR pulse sequences. We explain the theory behind these experiments, demonstrate their application to small and medium size proteins, and describe the technical details for setting up these new experiments on the new generation of NMR spectrometers.
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Affiliation(s)
- T. Gopinath
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Kaustubh R. Mote
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, United States
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15
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Das BB, Lin EC, Opella SJ. Experiments optimized for magic angle spinning and oriented sample solid-state NMR of proteins. J Phys Chem B 2013; 117:12422-31. [PMID: 24044695 DOI: 10.1021/jp407154h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Structure determination by solid-state NMR of proteins is rapidly advancing as a result of recent developments of samples, experimental methods, and calculations. There are a number of different solid-state NMR approaches that utilize stationary samples, aligned samples, or magic angle spinning of unoriented "powder" samples, and depending on the sample and the experimental method they can emphasize the measurement of distances or angles, ideally both, as sources of structural constraints. Multidimensional correlation spectroscopy of low-gamma nuclei such as (15)N and (13)C is an important step for making resonance assignments and measurements of angular restraints in membrane proteins. However, the efficiency of coherence transfer predominantly depends upon the strength of the dipole-dipole interaction, and this can vary from site to site and between sample alignments, for example, during the mixing of (13)C and (15)N magnetization in stationary aligned and in magic angle spinning samples. Here, we demonstrate that the efficiency of polarization transfer can be improved by using adiabatic demagnetization and remagnetization techniques on stationary aligned samples, and proton assisted insensitive nuclei cross-polarization in magic angle sample spinning samples. The adiabatic cross-polarization technique provides an alternative mechanism for spin-diffusion experiments correlating (15)N/(15)N and (15)N/(13)C chemical shifts over large distances. Improved efficiency in cross-polarization with 40-100% sensitivity enhancements is observed in proteins and single crystals, respectively. We describe solid-state NMR experimental techniques that are optimal for membrane proteins in liquid crystalline phospholipid bilayers under physiological conditions. The techniques are illustrated with data from single crystals both of peptides and of membrane proteins in phospholipid bilayers.
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Affiliation(s)
- Bibhuti B Das
- University of California, San Diego , 9500 Gilman Drive, 0307 La Jolla, California 92093-0307, United States
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Gayen A, Banigan JR, Traaseth NJ. Ligand-induced conformational changes of the multidrug resistance transporter EmrE probed by oriented solid-state NMR spectroscopy. Angew Chem Int Ed Engl 2013; 52:10321-4. [PMID: 23939862 DOI: 10.1002/anie.201303091] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/12/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Anindita Gayen
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 (USA) http://www.nyu.edu/fas/dept/chemistry/traasethgroup/
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Gayen A, Banigan JR, Traaseth NJ. Ligand-Induced Conformational Changes of the Multidrug Resistance Transporter EmrE Probed by Oriented Solid-State NMR Spectroscopy. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201303091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Tang W, Knox RW, Nevzorov AA. A spectroscopic assignment technique for membrane proteins reconstituted in magnetically aligned bicelles. JOURNAL OF BIOMOLECULAR NMR 2012; 54:307-316. [PMID: 22976525 DOI: 10.1007/s10858-012-9673-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 09/06/2012] [Indexed: 06/01/2023]
Abstract
Oriented-sample NMR (OS-NMR) has emerged as a powerful tool for the structure determination of membrane proteins in their physiological environments. However, the traditional spectroscopic assignment method in OS NMR that uses the "shotgun" approach, though effective, is quite labor- and time-consuming as it is based on the preparation of multiple selectively labeled samples. Here we demonstrate that, by using a combination of the spin exchange under mismatched Hartmann-Hahn conditions and a recent sensitivity-enhancement REP-CP sequence, spectroscopic assignment of solid-state NMR spectra of Pf1 coat protein reconstituted in magnetically aligned bicelles can be significantly improved. This method yields a two-dimensional spin-exchanged version of the SAMPI4 spectrum correlating the (15)N chemical shift and (15)N-(1)H dipolar couplings, as well as spin-correlations between the (i, i ± 1) amide sites. Combining the spin-exchanged SAMPI4 spectrum with the original SAMPI4 experiment makes it possible to establish sequential assignments, and this technique is generally applicable to other uniaxially aligned membrane proteins. Inclusion of an (15)N-(15)N correlation spectrum into the assignment process helps establish correlations between the peaks in crowded or ambiguous spectral regions of the spin-exchanged SAMPI4 experiment. Notably, unlike the traditional method, only a uniformly labeled protein sample is required for spectroscopic assignment with perhaps only a few selectively labeled "seed" spectra. Simulations for the magnetization transfer between the dilute spins under mismatched Hartmann Hahn conditions for various B (1) fields have also been performed. The results adequately describe the optimal conditions for establishing the cross peaks, thus eliminating the need for lengthy experimental optimizations.
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Affiliation(s)
- Wenxing Tang
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, USA
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Non-covalent interaction in metal cation-directed assembly of supramolecular architectures: Synthesis, characterization and crystal structures. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Mote KR, Gopinath T, Traaseth NJ, Kitchen J, Gor'kov PL, Brey WW, Veglia G. Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers. JOURNAL OF BIOMOLECULAR NMR 2011; 51:339-346. [PMID: 21976256 DOI: 10.1007/s10858-011-9571-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/11/2011] [Indexed: 05/31/2023]
Abstract
Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring (1)H-(15)N dipolar couplings (DC) and (15)N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal (rotational) angles of the protein domains can be directly derived from analytical expression of DC and CSA values, or, alternatively, obtained by refining protein structures using these values as harmonic restraints in simulated annealing calculations. The Achilles' heel of this approach is the lack of suitable experiments for sequential assignment of the amide resonances. In this Article, we present a new pulse sequence that integrates proton driven spin diffusion (PDSD) with sensitivity-enhanced PISEMA in a 3D experiment ([(1)H,(15)N]-SE-PISEMA-PDSD). The incorporation of 2D (15)N/(15)N spin diffusion experiments into this new 3D experiment leads to the complete and unambiguous assignment of the (15)N resonances. The feasibility of this approach is demonstrated for the membrane protein sarcolipin reconstituted in magnetically aligned lipid bicelles. Taken with low electric field probe technology, this approach will propel the determination of sequential assignment as well as structure and topology of larger integral membrane proteins in aligned lipid bilayers.
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Affiliation(s)
- Kaustubh R Mote
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455-0431, USA
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Khitrin AK, Xu J, Ramamoorthy A. Cross-correlations between low-γ nuclei in solids via a common dipolar bath. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 212:95-101. [PMID: 21820340 PMCID: PMC3163739 DOI: 10.1016/j.jmr.2011.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/11/2011] [Accepted: 06/18/2011] [Indexed: 05/11/2023]
Abstract
Correlation of chemical shifts of low-γ nuclei (such as 15N) is an important method for assignment of resonances in uniformly-labeled biological solids. Under static experimental conditions, an efficient mixing of low-γ nuclear spin magnetization can be achieved by a thermal contact to the common reservoir of dipole-dipole interactions in order to create 15N-15N, 13C-13C, or 15N-13C cross-peaks in a 2D correlation spectrum. A thermodynamic approach can be used to understand the mechanism of magnetization mixing in various 2D correlation pulse sequences. This mechanism is suppressed under magic-angle spinning, when mixing via direct cross-polarization with protons becomes more efficient. Experimental results are presented for single-crystalline and powder samples of 15N-labeled N-acetyl-L-15N-valyl-L-15N-leucine (NAVL). In addition to the thermodynamic analysis of mixing pulse sequences, two different new mixing sequences utilizing adiabatic pulses are also experimentally demonstrated.
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Affiliation(s)
- Aanatoly K. Khitrin
- Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44240-0001, USA
| | - Jiadi Xu
- Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA
- Corresponding Author: Ayyalusamy Ramamoorthy, , Phone: 734-647-6572
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Lin EC, Opella SJ. 1H assisted 13C/15N heteronuclear correlation spectroscopy in oriented sample solid-state NMR of single crystal and magnetically aligned samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 211:37-44. [PMID: 21543244 PMCID: PMC3236683 DOI: 10.1016/j.jmr.2011.03.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 03/23/2011] [Accepted: 03/29/2011] [Indexed: 05/30/2023]
Abstract
(1)H-irradiation under mismatched Hartmann-Hahn conditions provides an alternative mechanism for carrying out (15)N/(13)C transfers in triple-resonance heteronuclear correlation spectroscopy (HETCOR) on stationary samples of single crystals and aligned samples of biopolymers, which improve the efficiency especially when the direct (15)N-(13)C dipolar couplings are small. In many cases, the sensitivity is improved by taking advantage of the (13)C(α) labeled sites in peptides and proteins with (13)C detection. The similarities between experimental and simulated spectra demonstrate the validity of the recoupling mechanism and identify the potential for applying these experiments to virus particles or membrane proteins in phospholipid bilayers; however, further development is needed in order to derive quantitative distance and angular constraints from these measurements.
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Affiliation(s)
| | - Stanley J. Opella
- Corresponding Author: Stanley J. Opella, , phone 858 822-4820, FAX 858 822-4821
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