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Kasai T, Ono S, Koshiba S, Yamamoto M, Tanaka T, Ikeda S, Kigawa T. Amino-acid selective isotope labeling enables simultaneous overlapping signal decomposition and information extraction from NMR spectra. JOURNAL OF BIOMOLECULAR NMR 2020; 74:125-137. [PMID: 32002710 PMCID: PMC7080692 DOI: 10.1007/s10858-019-00295-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Signal overlapping is a major bottleneck for protein NMR analysis. We propose a new method, stable-isotope-assisted parameter extraction (SiPex), to resolve overlapping signals by a combination of amino-acid selective isotope labeling (AASIL) and tensor decomposition. The basic idea of Sipex is that overlapping signals can be decomposed with the help of intensity patterns derived from quantitative fractional AASIL, which also provides amino-acid information. In SiPex, spectra for protein characterization, such as 15N relaxation measurements, are assembled with those for amino-acid information to form a four-order tensor, where the intensity patterns from AASIL contribute to high decomposition performance even if the signals share similar chemical shift values or characterization profiles, such as relaxation curves. The loading vectors of each decomposed component, corresponding to an amide group, represent both the amino-acid and relaxation information. This information link provides an alternative protein analysis method that does not require "assignments" in a general sense; i.e., chemical shift determinations, since the amino-acid information for some of the residues allows unambiguous assignment according to the dual selective labeling. SiPex can also decompose signals in time-domain raw data without Fourier transform, even in non-uniformly sampled data without spectral reconstruction. These features of SiPex should expand biological NMR applications by overcoming their overlapping and assignment problems.
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Affiliation(s)
- Takuma Kasai
- Laboratory for Cellular Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan.
- PRESTO, JST, Kawaguchi, Japan.
| | - Shunsuke Ono
- PRESTO, JST, Kawaguchi, Japan
- School of Computing, Tokyo Institute of Technology, Yokohama, Japan
| | - Seizo Koshiba
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Masayuki Yamamoto
- Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Toshiyuki Tanaka
- Department of Systems Science, Graduate School of Informatics, Kyoto University, Kyoto, Japan
| | - Shiro Ikeda
- Department of Statistical Inference and Mathematics, The Institute of Statistical Mathematics, Tachikawa, Japan
| | - Takanori Kigawa
- Laboratory for Cellular Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan.
- School of Computing, Tokyo Institute of Technology, Yokohama, Japan.
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2
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Stetz MA, Caro JA, Kotaru S, Yao X, Marques BS, Valentine KG, Wand AJ. Characterization of Internal Protein Dynamics and Conformational Entropy by NMR Relaxation. Methods Enzymol 2018; 615:237-284. [PMID: 30638531 PMCID: PMC6364297 DOI: 10.1016/bs.mie.2018.09.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Recent studies suggest that the fast timescale motion of methyl-bearing side chains may play an important role in mediating protein activity. These motions have been shown to encapsulate the residual conformational entropy of the folded state that can potentially contribute to the energetics of protein function. Here, we provide an overview of how to characterize these motions using nuclear magnetic resonance (NMR) spin relaxation methods. The strengths and limitations of several techniques are highlighted in order to assist with experimental design. Particular emphasis is placed on the practical aspects of sample preparation, data collection, data fitting, and statistical analysis. Additionally, discussion of the recently refined "entropy meter" is presented and its use in converting NMR observables to conformational entropy is illustrated. Taken together, these methods should yield new insights into the complex interplay between structure and dynamics in protein function.
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Affiliation(s)
- Matthew A Stetz
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - José A Caro
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Sravya Kotaru
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Xuejun Yao
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Bryan S Marques
- Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Kathleen G Valentine
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - A Joshua Wand
- Johnson Research Foundation and Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Graduate Group in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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3
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Srb P, Nováček J, Kadeřávek P, Rabatinová A, Krásný L, Žídková J, Bobálová J, Sklenář V, Žídek L. Triple resonance ¹⁵Ν NMR relaxation experiments for studies of intrinsically disordered proteins. JOURNAL OF BIOMOLECULAR NMR 2017; 69:133-146. [PMID: 29071460 DOI: 10.1007/s10858-017-0138-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 09/26/2017] [Indexed: 06/07/2023]
Abstract
Description of protein dynamics is known to be essential in understanding their function. Studies based on a well established [Formula: see text] NMR relaxation methodology have been applied to a large number of systems. However, the low dispersion of [Formula: see text] chemical shifts very often observed within intrinsically disordered proteins complicates utilization of standard 2D HN correlated spectra because a limited number of amino acids can be characterized. Here we present a suite of triple resonance HNCO-type NMR experiments for measurements of five [Formula: see text] relaxation parameters ([Formula: see text], [Formula: see text], NOE, cross-correlated relaxation rates [Formula: see text] and [Formula: see text]) in doubly [Formula: see text],[Formula: see text]-labeled proteins. We show that the third spectral dimension combined with non-uniform sampling provides relaxation rates for almost all residues of a protein with extremely poor chemical shift dispersion, the C terminal domain of [Formula: see text]-subunit of RNA polymerase from Bacillus subtilis. Comparison with data obtained using a sample labeled by [Formula: see text] only showed that the presence of [Formula: see text] has a negligible effect on [Formula: see text], [Formula: see text], and on the cross-relaxation rate (calculated from NOE and [Formula: see text]), and that these relaxation rates can be used to calculate accurate spectral density values. Partially [Formula: see text]-labeled sample was used to test if the observed increase of [Formula: see text] [Formula: see text] in the presence of [Formula: see text] corresponds to the [Formula: see text] dipole-dipole interactions in the [Formula: see text],[Formula: see text]-labeled sample.
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Affiliation(s)
- Pavel Srb
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí, 542/2, 166 10, Praha 6, Czech Republic
| | - Jiří Nováček
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Pavel Kadeřávek
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Alžbeta Rabatinová
- Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic v.v.i., Videňská 1083, 142 20, Prague, Czech Republic
| | - Libor Krásný
- Laboratory of Molecular Genetics of Bacteria, Institute of Microbiology, Academy of Sciences of the Czech Republic v.v.i., Videňská 1083, 142 20, Prague, Czech Republic
| | - Jitka Žídková
- Institute of Analytical Chemistry of the Czech Academy of Sciences v.v.i., Veveří 97, 602 00, Brno, Czech Republic
| | - Janette Bobálová
- Institute of Analytical Chemistry of the Czech Academy of Sciences v.v.i., Veveří 97, 602 00, Brno, Czech Republic
| | - Vladimír Sklenář
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Lukáš Žídek
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
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4
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Yi HA, Fochtman BC, Rizzo RC, Jacobs A. Inhibition of HIV Entry by Targeting the Envelope Transmembrane Subunit gp41. Curr HIV Res 2016; 14:283-94. [PMID: 26957202 DOI: 10.2174/1570162x14999160224103908] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 09/23/2015] [Accepted: 09/30/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND The transmembrane subunit of the HIV envelope protein, gp41 is a vulnerable target to inhibit HIV entry. There is one fusion inhibitor T20 (brand name: Fuzeon, generic name: enfuvirtide) available by prescription. However, it has several drawbacks such as a high level of development of drug resistance, a short-half life in vivo, rapid renal clearance, low oral bioavailability, and it is only used as a salvage therapy. Therefore, investigators have been studying a variety of different modalities to attempt to overcome these limitations. METHODS Comprehensive literature searches were performed on HIV gp41, inhibition mechanisms, and inhibitors. The latest structural information was collected, and multiple inhibition strategies targeting gp41 were reviewed. RESULTS Many of the recent advances in inhibitors were peptide-based. Several creative modification strategies have also been performed to improve inhibitory efficacy of peptides and to overcome the drawbacks of T20 treatment. Small compounds have also been an area of intense research. There is a wide variety in development from those identified by virtual screens targeting specific regions of the protein to natural products. Finally, broadly neutralizing antibodies have also been important area of research. The inaccessible nature of the target regions for antibodies is a challenge, however, extensive efforts to develop better neutralizing antibodies are ongoing. CONCLUSION The fusogenic protein, gp41 has been extensively studied as a promising target to inhibit membrane fusion between the virus and target cells. At the same time, it is a challenging target because the vulnerable conformations of the protein are exposed only transiently. However, advances in biochemical, biophysical, structural, and immunological studies are coming together to move the field closer to an understanding of gp41 structure and function that will lead to the development of novel drugs and vaccines.
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Affiliation(s)
| | | | | | - Amy Jacobs
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA.
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5
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Lakomek NA, Kaufman JD, Stahl SJ, Louis JM, Grishaev A, Wingfield PT, Bax A. Internal dynamics of the homotrimeric HIV-1 viral coat protein gp41 on multiple time scales. Angew Chem Int Ed Engl 2013; 52:3911-5. [PMID: 23450638 PMCID: PMC3610801 DOI: 10.1002/anie.201207266] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 02/01/2013] [Indexed: 02/02/2023]
Affiliation(s)
- Nils-Alexander Lakomek
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Building 5, Room 126, 9000 Rockville Pike, Bethesda, MD 20892-0520, USA
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6
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Lakomek NA, Kaufman JD, Stahl SJ, Louis JM, Grishaev A, Wingfield PT, Bax A. Internal Dynamics of the Homotrimeric HIV-1 Viral Coat Protein gp41 on Multiple Time Scales. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201207266] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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7
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Chill JH, Naider F. A solution NMR view of protein dynamics in the biological membrane. Curr Opin Struct Biol 2011; 21:627-33. [PMID: 21807499 DOI: 10.1016/j.sbi.2011.07.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/25/2011] [Accepted: 07/11/2011] [Indexed: 11/26/2022]
Abstract
Structure determination of membrane-associated proteins (MPs) represents a frontier of structural biology that is characterized by unique challenges in sample preparation and data acquisition. No less important is our ability to study the dynamics of MPs, since MP flexibility and characteristic motions often make sizeable contributions to their function. This review focuses on solution state NMR methods to characterize dynamics of MPs in the membrane environment. NMR approaches to study molecular motions on a wide range of time-scales and their application to membrane proteins are described. Studies of polytopic and bitopic MPs demonstrating the power of such methods to characterize the dynamic behavior of MPs and their interaction with the membrane-mimicking surroundings are presented. Attempts are made to place the dynamic conclusions into a biological context. The importance and limitations of such investigations guarantee that further developments in this field will be actively pursued.
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Affiliation(s)
- Jordan H Chill
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel.
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8
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Fast-time scale dynamics of outer membrane protein A by extended model-free analysis of NMR relaxation data. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:68-76. [PMID: 19665446 DOI: 10.1016/j.bbamem.2009.07.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 07/22/2009] [Indexed: 11/20/2022]
Abstract
In order to better understand the dynamics of an integral membrane protein, backbone amide (15)N NMR dynamics measurements of the beta-barrel membrane protein OmpA have been performed at three magnetic fields. A total of nine relaxation data sets were globally analyzed using an extended model-free formalism. The diffusion tensor was found to be prolate axially symmetric with an axial ratio of 5.75, indicating a possible rotation of the protein within the micelle. The generalized order parameters gradually decreased from the mid-plane towards the two ends of the barrel, counteracting the dynamic gradient of the lipids in a matching bilayer, and were dramatically reduced in the extracellular loops. Large-scale internal motions on the ns time scale indicate that entire loops most likely undergo concerted ("sea anemone"-like) motions emanating from their anchoring points on the barrel. The case of OmpA in DPC micelles also illustrates inherent limitations of analyzing the data with even the most sophisticated current models of the model-free formalism. It is likely that conformational exchange processes on the ms-mus also play a role in describing the motions of some residues, but their analysis did not produce unique results that could be independently verified.
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9
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Chen K, Tjandra N. Direct measurements of protein backbone 15N spin relaxation rates from peak line-width using a fully-relaxed Accordion 3D HNCO experiment. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:71-6. [PMID: 19114314 PMCID: PMC2647993 DOI: 10.1016/j.jmr.2008.12.001] [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: 08/07/2008] [Revised: 11/14/2008] [Accepted: 12/03/2008] [Indexed: 05/11/2023]
Abstract
Protein backbone (15)N spin relaxation rates measured by solution NMR provide useful dynamic information with a site-specific resolution. The conventional method is to record a series of 2D (1)H-(15)N HSQC spectra with varied relaxation delays, and derive relaxation rate from the following curve fitting on the resonance intensities. Proteins with poorly resolved spectra often require several 3D HNCO spectra to be collected on a (15)N/(13)C double labeled protein sample. In order to reduce the relaxation dimension Carr et al. (P.A. Carr, D.A. Fearing, A.G. Palmer, 3D accordion spectroscopy for measuring N-15 and (CO)-Carbon-13 relaxation rates in poorly resolved NMR spectra, J. Magn. Reson. 132 (1998) 25-33) employed an Accordion type HNCO pulse sequence to obtain (15)N or (13)C T(1) relaxation rates by numerical fitting of the relaxation interfered free induction decay (FID) data. To avoid intensive analysis of the time domain data, we propose a modified protocol to measure (15)N T(1) and T(2) relaxation rates from easily obtained line-widths in an Accordion HNCO spectrum. Both T(1) and T(2) relaxation could be simultaneously convoluted into the constant-time evolution periods of (13)C' and (15)N, respectively. The relaxation delay was allowed to reach at least 3 x T(1) or 3 x T(2) so that the signal was substantially decayed by the end of the FID, and the resulting peak full-width at half height (FWHH) could be directly used to calculate relaxation rate. When applied to the 76-residue Ubiquitin and the 226-residue glutamine-binding protein (GlnBP), this method yielded T(1) and T(2) values deviating on average by 4-6% and 5-7%, respectively, from the measurements based on the conventional 2D method. In comparison, the conventional methods possessed intrinsic error ranges of 2-4% for T(1) and 3-6% for T(2). In addition to comparable accuracy, the fully-relaxed Accordion HNCO method presented here allowed measurements of relaxation rates for resonances unresolved in 2D spectra, thus providing a more complete dynamic picture of the protein.
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Affiliation(s)
| | - Nico Tjandra
- To whom correspondence should be addressed: Building 50, Room 3503, NHLBI, NIH, Bethesda, MD 20892, Phone: (301) 402-3029, Fax: (301) 402-3405,
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10
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Burnley BT, Kalverda AP, Paisey SJ, Berry A, Homans SW. Hadamard NMR spectroscopy for relaxation measurements of large (>35 kDa) proteins. JOURNAL OF BIOMOLECULAR NMR 2007; 39:239-45. [PMID: 17882509 DOI: 10.1007/s10858-007-9192-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 08/31/2007] [Indexed: 05/17/2023]
Abstract
Here we present a suite of pulse sequences for the measurement of (15)N T(1), T(1rho) and NOE data that combine traditional TROSY-based pulse sequences with band-selective Hadamard frequency encoding. The additive nature of the Hadamard matrix produces much reduced resonance overlap without the need for an increase in the dimensionality of the experiment or a significant decrease in the signal to noise ratio. We validate the accuracy of these sequences in application to ubiquitin and demonstrate their utility for relaxation measurements in Escherichia coli Class II fructose 1,6-bisphosphate aldolase (FBP-aldolase), a 358 residue 78 kDa dimeric enzyme.
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Affiliation(s)
- B Tom Burnley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
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11
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Eliseo T, Ragona L, Catalano M, Assfalg M, Paci M, Zetta L, Molinari H, Cicero DO. Structural and dynamic determinants of ligand binding in the ternary complex of chicken liver bile acid binding protein with two bile salts revealed by NMR. Biochemistry 2007; 46:12557-67. [PMID: 17929837 DOI: 10.1021/bi7013085] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bile acids are physiological detergents facilitating absorption, transport, and distribution of lipid-soluble vitamins and dietary fats;they also play a role as signaling molecules that activate nuclear receptors and regulate cholesterol metabolism. Bile acid circulation is mediated by bile acid binding proteins (BABPs), and a detailed structural study of the complex of BABPs with bile salts has become a key issue for the complete understanding of the role of these proteins and their involvement in cholesterol homeostasis. The solution structure here reported describes, at variance with previously determined singly ligated structures, a BABP in a ternary complex with two bile acid molecules, obtained by employing a variety of NMR experiments. Exchange processes between the two bound chenodeoxycholate molecules as well as the more superficial ligand and the free pool have been detected through ROESY and diffusion experiments. Significant backbone flexibility has been observed in regions located at the protein open end, facilitating bile salts exchange. A detailed description of the protonation states and tautomeric forms of histidines strongly supports the view that histidine protonation modulates backbone flexibility and regulates ligand binding. This structure opens the way to targeted site-directed mutagenesis and interaction studies to investigate both binding and nuclear localization mechanisms.
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Affiliation(s)
- Tommaso Eliseo
- NMR Laboratory, Department of Chemical Science and Technology, University of Rome Tor Vergata, 00133 Roma, Italy
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12
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Chill JH, Louis JM, Baber JL, Bax A. Measurement of 15N relaxation in the detergent-solubilized tetrameric KcsA potassium channel. JOURNAL OF BIOMOLECULAR NMR 2006; 36:123-36. [PMID: 17013683 DOI: 10.1007/s10858-006-9071-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 07/26/2006] [Indexed: 05/12/2023]
Abstract
A set of TROSY-HNCO (tHNCO)-based 3D experiments is presented for measuring (15)N relaxation parameters in large, membrane-associated proteins, characterized by slow tumbling times and significant spectral overlap. Measurement of backbone (15)N R (1), R (1rho), (15)N-{(1)H} NOE, and (15)N CSA/dipolar cross correlation is demonstrated and applied to study the dynamic behavior of the homotetrameric KcsA potassium channel in SDS micelles under conditions where this channel is in the closed state. The micelle-encapsulated transmembrane domain, KcsA(TM), exhibits a high degree of order, tumbling as an oblate ellipsoid with a global rotational correlation time, tau(c) = 38 +/- 2.5 ns, at 50 degrees C and a diffusion anisotropy, Dparallel/Dperpendicular = 0.79+/-0.05, corresponding to an aspect ratio a/b >/= 1.4. The N- and C-terminal intracellular segments of KcsA exhibit considerable internal dynamics (S (2) values in the 0.2-0.45 range), but are distinctly more ordered than what has been observed for unstructured random coils. Relaxation behavior in these domains confirms the position of the C-terminal helix, and indicates that in SDS micelles, this amphiphilic helix does not associate into a stable homotetrameric helical bundle. The relaxation data indicate the absence of elevated backbone dynamics on the ps-ns time scale for the 5-residue selectivity filter, which selects K(+) ions to enter the channel.
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Affiliation(s)
- Jordan H Chill
- Laboratory of Chemical Physics, NIDDK, National Institutes of Health, Building 5, Room 126, 9000 Rockville Pike, Bethesda, Maryland 20892, USA
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13
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McFeeters RL, Fowler CA, Gaponenko VV, Byrd RA. Efficient and precise measurement of H(alpha)-C(alpha), C(alpha)-C', C(alpha)-C(beta) and H(N)-N residual dipolar couplings from 2D H(N)-N correlation spectra. JOURNAL OF BIOMOLECULAR NMR 2005; 31:35-47. [PMID: 15692737 DOI: 10.1007/s10858-004-6057-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Accepted: 10/18/2004] [Indexed: 05/24/2023]
Abstract
A suite of experiments are presented for the measurement of H(alpha)-C(alpha), C(alpha)-C', C(alpha)-C(beta) and H(N)-N couplings from uniformly 15N, 13C labeled proteins. Couplings are obtained from a series of intensity modulated two-dimensional H(N)-N spectra equivalent to the common 1H-15N-HSQC spectra, alleviating many overlap and assignment issues associated with other techniques. To illustrate the efficiency of this method, H(alpha)-C(alpha), C(alpha)-C', and H(N)-N isotropic scalar couplings were determined for ubiquitin from data collected in less than 4.5 h, C(alpha)-C(beta) data collection required 10 h. The resulting couplings were measured with an average error of +/-0.06, +/-0.05, +/-0.04 and +/-0.10 Hz, respectively. This study also shows H(alpha)-C(alpha) and C(alpha)-C(beta) couplings, valuable because they provide orientation of bond vectors outside the peptide plane, can be measured in a uniform and precise way. Superior accuracy and precision to existing 3D measurements for C(alpha)-C' couplings and increased precision compared to IPAP measurements for H(N)-N couplings are demonstrated. Minor modifications allow for acquisition of modulated H(N)-C' 2D spectra, which can yield additional well resolved peaks and significantly increase the number of measured RDCs for proteins with crowded 1H-15N resonances.
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Affiliation(s)
- Robert L McFeeters
- Macromolecular NMR Section, Structural Biophysics Laboratory, National Cancer Institute, Frederick, MD 21702, USA
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14
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Tugarinov V, Choy WY, Kupce E, Kay LE. Addressing the overlap problem in the quantitative analysis of two dimensional NMR spectra: application to (15)N relaxation measurements. JOURNAL OF BIOMOLECULAR NMR 2004; 30:347-352. [PMID: 15756461 DOI: 10.1007/s10858-005-1549-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Accepted: 07/09/2004] [Indexed: 05/24/2023]
Abstract
A quantitative analysis of 2D (1)H-(15)N spectra is often complicated by resonance overlap. Here a simple method is presented for resolving overlapped correlations by recording 2D projection planes from HNCO data sets. Applications are presented involving the measurement of (15)N T(1rho) relaxation rates in a high molecular weight protein, malate synthase G, and in a system that exchanges between folded and unfolded states, the drkN SH3 domain. By supplementing relaxation data recorded in the conventional way as a series of 2D (1)H-(15)N data sets with a series of a pair of projection planes the number of dynamics probes is increased significantly for both systems studied.
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Affiliation(s)
- Vitali Tugarinov
- Protein Engineering Network Centres of Excellence and the Departments of Medical Genetics, Biochemistry and Chemistry, University of Toronto, M5S lA8, Toronto, Ontario, Canada
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15
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Pang Y, Buck M, Zuiderweg ERP. Backbone dynamics of the ribonuclease binase active site area using multinuclear ((15)N and (13)CO) NMR relaxation and computational molecular dynamics. Biochemistry 2002; 41:2655-66. [PMID: 11851412 DOI: 10.1021/bi011657f] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The nano-pico second backbone dynamics of the ribonuclease binase, homologous to barnase, is investigated with (15)N, (13)C NMR relaxation at 11.74 and 18.78 T and with a 1.1 ns molecular dynamics simulation. The data are compared with the temperature factors reported for the X-ray structure of this enzyme. The molecular dynamics and X-ray data correspond well and predict motions in the loops 56-61 and 99-104 that contain residues that specifically recognize substrate and are catalytic (His101), respectively. In contrast, the (15)N relaxation data indicate that these loops are mostly ordered at the nano-pico second time scale. Nano-pico second motions in the recognition loop 56-61 are evident from (13)CO-(13)C cross relaxation data, but the mobility of the catalytic loop 99-104 is not detected by (13)CO cross relaxation either. From the results of this and previous work [Wang, L., Pang, Y., Holder, T., Brender, J. R., Kurochkin, A., and Zuiderweg, E. R. P. (2001) Proc. Natl. Acad. Sci. U.S.A., 98, 7684-7689], the following dynamical characterization of the active site area of binase emerges: a beta sheet, rigid at all probed time scales, supports the catalytic residue Glu 72. Both substrate-encapsulating loops are mobile on both fast and slow time scales, but the fast motions of the loop which contains the other catalytic residue, His 101, as predicted by B-factors and computational molecular dynamics is not detected by NMR relaxation. This work strongly argues for the use of several measures in the study of protein dynamics.
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Affiliation(s)
- Yuxi Pang
- Department of Biological Chemistry, University of Michigan, Biophysics Research Division, Ann Arbor, Michigan 48109-1055, USA
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Caffrey M. Model for the structure of the HIV gp41 ectodomain: insight into the intermolecular interactions of the gp41 loop. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1536:116-22. [PMID: 11406346 DOI: 10.1016/s0925-4439(01)00042-4] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In human immunodeficiency virus (HIV) the viral envelope proteins gp41 and gp120 form a non-covalent complex, which is a potential target for AIDS therapies. In addition gp41 plays a possible role in HIV infection of B cells via the complement system. In an effort to better understand the molecular interactions of gp41, the structure of the HIV gp41 ectodomain has been modeled using the NMR restraints of the simian immunodeficiency virus (SIV) gp41 ectodomain (M. Caffrey, M. Cai, J. Kaufman, S.J. Stahl, P.T. Wingfield, A.M. Gronenborn, G.M. Clore, Solution structure of the 44 kDa ectodomain of SIV gp41, EMBO J. 17 (1998) 4572--4584). The resulting model presents the first structural information for the HIV gp41 loop, which has been implicated to play a direct role in binding to gp120 and C1q of the complement system.
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Affiliation(s)
- M Caffrey
- Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Caffrey M, Kaufman J, Stahl S, Wingfield P, Gronenborn AM, Clore GM. Monomer-trimer equilibrium of the ectodomain of SIV gp41: insight into the mechanism of peptide inhibition of HIV infection. Protein Sci 1999; 8:1904-7. [PMID: 10493592 PMCID: PMC2144406 DOI: 10.1110/ps.8.9.1904] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The monomer-trimer equilibrium of the ectodomain of SIV gp41 (residues 27-149, e-gp41) has been characterized by analytical ultracentrifugation, circular dichroism (CD), and NMR spectroscopy. Based on analytical ultracentrifugation experiments performed at different rotor speeds and protein concentrations, the equilibrium association constant for the SIV e-gp41 trimer is 3.1 x 10(11) M(-2). The presence of intermolecular nuclear Overhauser effects in a mixture of 12C and 13C-labeled e-gp41 prepared under nondenaturing conditions unambiguously demonstrates that there is a dynamic equilibrium between the monomer and trimer. The CD spectra taken as a function of SIV e-gp41 concentration suggest that the helical content of the monomeric state does not change significantly relative to that of the trimeric state. The relevance of the monomer-trimer equilibrium is discussed with respect to gp41 function and the inhibitory properties of gp41 peptides.
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Affiliation(s)
- M Caffrey
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892-0520, USA
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