1
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Nimerovsky E, Najbauer EÉ, Becker S, Andreas LB. Great Offset Difference Internuclear Selective Transfer. J Phys Chem Lett 2023; 14:3939-3945. [PMID: 37078685 PMCID: PMC10150390 DOI: 10.1021/acs.jpclett.3c00194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Carbon-carbon dipolar recoupling sequences are frequently used building blocks in routine magic-angle spinning NMR experiments. While broadband homonuclear first-order dipolar recoupling sequences mainly excite intra-residue correlations, selective methods can detect inter-residue transfers and long-range correlations. Here, we present the great offset difference internuclear selective transfer (GODIST) pulse sequence optimized for selective carbonyl or aliphatic recoupling at fast magic-angle spinning, here, 55 kHz. We observe a 3- to 5-fold increase in intensities compared with broadband RFDR recoupling for perdeuterated microcrystalline SH3 and for the membrane protein influenza A M2 in lipid bilayers. In 3D (H)COCO(N)H and (H)CO(CO)NH spectra, inter-residue carbonyl-carbonyl correlations up to about 5 Å are observed in uniformly 13C-labeled proteins.
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Affiliation(s)
- Evgeny Nimerovsky
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Eszter Éva Najbauer
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Stefan Becker
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
| | - Loren B Andreas
- Department of NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen 37077, Germany
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2
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Hou Z, Zhan L, Cao K, Luan M, Wang X, Zhang B, Ma L, Yin H, Liu Z, Liu Y, Huang G. Metabolite profiling and identification in living cells by coupling stable isotope tracing and induced electrospray mass spectrometry. Anal Chim Acta 2023; 1241:340795. [PMID: 36657872 DOI: 10.1016/j.aca.2023.340795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/04/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
Direct observation of metabolites in living cells by mass spectrometry offers a bright future for biological studies but also suffers a severe challenge to untargeted peak assignment to tentative metabolite candidates. In this study, we developed a method combining stable isotope tracing and induced electrospray mass spectrometry for living-cells metabolite measurement and identification. By using 13C6-glucose and ammonium chloride-15N as the sole carbon and nitrogen sources for cell culture, Escherichia coli synthesized metabolites with 15N and 13C elements. Tracing the number of carbon and nitrogen atoms could offer a complementary dimension for candidate peak searching. As a result, the identification confidence of metabolites achieved a universal improvement based on carbon/nitrogen labelling and filtration.
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Affiliation(s)
- Zhuanghao Hou
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China.
| | - Liujuan Zhan
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China
| | - Kaiming Cao
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; Department of Pharmacy, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China
| | - Moujun Luan
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China
| | - Xinchen Wang
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China
| | - Buchun Zhang
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China
| | - Likun Ma
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China
| | - Hao Yin
- Mass Spectrometry Lab, Instruments Center for Physical Science, University of Science and Technology of China, 230026, Hefei, China
| | - Zhicheng Liu
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, 81 Meishan Road, 230032, Hefei, China
| | - Yangzhong Liu
- School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China; Department of Pharmacy, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China
| | - Guangming Huang
- Department of Cardiology, The First Affiliated Hospital of USTC, University of Science and Technology of China, 230001, Hefei, China; School of Chemistry and Materials Science, University of Science and Technology of China, 230026, Hefei, China.
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3
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Ahlawat S, Mote KR, Lakomek NA, Agarwal V. Solid-State NMR: Methods for Biological Solids. Chem Rev 2022; 122:9643-9737. [PMID: 35238547 DOI: 10.1021/acs.chemrev.1c00852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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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4
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Liang L, Ji Y, Chen K, Gao P, Zhao Z, Hou G. Solid-State NMR Dipolar and Chemical Shift Anisotropy Recoupling Techniques for Structural and Dynamical Studies in Biological Systems. Chem Rev 2022; 122:9880-9942. [PMID: 35006680 DOI: 10.1021/acs.chemrev.1c00779] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
With the development of NMR methodology and technology during the past decades, solid-state NMR (ssNMR) has become a particularly important tool for investigating structure and dynamics at atomic scale in biological systems, where the recoupling techniques play pivotal roles in modern high-resolution MAS NMR. In this review, following a brief introduction on the basic theory of recoupling in ssNMR, we highlight the recent advances in dipolar and chemical shift anisotropy recoupling methods, as well as their applications in structural determination and dynamical characterization at multiple time scales (i.e., fast-, intermediate-, and slow-motion). The performances of these prevalent recoupling techniques are compared and discussed in multiple aspects, together with the representative applications in biomolecules. Given the recent emerging advances in NMR technology, new challenges for recoupling methodology development and potential opportunities for biological systems are also discussed.
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Affiliation(s)
- Lixin Liang
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Ji
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kuizhi Chen
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Pan Gao
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Zhenchao Zhao
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Guangjin Hou
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
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5
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van der Wel PCA. Dihedral Angle Measurements for Structure Determination by Biomolecular Solid-State NMR Spectroscopy. Front Mol Biosci 2021; 8:791090. [PMID: 34938776 PMCID: PMC8685456 DOI: 10.3389/fmolb.2021.791090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
In structural studies of immobilized, aggregated and self-assembled biomolecules, solid-state NMR (ssNMR) spectroscopy can provide valuable high-resolution structural information. Among the structural restraints provided by magic angle spinning (MAS) ssNMR the canonical focus is on inter-atomic distance measurements. In the current review, we examine the utility of ssNMR measurements of angular constraints, as a complement to distance-based structure determination. The focus is on direct measurements of angular restraints via the judicious recoupling of multiple anisotropic ssNMR parameters, such as dipolar couplings and chemical shift anisotropies. Recent applications are highlighted, with a focus on studies of nanocrystalline polypeptides, aggregated peptides and proteins, receptor-substrate interactions, and small molecule interactions with amyloid protein fibrils. The review also examines considerations of when and where ssNMR torsion angle experiments are (most) effective, and discusses challenges and opportunities for future applications.
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Affiliation(s)
- Patrick C. A. van der Wel
- Solid-state NMR Group, Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
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6
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Gopinath T, Weber DK, Veglia G. Multi-receiver solid-state NMR using polarization optimized experiments (POE) at ultrafast magic angle spinning. JOURNAL OF BIOMOLECULAR NMR 2020; 74:267-285. [PMID: 32333193 PMCID: PMC7236978 DOI: 10.1007/s10858-020-00316-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/11/2020] [Indexed: 05/04/2023]
Abstract
Ultrafast magic angle spinning (MAS) technology and 1H detection have dramatically enhanced the sensitivity of solid-state NMR (ssNMR) spectroscopy of biopolymers. We previously showed that, when combined with polarization optimized experiments (POE), these advancements enable the simultaneous acquisition of multi-dimensional 1H- or 13C-detected experiments using a single receiver. Here, we propose a new sub-class within the POE family, namely HC-DUMAS, HC-MEIOSIS, and HC-MAeSTOSO, that utilize dual receiver technology for the simultaneous detection of 1H and 13C nuclei. We also expand this approach to record 1H-, 13C-, and 15N-detected homonuclear 2D spectra simultaneously using three independent receivers. The combination of POE and multi-receiver technology will further shorten the total experimental time of ssNMR experiments for biological solids.
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Affiliation(s)
- T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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7
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Murray DT, Zhou X, Kato M, Xiang S, Tycko R, McKnight SL. Structural characterization of the D290V mutation site in hnRNPA2 low-complexity-domain polymers. Proc Natl Acad Sci U S A 2018; 115:E9782-E9791. [PMID: 30279180 PMCID: PMC6196502 DOI: 10.1073/pnas.1806174115] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Human genetic studies have given evidence of familial, disease-causing mutations in the analogous amino acid residue shared by three related RNA binding proteins causative of three neurological diseases. Alteration of aspartic acid residue 290 of hnRNPA2 to valine is believed to predispose patients to multisystem proteinopathy. Mutation of aspartic acid 262 of hnRNPA1 to either valine or asparagine has been linked to either amyotrophic lateral sclerosis or multisystem proteinopathy. Mutation of aspartic acid 378 of hnRNPDL to either asparagine or histidine has been associated with limb girdle muscular dystrophy. All three of these aspartic acid residues map to evolutionarily conserved regions of low-complexity (LC) sequence that may function in states of either intrinsic disorder or labile self-association. Here, we present a combination of solid-state NMR spectroscopy with segmental isotope labeling and electron microscopy on the LC domain of the hnRNPA2 protein. We show that, for both the wild-type protein and the aspartic acid 290-to-valine mutant, labile polymers are formed in which the LC domain associates into an in-register cross-β conformation. Aspartic acid 290 is shown to be charged at physiological pH and immobilized within the polymer core. Polymers of the aspartic acid 290-to-valine mutant are thermodynamically more stable than wild-type polymers. These observations give evidence that removal of destabilizing electrostatic interactions may be responsible for the increased propensity of the mutated LC domains to self-associate in disease-causing conformations.
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Affiliation(s)
- Dylan T Murray
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, MD 20892
- Postdoctoral Research Associate Training Program, National Institute of General Medical Sciences, Bethesda, MD 20892
| | - Xiaoming Zhou
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Siheng Xiang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Disease, Bethesda, MD 20892;
| | - Steven L McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390
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8
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Gupta R, Polenova T. Magic angle spinning NMR spectroscopy guided atomistic characterization of structure and dynamics in HIV-1 protein assemblies. Curr Opin Colloid Interface Sci 2018. [DOI: 10.1016/j.cocis.2017.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Murray DT, Kato M, Lin Y, Thurber KR, Hung I, McKnight SL, Tycko R. Structure of FUS Protein Fibrils and Its Relevance to Self-Assembly and Phase Separation of Low-Complexity Domains. Cell 2017; 171:615-627.e16. [PMID: 28942918 PMCID: PMC5650524 DOI: 10.1016/j.cell.2017.08.048] [Citation(s) in RCA: 490] [Impact Index Per Article: 70.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 08/10/2017] [Accepted: 08/25/2017] [Indexed: 12/22/2022]
Abstract
Polymerization and phase separation of proteins containing low-complexity (LC) domains are important factors in gene expression, mRNA processing and trafficking, and localization of translation. We have used solid-state nuclear magnetic resonance methods to characterize the molecular structure of self-assembling fibrils formed by the LC domain of the fused in sarcoma (FUS) RNA-binding protein. From the 214-residue LC domain of FUS (FUS-LC), a segment of only 57 residues forms the fibril core, while other segments remain dynamically disordered. Unlike pathogenic amyloid fibrils, FUS-LC fibrils lack hydrophobic interactions within the core and are not polymorphic at the molecular structural level. Phosphorylation of core-forming residues by DNA-dependent protein kinase blocks binding of soluble FUS-LC to FUS-LC hydrogels and dissolves phase-separated, liquid-like FUS-LC droplets. These studies offer a structural basis for understanding LC domain self-assembly, phase separation, and regulation by post-translational modification.
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Affiliation(s)
- Dylan T Murray
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA; Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892-6200, USA
| | - Masato Kato
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9152, USA
| | - Yi Lin
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9152, USA
| | - Kent R Thurber
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Ivan Hung
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Steven L McKnight
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9152, USA.
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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10
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Quinn CM, Polenova T. Structural biology of supramolecular assemblies by magic-angle spinning NMR spectroscopy. Q Rev Biophys 2017; 50:e1. [PMID: 28093096 PMCID: PMC5483179 DOI: 10.1017/s0033583516000159] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In recent years, exciting developments in instrument technology and experimental methodology have advanced the field of magic-angle spinning (MAS) nuclear magnetic resonance (NMR) to new heights. Contemporary MAS NMR yields atomic-level insights into structure and dynamics of an astounding range of biological systems, many of which cannot be studied by other methods. With the advent of fast MAS, proton detection, and novel pulse sequences, large supramolecular assemblies, such as cytoskeletal proteins and intact viruses, are now accessible for detailed analysis. In this review, we will discuss the current MAS NMR methodologies that enable characterization of complex biomolecular systems and will present examples of applications to several classes of assemblies comprising bacterial and mammalian cytoskeleton as well as human immunodeficiency virus 1 and bacteriophage viruses. The body of work reviewed herein is representative of the recent advancements in the field, with respect to the complexity of the systems studied, the quality of the data, and the significance to the biology.
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Affiliation(s)
- Caitlin M. Quinn
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
| | - Tatyana Polenova
- University of Delaware, Department of Chemistry and Biochemistry, Newark, DE 19711; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, PA 15306
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11
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Tycko R. Molecular Structure of Aggregated Amyloid-β: Insights from Solid-State Nuclear Magnetic Resonance. Cold Spring Harb Perspect Med 2016; 6:a024083. [PMID: 27481836 PMCID: PMC4968170 DOI: 10.1101/cshperspect.a024083] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Amyloid-β (Aβ) peptides aggregate to form polymorphic amyloid fibrils and a variety of intermediate assemblies, including oligomers and protofibrils, both in vitro and in human brain tissue. Since the beginning of the 21st century, considerable progress has been made to characterize the molecular structures of Aβ aggregates. Full molecular structural models based primarily on data from measurements using solid-state nuclear magnetic resonance (ssNMR) have been developed for several in vitro Aβ fibrils and one metastable protofibril. Partial structural characterization of other aggregation intermediates has been achieved. One full structural model for fibrils derived from brain tissue has also been reported. Future work is likely to focus on additional structures from brain tissue and on further clarification of nonfibrillar Aβ aggregates.
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Affiliation(s)
- Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520
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12
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Lu X, Zhang H, Lu M, Vega AJ, Hou G, Polenova T. Improving dipolar recoupling for site-specific structural and dynamics studies in biosolids NMR: windowed RN-symmetry sequences. Phys Chem Chem Phys 2016; 18:4035-44. [PMID: 26776070 DOI: 10.1039/c5cp07818k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Experimental characterization of one-bond heteronuclear dipolar couplings is essential for structural and dynamics characterization of molecules by solid-state NMR. Accurate measurement of heteronuclear dipolar tensor parameters in magic-angle spinning NMR requires that the recoupling sequences efficiently reintroduce the desired heteronuclear dipolar coupling term, fully suppress other interactions (such as chemical shift anisotropy and homonuclear dipolar couplings), and be insensitive to experimental imperfections, such as radio frequency (rf) field mismatch. In this study, we demonstrate that the introduction of window delays into the basic elements of a phase-alternating R-symmetry (PARS) sequence results in a greatly improved protocol, termed windowed PARS (wPARS), which yields clean dipolar lineshapes that are unaffected by other spin interactions and are largely insensitive to experimental imperfections. Higher dipolar scaling factors can be attained in this technique with respect to PARS, which is particularly useful for the measurement of relatively small dipolar couplings. The advantages of wPARS are verified experimentally on model molecules N-acetyl-valine (NAV) and a tripeptide Met-Leu-Phe (MLF). The incorporation of wPARS into 3D heteronuclear or homonuclear correlation experiments permits accurate site-specific determination of dipolar tensors in proteins, as demonstrated on dynein light chain 8 (LC8). Through 3D wPARS recoupling based spectroscopy we have determined both backbone and side chain dipolar tensors in LC8 in a residue-resolved manner. We discuss these in the context of conformational dynamics of LC8. We have addressed the effect of paramagnetic relaxant Cu(ii)-EDTA doping on the dipolar coupling parameters in LC8 and observed no significant differences with respect to the neat sample permitting fast data collection. Our results indicate that wPARS is advantageous with respect to the windowless version of the sequence and is applicable to a broad range of systems including but not limited to biomolecules.
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Affiliation(s)
- Xingyu Lu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
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13
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Nagy-Smith K, Moore E, Schneider J, Tycko R. Molecular structure of monomorphic peptide fibrils within a kinetically trapped hydrogel network. Proc Natl Acad Sci U S A 2015; 112:9816-21. [PMID: 26216960 PMCID: PMC4538636 DOI: 10.1073/pnas.1509313112] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Most, if not all, peptide- and protein-based hydrogels formed by self-assembly can be characterized as kinetically trapped 3D networks of fibrils. The propensity of disease-associated amyloid-forming peptides and proteins to assemble into polymorphic fibrils suggests that cross-β fibrils comprising hydrogels may also be polymorphic. We use solid-state NMR to determine the molecular and supramolecular structure of MAX1, a de novo designed gel-forming peptide, in its fibrillar state. We find that MAX1 adopts a β-hairpin conformation and self-assembles with high fidelity into a double-layered cross-β structure. Hairpins assemble with an in-register Syn orientation within each β-sheet layer and with an Anti orientation between layers. Surprisingly, although the MAX1 fibril network is kinetically trapped, solid-state NMR data show that fibrils within this network are monomorphic and most likely represent the thermodynamic ground state. Intermolecular interactions not available in alternative structural arrangements apparently dictate this monomorphic behavior.
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Affiliation(s)
- Katelyn Nagy-Smith
- Chemical Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21702; Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716
| | - Eric Moore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Joel Schneider
- Chemical Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, MD 21702
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
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14
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Quinn CM, Lu M, Suiter CL, Hou G, Zhang H, Polenova T. Magic angle spinning NMR of viruses. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 86-87:21-40. [PMID: 25919197 PMCID: PMC4413014 DOI: 10.1016/j.pnmrs.2015.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/27/2015] [Accepted: 02/08/2015] [Indexed: 05/02/2023]
Abstract
Viruses, relatively simple pathogens, are able to replicate in many living organisms and to adapt to various environments. Conventional atomic-resolution structural biology techniques, X-ray crystallography and solution NMR spectroscopy provided abundant information on the structures of individual proteins and nucleic acids comprising viruses; however, viral assemblies are not amenable to analysis by these techniques because of their large size, insolubility, and inherent lack of long-range order. In this article, we review the recent advances in magic angle spinning NMR spectroscopy that enabled atomic-resolution analysis of structure and dynamics of large viral systems and give examples of several exciting case studies.
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Affiliation(s)
- Caitlin M Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Manman Lu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Christopher L Suiter
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Guangjin Hou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Huilan Zhang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States.
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
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15
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Suiter CL, Quinn CM, Lu M, Hou G, Zhang H, Polenova T. MAS NMR of HIV-1 protein assemblies. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 253:10-22. [PMID: 25797001 PMCID: PMC4432874 DOI: 10.1016/j.jmr.2014.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/08/2014] [Accepted: 12/17/2014] [Indexed: 06/04/2023]
Abstract
The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.
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Affiliation(s)
- Christopher L Suiter
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Caitlin M Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Manman Lu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Guangjin Hou
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
| | - Huilan Zhang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States.
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States; Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States.
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16
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Zhang R, Nishiyama Y, Sun P, Ramamoorthy A. Phase cycling schemes for finite-pulse-RFDR MAS solid state NMR experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 252:55-66. [PMID: 25655451 PMCID: PMC4380770 DOI: 10.1016/j.jmr.2014.12.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 12/07/2014] [Accepted: 12/17/2014] [Indexed: 05/04/2023]
Abstract
The finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used in 2D homonuclear chemical shift correlation experiments under magic angle spinning (MAS). A recent study demonstrated the advantages of using a short phase cycle, XY4, and its super-cycle, XY4(1)4, for the fp-RFDR pulse sequence employed in 2D (1)H/(1)H single-quantum/single-quantum correlation experiments under ultrafast MAS conditions. In this study, we report a comprehensive analysis on the dipolar recoupling efficiencies of XY4, XY4(1)2, XY4(1)3, XY4(1)4, and XY8(1)4 phase cycles under different spinning speeds ranging from 10 to 100 kHz. The theoretical calculations reveal the presence of second-order terms (T(10)T(2,±2), T(1,±1)T(2,±1), etc.) in the recoupled homonuclear dipolar coupling Hamiltonian only when the basic XY4 phase cycle is utilized, making it advantageous for proton-proton magnetization transfer under ultrafast MAS conditions. It is also found that the recoupling efficiency of fp-RFDR is quite dependent on the duty factor (τ180/τR) as well as on the strength of homonuclear dipolar couplings. The rate of longitudinal magnetization transfer increases linearly with the duty factor of fp-RFDR for all the XY-based phase cycles investigated in this study. Examination of the performances of different phase cycles against chemical shift offset and RF field inhomogeneity effects revealed that XY4(1)4 is the most tolerant phase cycle, while the shortest phase cycle XY4 suppressed the RF field inhomogeneity effects most efficiently under slow spinning speeds. Our results suggest that the difference in the fp-RFDR recoupling efficiencies decreases with the increasing MAS speed, while ultrafast (>60 kHz) spinning speed is advantageous as it recouples a large amount of homonuclear dipolar couplings and therefore enable fast magnetization exchange. The effects of higher-order terms and cross terms between various interactions in the effective Hamiltonian of fp-RFDR are also analyzed using numerical simulations for various phase cycles. Results obtained via numerical simulations are in excellent agreement with ultrafast MAS experimental results from the powder samples of glycine and l-alanine.
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Affiliation(s)
- Rongchun Zhang
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
| | - Yusuke Nishiyama
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan; RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan
| | - Pingchuan Sun
- Key Laboratory of Functional Polymer Materials of Ministry of Education and College of Chemistry, Nankai University, Tianjin 300071, PR China
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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17
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Nishiyama Y, Malon M, Ishii Y, Ramamoorthy A. 3D ¹⁵N/¹⁵N/¹H chemical shift correlation experiment utilizing an RFDR-based ¹H/¹H mixing period at 100 kHz MAS. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 244:1-5. [PMID: 24801998 PMCID: PMC4062578 DOI: 10.1016/j.jmr.2014.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/29/2014] [Accepted: 04/07/2014] [Indexed: 05/04/2023]
Abstract
Homonuclear correlation NMR experiments are commonly used in the high-resolution structural studies of proteins. While (13)C/(13)C chemical shift correlation experiments utilizing dipolar recoupling techniques are fully utilized under MAS, correlation of the chemical shifts of (15)N nuclei in proteins has been a challenge. Previous studies have shown that the negligible (15)N-(15)N dipolar coupling in peptides or proteins necessitates the use of a very long mixing time (typically several seconds) for effective spin diffusion to occur and considerably slows down a (15)N/(15)N correlation experiment. In this study, we show that the use of mixing proton magnetization, instead of (15)N, via the recoupled (1)H-(1)H dipolar couplings enable faster (15)N/(15)N correlation. In addition, the use of proton-detection under ultrafast MAS overcomes the sensitivity loss due to multiple magnetization transfer (between (1)H and (15)N nuclei) steps. In fact, less than 300 nL (∼1.1 micromole quantity) sample is sufficient to acquire the 3D spectrum within 5 h. Our results also demonstrate that a 3D (15)N/(15)N/(1)H experiment can render higher resolution spectra that will be useful in the structural studies of proteins at ultrafast MAS frequencies. 3D (15)N/(15)N/(1)H and 2D radio frequency-driven dipolar recoupling (RFDR)-based (1)H/(1)H experimental results obtained from a powder sample of N-acetyla-L-(15)N-valyl-L-(15)N-leucine at 70 and 100kHz MAS frequencies are presented.
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Affiliation(s)
| | - Michal Malon
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Yuji Ishii
- JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 196-8558, Japan
| | - Ayyalusamy Ramamoorthy
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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18
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Bayro MJ, Chen B, Yau WM, Tycko R. Site-specific structural variations accompanying tubular assembly of the HIV-1 capsid protein. J Mol Biol 2013; 426:1109-27. [PMID: 24370930 DOI: 10.1016/j.jmb.2013.12.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
Abstract
The 231-residue capsid (CA) protein of human immunodeficiency virus type 1 (HIV-1) spontaneously self-assembles into tubes with a hexagonal lattice that is believed to mimic the surface lattice of conical capsid cores within intact virions. We report the results of solid-state nuclear magnetic resonance (NMR) measurements on HIV-1 CA tubes that provide new information regarding changes in molecular structure that accompany CA self-assembly, local dynamics within CA tubes, and possible mechanisms for the generation of lattice curvature. This information is contained in site-specific assignments of signals in two- and three-dimensional solid-state NMR spectra, conformation-dependent (15)N and (13)C NMR chemical shifts, detection of highly dynamic residues under solution NMR conditions, measurements of local variations in transverse spin relaxation rates of amide (1)H nuclei, and quantitative measurements of site-specific (15)N-(15)N dipole-dipole couplings. Our data show that most of the CA sequence is conformationally ordered and relatively rigid in tubular assemblies and that structures of the N-terminal domain (NTD) and the C-terminal domain (CTD) observed in solution are largely retained. However, specific segments, including the N-terminal β-hairpin, the cyclophilin A binding loop, the inter-domain linker, segments involved in intermolecular NTD-CTD interactions, and the C-terminal tail, have substantial static or dynamical disorder in tubular assemblies. Other segments, including the 310-helical segment in CTD, undergo clear conformational changes. Structural variations associated with curvature of the CA lattice appear to be localized in the inter-domain linker and intermolecular NTD-CTD interface, while structural variations within NTD hexamers, around local 3-fold symmetry axes, and in CTD-CTD dimerization interfaces are less significant.
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Affiliation(s)
- Marvin J Bayro
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Bo Chen
- Department of Physics, University of Central Florida, Orlando, FL 32816, USA
| | - Wai-Ming Yau
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | - Robert Tycko
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
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19
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Lu JX, Qiang W, Yau WM, Schwieters CD, Meredith SC, Tycko R. Molecular structure of β-amyloid fibrils in Alzheimer's disease brain tissue. Cell 2013; 154:1257-68. [PMID: 24034249 DOI: 10.1016/j.cell.2013.08.035] [Citation(s) in RCA: 866] [Impact Index Per Article: 78.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/11/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
Abstract
In vitro, β-amyloid (Aβ) peptides form polymorphic fibrils, with molecular structures that depend on growth conditions, plus various oligomeric and protofibrillar aggregates. Here, we investigate structures of human brain-derived Aβ fibrils, using seeded fibril growth from brain extract and data from solid-state nuclear magnetic resonance and electron microscopy. Experiments on tissue from two Alzheimer's disease (AD) patients with distinct clinical histories showed a single predominant 40 residue Aβ (Aβ40) fibril structure in each patient; however, the structures were different from one another. A molecular structural model developed for Aβ40 fibrils from one patient reveals features that distinguish in-vivo- from in-vitro-produced fibrils. The data suggest that fibrils in the brain may spread from a single nucleation site, that structural variations may correlate with variations in AD, and that structure-specific amyloid imaging agents may be an important future goal.
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Affiliation(s)
- Jun-Xia Lu
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
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20
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Qiang W, Tycko R. Zero-quantum stochastic dipolar recoupling in solid state nuclear magnetic resonance. J Chem Phys 2013; 137:104201. [PMID: 22979851 DOI: 10.1063/1.4749258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the theoretical description and experimental demonstration of a zero-quantum stochastic dipolar recoupling (ZQ-SDR) technique for solid state nuclear magnetic resonance (NMR) studies of (13)C-labeled molecules, including proteins, under magic-angle spinning (MAS). The ZQ-SDR technique combines zero-quantum recoupling pulse sequence blocks with randomly varying chemical shift precession periods to create randomly amplitude- and phase-modulated effective homonuclear magnetic dipole-dipole couplings. To a good approximation, couplings between different (13)C spin pairs become uncorrelated under ZQ-SDR, leading to spin dynamics (averaged over many repetitions of the ZQ-SDR sequence) that are fully described by an orientation-dependent N × N polarization transfer rate matrix for an N-spin system, with rates that are inversely proportional to the sixth power of internuclear distances. Suppression of polarization transfers due to non-commutivity of pairwise couplings (i.e., dipolar truncation) does not occur under ZQ-SDR, as we show both analytically and numerically. Experimental demonstrations are reported for uniformly (13)C-labeled L-valine powder (at 14.1 T and 28.00 kHz MAS), uniformly (13)C-labeled protein GB1 in microcrystalline form (at 17.6 T and 40.00 kHz MAS), and partially labeled (13)C-labeled protein GB1 (at 14.1 T and 40.00 kHz MAS). The experimental results verify that spin dynamics under ZQ-SDR are described accurately by rate matrices and suggest the utility of ZQ-SDR in structural studies of (13)C-labeled solids.
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Affiliation(s)
- Wei Qiang
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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21
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Bermejo GA, Clore GM, Schwieters CD. Smooth statistical torsion angle potential derived from a large conformational database via adaptive kernel density estimation improves the quality of NMR protein structures. Protein Sci 2012; 21:1824-36. [PMID: 23011872 DOI: 10.1002/pro.2163] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 09/14/2012] [Accepted: 09/17/2012] [Indexed: 11/09/2022]
Abstract
Statistical potentials that embody torsion angle probability densities in databases of high-quality X-ray protein structures supplement the incomplete structural information of experimental nuclear magnetic resonance (NMR) datasets. By biasing the conformational search during the course of structure calculation toward highly populated regions in the database, the resulting protein structures display better validation criteria and accuracy. Here, a new statistical torsion angle potential is developed using adaptive kernel density estimation to extract probability densities from a large database of more than 10⁶ quality-filtered amino acid residues. Incorporated into the Xplor-NIH software package, the new implementation clearly outperforms an older potential, widely used in NMR structure elucidation, in that it exhibits simultaneously smoother and sharper energy surfaces, and results in protein structures with improved conformation, nonbonded atomic interactions, and accuracy.
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Affiliation(s)
- Guillermo A Bermejo
- Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892-5624, USA
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22
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McDonald M, Box H, Bian W, Kendall A, Tycko R, Stubbs G. Fiber diffraction data indicate a hollow core for the Alzheimer's aβ 3-fold symmetric fibril. J Mol Biol 2012; 423:454-61. [PMID: 22903058 DOI: 10.1016/j.jmb.2012.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 07/11/2012] [Accepted: 08/09/2012] [Indexed: 10/28/2022]
Abstract
Amyloid β protein (Aβ), the principal component of the extracellular plaques found in the brains of patients with Alzheimer's disease, forms fibrils well suited to structural study by X-ray fiber diffraction. Fiber diffraction patterns from the 40-residue form Aβ(1-40) confirm a number of features of a 3-fold symmetric Aβ model from solid-state NMR (ssNMR) but suggest that the fibrils have a hollow core not present in the original ssNMR models. Diffraction patterns calculated from a revised 3-fold hollow model with a more regular β-sheet structure are in much better agreement with the observed diffraction data than patterns calculated from the original ssNMR model. Refinement of a hollow-core model against ssNMR data led to a revised ssNMR model, similar to the fiber diffraction model.
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Affiliation(s)
- Michele McDonald
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235-1634, USA
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