1
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Zhang J, Li H, Zhao X, Wu Q, Huang SY. Holo Protein Conformation Generation from Apo Structures by Ligand Binding Site Refinement. J Chem Inf Model 2022; 62:5806-5820. [PMID: 36342197 DOI: 10.1021/acs.jcim.2c00895] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
An important part in structure-based drug design is the selection of an appropriate protein structure. It has been revealed that a holo protein structure that contains a well-defined binding site is a much better choice than an apo structure in structure-based drug discovery. Therefore, it is valuable to obtain a holo-like protein conformation from apo structures in the case where no holo structure is available. Meeting the need, we present a robust approach to generate reliable holo-like structures from apo structures by ligand binding site refinement with restraints derived from holo templates with low homology. Our method was tested on a test set of 32 proteins from the DUD-E data set and compared with other approaches. It was shown that our method successfully refined the apo structures toward the corresponding holo conformations for 23 of 32 proteins, reducing the average all-heavy-atom RMSD of binding site residues by 0.48 Å. In addition, when evaluated against all the holo structures in the protein data bank, our method can improve the binding site RMSD for 14 of 19 cases that experience significant conformational changes. Furthermore, our refined structures also demonstrate their advantages over the apo structures in ligand binding mode predictions by both rigid docking and flexible docking and in virtual screening on the database of active and decoy ligands from the DUD-E. These results indicate that our method is effective in recovering holo-like conformations and will be valuable in structure-based drug discovery.
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Affiliation(s)
- Jinze Zhang
- School of Physics, Huazhong University of Science and Technology, Wuhan430074, Hubei, P. R. China
| | - Hao Li
- School of Physics, Huazhong University of Science and Technology, Wuhan430074, Hubei, P. R. China
| | - Xuejun Zhao
- School of Physics, Huazhong University of Science and Technology, Wuhan430074, Hubei, P. R. China
| | - Qilong Wu
- School of Physics, Huazhong University of Science and Technology, Wuhan430074, Hubei, P. R. China
| | - Sheng-You Huang
- School of Physics, Huazhong University of Science and Technology, Wuhan430074, Hubei, P. R. China
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2
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Chinnam NB, Syed A, Hura GL, Hammel M, Tainer JA, Tsutakawa SE. Combining small angle X-ray scattering (SAXS) with protein structure predictions to characterize conformations in solution. Methods Enzymol 2022; 678:351-376. [PMID: 36641214 PMCID: PMC10132260 DOI: 10.1016/bs.mie.2022.09.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Accurate protein structure predictions, enabled by recent advances in machine learning algorithms, provide an entry point to probing structural mechanisms and to integrating and querying many types of biochemical and biophysical results. Limitations in such protein structure predictions can be reduced and addressed through comparison to experimental Small Angle X-ray Scattering (SAXS) data that provides protein structural information in solution. SAXS data can not only validate computational predictions, but can improve conformational and assembly prediction to produce atomic models that are consistent with solution data and biologically relevant states. Here, we describe how to obtain protein structure predictions, compare them to experimental SAXS data and improve models to reflect experimental information from SAXS data. Furthermore, we consider the potential for such experimentally-validated protein structure predictions to broadly improve functional annotation in proteins identified in metagenomics and to identify functional clustering on conserved sites despite low sequence homology.
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Affiliation(s)
- Naga Babu Chinnam
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Aleem Syed
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Greg L Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, United States
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Susan E Tsutakawa
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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3
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Structural interpretations of a flexible cold-active AMS8 lipase by combining small-angle X-ray scattering and molecular dynamics simulation (SAXS-MD). Int J Biol Macromol 2022; 220:1095-1103. [PMID: 36029961 DOI: 10.1016/j.ijbiomac.2022.08.145] [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: 06/03/2022] [Revised: 07/25/2022] [Accepted: 08/22/2022] [Indexed: 11/22/2022]
Abstract
Determining structure of highly flexible protein with multiple conformations can be challenging. This paper aims to combine molecular dynamics (MD) and small angle X-ray diffraction (SAX) techniques as a solution to overcome issues related to protein conformation in hardly crystallized protein. Based on prior studies, a cold-active lipase AMS8 was simulated in solvents showing stability in its N-terminal and high flexibility in its C-terminal. However, MD in its own algorithm could not explain the basis of macromolecule conformational transitions or changes related to protein through folding. Hence, by combining SAXS with MD, it is possible to understand the structure of flexible AMS8 lipase in natural space. Based on the findings, SAXS ab-initio model of AMS8 lipase was identified as a monomeric protein in which the optimized model of cold-active lipase AMS8 derived from SAXS data was found to be aligned with AMS8 homology model under series of MD timeframe.
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4
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Choudhary P, Badmalia MD, Rao A. Shape-function insights into bifunctional O-GlcNActransferase of Listeria monocytogenes EGD-e. Glycobiology 2020; 31:275-287. [PMID: 32776104 DOI: 10.1093/glycob/cwaa076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/13/2022] Open
Abstract
O-GlcNAcylation is an important post-translational modification of proteins. O-GlcNAcylated proteins have crucial roles in several cellular contexts both in eukaryotes and bacteria. O-GlcNActransferase (OGT) is the enzyme instrumental in O-GlcNAcylation of proteins. OGT is conserved across eukaryotes. The first bacterial OGT discovered is GmaR in Listeria monocytogenes. GmaR is a GT-2 family bifunctional protein that catalyzes glycosylation of the flagellin protein FlaA and controls transcription of flagellar motility genes in a temperature-dependent manner. Here, we provide methods for heterologous expression and purification of recombinant GmaR and FlaA, in vivo/in vitro glycosylation assays, analysis of the molecular form of recombinant GmaR and detailed enzyme kinetics. We study the structure and functional dynamics of GmaR. Using solution small-angle X-ray scattering and molecular modeling, we show that GmaR adopts an extended shape with two distinctly spaced structural units in the presence of cofactor Mg2+ and with donor UDP-GlcNAc and cofactor combined. Comparisons of restored structures revealed that in-solution binding of Mg2+ ions brings about shape rearrangements and induces structural-rigidity in hyper-variable regions at the N-terminus of GmaR protein. Taking function and shape data together, we describe that Mg2+ binding enables GmaR to adopt a shape that can bind the substrate. The manuscript provides the first 3D solution structure of a bacterial OGT of GT-2 family and detailed biochemical characterization of GmaR to facilitate its future applications.
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Affiliation(s)
| | - Maulik D Badmalia
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | | | - Alka Rao
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India.,Academy of Scientific and Innovation Research (AcSIR), Sector 19, Kamla Nehru Nagar, Ghaziabad 201002, India
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5
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Hou J, Adhikari B, Tanner JJ, Cheng J. SAXSDom: Modeling multidomain protein structures using small-angle X-ray scattering data. Proteins 2020; 88:775-787. [PMID: 31860156 PMCID: PMC7230021 DOI: 10.1002/prot.25865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/18/2019] [Accepted: 12/14/2019] [Indexed: 12/27/2022]
Abstract
Many proteins are composed of several domains that pack together into a complex tertiary structure. Multidomain proteins can be challenging for protein structure modeling, particularly those for which templates can be found for individual domains but not for the entire sequence. In such cases, homology modeling can generate high quality models of the domains but not for the orientations between domains. Small-angle X-ray scattering (SAXS) reports the structural properties of entire proteins and has the potential for guiding homology modeling of multidomain proteins. In this article, we describe a novel multidomain protein assembly modeling method, SAXSDom that integrates experimental knowledge from SAXS with probabilistic Input-Output Hidden Markov model to assemble the structures of individual domains together. Four SAXS-based scoring functions were developed and tested, and the method was evaluated on multidomain proteins from two public datasets. Incorporation of SAXS information improved the accuracy of domain assembly for 40 out of 46 critical assessment of protein structure prediction multidomain protein targets and 45 out of 73 multidomain protein targets from the ab initio domain assembly dataset. The results demonstrate that SAXS data can provide useful information to improve the accuracy of domain-domain assembly. The source code and tool packages are available at https://github.com/jianlin-cheng/SAXSDom.
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Affiliation(s)
- Jie Hou
- Department of Computer Science, Saint Louis University, St. Louis, MO, 63103, USA
| | - Badri Adhikari
- Department of Computer Science, University of Missouri-St. Louis, Saint Louis, MO 63121, USA
| | - John J. Tanner
- Departments of Biochemistry and Chemistry, University of Missouri, Columbia, MO, 65211, USA
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA
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6
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Liu S, Xiang X, Gao X, Liu H. Neighborhood Preference of Amino Acids in Protein Structures and its Applications in Protein Structure Assessment. Sci Rep 2020; 10:4371. [PMID: 32152349 PMCID: PMC7062742 DOI: 10.1038/s41598-020-61205-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 02/24/2020] [Indexed: 12/02/2022] Open
Abstract
Amino acids form protein 3D structures in unique manners such that the folded structure is stable and functional under physiological conditions. Non-specific and non-covalent interactions between amino acids exhibit neighborhood preferences. Based on structural information from the protein data bank, a statistical energy function was derived to quantify amino acid neighborhood preferences. The neighborhood of one amino acid is defined by its contacting residues, and the energy function is determined by the neighboring residue types and relative positions. The neighborhood preference of amino acids was exploited to facilitate structural quality assessment, which was implemented in the neighborhood preference program NEPRE. The source codes are available via https://github.com/LiuLab-CSRC/NePre.
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Affiliation(s)
- Siyuan Liu
- Complex Systems Division, Beijing Computational Science Research Center, Haidian, Beijing, 100193, China
- School of Software Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Xilun Xiang
- Complex Systems Division, Beijing Computational Science Research Center, Haidian, Beijing, 100193, China
- School of Software Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Xiang Gao
- Complex Systems Division, Beijing Computational Science Research Center, Haidian, Beijing, 100193, China
- School of Software Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China
| | - Haiguang Liu
- Complex Systems Division, Beijing Computational Science Research Center, Haidian, Beijing, 100193, China.
- Physics Department, Beijing Normal University, Haidian, Beijing, 100875, China.
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7
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An ensemble of flexible conformations underlies mechanotransduction by the cadherin-catenin adhesion complex. Proc Natl Acad Sci U S A 2019; 116:21545-21555. [PMID: 31591245 PMCID: PMC6815173 DOI: 10.1073/pnas.1911489116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Adherens junctions are specialized cell–cell adhesion complexes found in epithelial, endothelial, and neuronal tissues of multicellular organism. The cadherin–catenin complex is the core component of the adherens junction and transmits mechanical stress from cell to cell. This study reveals that the cadherin–catenin complex displays a wide spectrum of flexible structures, which suggests a dynamic mechanism for this complex in mechanotransduction for cell–cell adhesion. The cadherin–catenin adhesion complex is the central component of the cell–cell adhesion adherens junctions that transmit mechanical stress from cell to cell. We have determined the nanoscale structure of the adherens junction complex formed by the α-catenin•β-catenin•epithelial cadherin cytoplasmic domain (ABE) using negative stain electron microscopy, small-angle X-ray scattering, and selective deuteration/small-angle neutron scattering. The ABE complex is highly pliable and displays a wide spectrum of flexible structures that are facilitated by protein-domain motions in α- and β-catenin. Moreover, the 107-residue intrinsically disordered N-terminal segment of β-catenin forms a flexible “tongue” that is inserted into α-catenin and participates in the assembly of the ABE complex. The unanticipated ensemble of flexible conformations of the ABE complex suggests a dynamic mechanism for sensitivity and reversibility when transducing mechanical signals, in addition to the catch/slip bond behavior displayed by the ABE complex under mechanical tension. Our results provide mechanistic insight into the structural dynamics for the cadherin–catenin adhesion complex in mechanotransduction.
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8
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Zheng W, Zhang C, Bell EW, Zhang Y. I-TASSER gateway: A protein structure and function prediction server powered by XSEDE. FUTURE GENERATIONS COMPUTER SYSTEMS : FGCS 2019; 99:73-85. [PMID: 31427836 PMCID: PMC6699767 DOI: 10.1016/j.future.2019.04.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
There is an increasing gap between the number of known protein sequences and the number of proteins with experimentally characterized structure and function. To alleviate this issue, we have developed the I-TASSER gateway, an online server for automated and reliable protein structure and function prediction. For a given sequence, I-TASSER starts with template recognition from a known structure library, followed by full-length atomic model construction by iterative assembly simulations of the continuous structural fragments excised from the template alignments. Functional insights are then derived from comparative matching of the predicted model with a library of proteins with known function. The I-TASSER pipeline has been recently integrated with the XSEDE Gateway system to accommodate pressing demand from the user community and increasing computing costs. This report summarizes the configuration of the I-TASSER Gateway with the XSEDE-Comet supercomputer cluster, together with an overview of the I-TASSER method and milestones of its development.
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9
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Nicholl ID, Matsui T, Weiss TM, Stanley CB, Heller WT, Martel A, Farago B, Callaway DJE, Bu Z. α-Catenin Structure and Nanoscale Dynamics in Solution and in Complex with F-Actin. Biophys J 2018; 115:642-654. [PMID: 30037495 DOI: 10.1016/j.bpj.2018.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/17/2018] [Accepted: 07/05/2018] [Indexed: 12/26/2022] Open
Abstract
As a core component of the adherens junction, α-catenin stabilizes the cadherin/catenin complexes to the actin cytoskeleton for the mechanical coupling of cell-cell adhesion. α-catenin also modulates actin dynamics, cell polarity, and cell-migration functions that are independent of the adherens junction. We have determined the solution structures of the α-catenin monomer and dimer using in-line size-exclusion chromatography small-angle X-ray scattering, as well as the structure of α-catenin dimer in complex to F-actin filament using selective deuteration and contrast-matching small angle neutron scattering. We further present the first observation, to our knowledge, of the nanoscale dynamics of α-catenin by neutron spin-echo spectroscopy, which explicitly reveals the mobile regions of α-catenin that are crucial for binding to F-actin. In solution, the α-catenin monomer is more expanded than either protomer shown in the crystal structure dimer, with the vinculin-binding M fragment and the actin-binding domain being able to adopt different configurations. The α-catenin dimer in solution is also significantly more expanded than the dimer crystal structure, with fewer interdomain and intersubunit contacts than the crystal structure. When in complex to F-actin, the α-catenin dimer has an even more open and extended conformation than in solution, with the actin-binding domain further separated from the main body of the dimer. The α-catenin-assembled F-actin bundle develops into an ordered filament packing arrangement at increasing α-catenin/F-actin molar ratios. Together, the structural and dynamic studies reveal that α-catenin possesses dynamic molecular conformations that prime this protein to function as a mechanosensor protein.
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Affiliation(s)
- Iain D Nicholl
- Department of Biomedical Science and Physiology, Faculty of Science and Engineering, University of Wolverhampton, Wolverhampton, United Kingdom
| | - Tsutomu Matsui
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | - Thomas M Weiss
- Stanford Synchrotron Radiation Light Source, Menlo Park, California
| | | | - William T Heller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | | | | | - David J E Callaway
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
| | - Zimei Bu
- Department of Chemistry and Biochemistry, City College of New York, City University of New York, New York, New York.
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10
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Recent developments in small-angle X-ray scattering and hybrid method approaches for biomacromolecular solutions. Emerg Top Life Sci 2018; 2:69-79. [PMID: 33525782 DOI: 10.1042/etls20170138] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 02/01/2018] [Accepted: 02/05/2018] [Indexed: 01/05/2023]
Abstract
Small-angle X-ray scattering (SAXS) has become a streamline method to characterize biological macromolecules, from small peptides to supramolecular complexes, in near-native solutions. Modern SAXS requires limited amounts of purified material, without the need for labelling, crystallization, or freezing. Dedicated beamlines at modern synchrotron sources yield high-quality data within or below several milliseconds of exposure time and are highly automated, allowing for rapid structural screening under different solutions and ambient conditions but also for time-resolved studies of biological processes. The advanced data analysis methods allow one to meaningfully interpret the scattering data from monodisperse systems, from transient complexes as well as flexible and heterogeneous systems in terms of structural models. Especially powerful are hybrid approaches utilizing SAXS with high-resolution structural techniques, but also with biochemical, biophysical, and computational methods. Here, we review the recent developments in the experimental SAXS practice and in analysis methods with a specific focus on the joint use of SAXS with complementary methods.
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11
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Henriques J, Arleth L, Lindorff-Larsen K, Skepö M. On the Calculation of SAXS Profiles of Folded and Intrinsically Disordered Proteins from Computer Simulations. J Mol Biol 2018; 430:2521-2539. [PMID: 29548755 DOI: 10.1016/j.jmb.2018.03.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 03/02/2018] [Accepted: 03/02/2018] [Indexed: 11/15/2022]
Abstract
Solution techniques such as small-angle X-ray scattering (SAXS) play a central role in structural studies of intrinsically disordered proteins (IDPs); yet, due to low resolution, it is generally necessary to combine SAXS with additional experimental sources of data and to use molecular simulations. Computational methods for the calculation of theoretical SAXS intensity profiles can be separated into two groups, depending on whether the solvent is modeled implicitly as continuous electron density or considered explicitly. The former offers reduced computational cost but requires the definition of a number of free parameters to account for, for example, the excess density of the solvation layer. Overfitting can thus be an issue, particularly when the structural ensemble is unknown. Here, we investigate and show how small variations of the contrast of the hydration shell, δρ, severely affect the outcome, analysis and interpretation of computed SAXS profiles for folded and disordered proteins. For both the folded and disordered proteins studied here, using a default δρ may, in some cases, result in the calculation of non-representative SAXS profiles, leading to an overestimation of their size and a misinterpretation of their structural nature. The solvation layer of the different IDP simulations also impacts their size estimates differently, depending on the protein force field used. The same is not true for the folded protein simulations, suggesting differences in the solvation of the two classes of proteins, and indicating that different force fields optimized for IDPs may cause expansion of the polypeptide chain through different physical mechanisms.
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Affiliation(s)
- João Henriques
- Division of Theoretical Chemistry, Department of Chemistry, Lund University, Kemicentrum, PO Box 124, S-221 00 Lund, Sweden; Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Lise Arleth
- Structural Biophysics, Section for Neutron and X-ray Science, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory & Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Marie Skepö
- Division of Theoretical Chemistry, Department of Chemistry, Lund University, Kemicentrum, PO Box 124, S-221 00 Lund, Sweden.
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12
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Summers TJ, Cheng Q, DeYonker NJ. A transition state “trapped”? QM-cluster models of engineered threonyl-tRNA synthetase. Org Biomol Chem 2018; 16:4090-4100. [DOI: 10.1039/c8ob00540k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
QM-cluster models demonstrate how protein bioengineering alters the local energy landscape of p-biphenylalanine to stabilize a transition state analogue.
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Affiliation(s)
| | - Qianyi Cheng
- The Department of Chemistry
- The University of Memphis
- Memphis
- USA
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13
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Hybrid Methods for Modeling Protein Structures Using Molecular Dynamics Simulations and Small-Angle X-Ray Scattering Data. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1105:237-258. [PMID: 30617833 DOI: 10.1007/978-981-13-2200-6_15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Small-angle X-ray scattering (SAXS) is an efficient experimental tool to measure the overall shape of macromolecular structures in solution. However, due to the low resolution of SAXS data, high-resolution data obtained from X-ray crystallography or NMR and computational methods such as molecular dynamics (MD) simulations are complementary to SAXS data for understanding protein functions based on their structures at atomic resolution. Because MD simulations provide a physicochemically proper structural ensemble for flexible proteins in solution and a precise description of solvent effects, the hybrid analysis of SAXS and MD simulations is a promising method to estimate reasonable solution structures and structural ensembles in solution. Here, we review typical and useful in silico methods for modeling three dimensional protein structures, calculating theoretical SAXS profiles, and analyzing ensemble structures consistent with experimental SAXS profiles. We also review two examples of the hybrid analysis, termed MD-SAXS method in which MD simulations are carried out without any knowledge of experimental SAXS data, and the experimental SAXS data are used only to assess the consistency of the solution model from MD simulations with those observed in experiments. One example is an investigation of the intrinsic dynamics of EcoO109I using the computational method to obtain a theoretical profile from the trajectory of an MD simulation. The other example is a structural investigation of the vitamin D receptor ligand-binding domain using snapshots generated by MD simulations and assessment of the snapshots by experimental SAXS data.
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14
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Bernadó P, Shimizu N, Zaccai G, Kamikubo H, Sugiyama M. Solution scattering approaches to dynamical ordering in biomolecular systems. Biochim Biophys Acta Gen Subj 2017; 1862:253-274. [PMID: 29107147 DOI: 10.1016/j.bbagen.2017.10.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 01/09/2023]
Abstract
Clarification of solution structure and its modulation in proteins and protein complexes is crucially important to understand dynamical ordering in macromolecular systems. Small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS) are among the most powerful techniques to derive structural information. Recent progress in sample preparation, instruments and software analysis is opening up a new era for small-angle scattering. In this review, recent progress and trends of SAXS and SANS are introduced from the point of view of instrumentation and analysis, touching on general features and standard methods of small-angle scattering. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.
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Affiliation(s)
- Pau Bernadó
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, France
| | - Nobutaka Shimizu
- Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Giuseppe Zaccai
- Institut Laue Langevin, Institut de Biologie Structurale, CNRS, CNRS, UGA, Grenoble, France
| | - Hironari Kamikubo
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
| | - Masaaki Sugiyama
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan..
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15
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Cheng Q, Joung I, Lee J. A Simple and Efficient Protein Structure Refinement Method. J Chem Theory Comput 2017; 13:5146-5162. [PMID: 28800396 DOI: 10.1021/acs.jctc.7b00470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Improving the quality of a given protein structure can serve as the ultimate solution for accurate protein structure prediction, and seeking such a method is currently a challenge in computational structural biology. In order to promote and encourage much needed such efforts, CASP (Critical Assessment of Structure Prediction) has been providing an ideal computational experimental platform, where it was reported only recently (since CASP10) that systematic protein structure refinement is possible by carrying out extensive (approximately millisecond) MD simulations with proper restraints generated from the given structure. Using an explicit solvent model and much reduced positional and distance restraints than previously exercised, we propose a refinement protocol that combines a series of short (5 ns) MD simulations with energy minimization procedures. Testing and benchmarking on 54 CASP8-10 refinement targets and 34 CASP11 refinement targets shows quite promising results. Using only a small fraction of MD simulation steps (nanosecond versus millisecond), systematic protein structure refinement was demonstrated in this work, indicating that refinement of a given model can be achieved using a few hours of desktop computing.
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Affiliation(s)
- Qianyi Cheng
- Center for In Silico Protein Science and School of Computational Sciences, Korea Institute for Advanced Study , Seoul 02455, Korea
| | - InSuk Joung
- Center for In Silico Protein Science and School of Computational Sciences, Korea Institute for Advanced Study , Seoul 02455, Korea
| | - Jooyoung Lee
- Center for In Silico Protein Science and School of Computational Sciences, Korea Institute for Advanced Study , Seoul 02455, Korea
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16
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Trewhella J, Duff AP, Durand D, Gabel F, Guss JM, Hendrickson WA, Hura GL, Jacques DA, Kirby NM, Kwan AH, Pérez J, Pollack L, Ryan TM, Sali A, Schneidman-Duhovny D, Schwede T, Svergun DI, Sugiyama M, Tainer JA, Vachette P, Westbrook J, Whitten AE. 2017 publication guidelines for structural modelling of small-angle scattering data from biomolecules in solution: an update. Acta Crystallogr D Struct Biol 2017; 73:710-728. [PMID: 28876235 PMCID: PMC5586245 DOI: 10.1107/s2059798317011597] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/07/2017] [Indexed: 12/02/2022] Open
Abstract
In 2012, preliminary guidelines were published addressing sample quality, data acquisition and reduction, presentation of scattering data and validation, and modelling for biomolecular small-angle scattering (SAS) experiments. Biomolecular SAS has since continued to grow and authors have increasingly adopted the preliminary guidelines. In parallel, integrative/hybrid determination of biomolecular structures is a rapidly growing field that is expanding the scope of structural biology. For SAS to contribute maximally to this field, it is essential to ensure open access to the information required for evaluation of the quality of SAS samples and data, as well as the validity of SAS-based structural models. To this end, the preliminary guidelines for data presentation in a publication are reviewed and updated, and the deposition of data and associated models in a public archive is recommended. These guidelines and recommendations have been prepared in consultation with the members of the International Union of Crystallography (IUCr) Small-Angle Scattering and Journals Commissions, the Worldwide Protein Data Bank (wwPDB) Small-Angle Scattering Validation Task Force and additional experts in the field.
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Affiliation(s)
- Jill Trewhella
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Anthony P. Duff
- ANSTO, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Bâtiment 430, Université Paris-Sud, 91405 Orsay CEDEX, France
| | - Frank Gabel
- Université Grenoble Alpes, Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Structurale (IBS), and Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - J. Mitchell Guss
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Greg L. Hura
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - David A. Jacques
- University of Technology Sydney, ithree Institute, 15 Broadway, Ultimo, NSW 2007, Australia
| | - Nigel M. Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Ann H. Kwan
- School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Javier Pérez
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-sur-Yvette CEDEX, France
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853-2501, USA
| | - Timothy M. Ryan
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences (QB3), University of California San Francisco, San Francisco, California, USA
| | - Dina Schneidman-Duhovny
- School of Computer Science and Engineering, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Torsten Schwede
- Biozentrum, University of Basel and SIB Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL) Hamburg, c/o DESY, Nokestrasse 85, 22607 Hamburg, Germany
| | - Masaaki Sugiyama
- Research Reactor Institute, Kyoto University, Kumatori, Sennan-gun, Osaka 590-0494, Japan
| | - John A. Tainer
- Basic Science Research Division, Molecular and Cellular Oncology, MD Anderson Cancer Center, University of Texas, Houston, Texas, USA
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Bâtiment 430, Université Paris-Sud, 91405 Orsay CEDEX, France
| | - John Westbrook
- Department of Chemistry and Chemical Biology, Rutgers University, New Brunswick, NJ 07102, USA
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17
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Machado ATP, Fonseca EMB, Reis MAD, Saraiva AM, Santos CAD, de Toledo MAS, Polikarpov I, de Souza AP, Aparicio R, Iulek J. Conformational variability of the stationary phase survival protein E from Xylella fastidiosa revealed by X-ray crystallography, small-angle X-ray scattering studies, and normal mode analysis. Proteins 2017; 85:1931-1943. [PMID: 28677327 DOI: 10.1002/prot.25347] [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: 01/10/2017] [Revised: 06/07/2017] [Accepted: 07/02/2017] [Indexed: 11/05/2022]
Abstract
Xylella fastidiosa is a xylem-limited bacterium that infects a wide variety of plants. Stationary phase survival protein E is classified as a nucleotidase, which is expressed when bacterial cells are in the stationary growth phase and subjected to environmental stresses. Here, we report four refined X-ray structures of this protein from X. fastidiosa in four different crystal forms in the presence and/or absence of the substrate 3'-AMP. In all chains, the conserved loop verified in family members assumes a closed conformation in either condition. Therefore, the enzymatic mechanism for the target protein might be different of its homologs. Two crystal forms exhibit two monomers whereas the other two show four monomers in the asymmetric unit. While the biological unit has been characterized as a tetramer, differences of their sizes and symmetry are remarkable. Four conformers identified by Small-Angle X-ray Scattering (SAXS) in a ligand-free solution are related to the low frequency normal modes of the crystallographic structures associated with rigid body-like protomer arrangements responsible for the longitudinal and symmetric adjustments between tetramers. When the substrate is present in solution, only two conformers are selected. The most prominent conformer for each case is associated to a normal mode able to elongate the protein by moving apart two dimers. To our knowledge, this work was the first investigation based on the normal modes that analyzed the quaternary structure variability for an enzyme of the SurE family followed by crystallography and SAXS validation. The combined results raise new directions to study allosteric features of XfSurE protein.
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Affiliation(s)
| | | | - Marcelo Augusto Dos Reis
- Institute of Chemistry, University of Campinas, São Paulo, Brazil.,Federal Institute of Education, Science and Technology of South of Minas Gerais, Inconfidentes, Minas Gerais, Brazil
| | - Antonio Marcos Saraiva
- Molecular Biology and Genetic Engineering Centre, University of Campinas, São Paulo, Brazil
| | | | | | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos, São Paulo, Brazil
| | - Anete Pereira de Souza
- Molecular Biology and Genetic Engineering Centre, University of Campinas, São Paulo, Brazil.,Department of Plant Biology, Biology Institute, University of Campinas, São Paulo, Brazil
| | - Ricardo Aparicio
- Institute of Chemistry, University of Campinas, São Paulo, Brazil
| | - Jorge Iulek
- Department of Chemistry, State University of Ponta Grossa, Brazil
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18
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Tuukkanen AT, Kleywegt GJ, Svergun DI. Resolution of ab initio shapes determined from small-angle scattering. IUCRJ 2016; 3:440-447. [PMID: 27840683 PMCID: PMC5094446 DOI: 10.1107/s2052252516016018] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/10/2016] [Indexed: 05/31/2023]
Abstract
Spatial resolution is an important characteristic of structural models, and the authors of structures determined by X-ray crystallography or electron cryo-microscopy always provide the resolution upon publication and deposition. Small-angle scattering of X-rays or neutrons (SAS) has recently become a mainstream structural method providing the overall three-dimensional structures of proteins, nucleic acids and complexes in solution. However, no quantitative resolution measure is available for SAS-derived models, which significantly hampers their validation and further use. Here, a method is derived for resolution assessment for ab initio shape reconstruction from scattering data. The inherent variability of the ab initio shapes is utilized and it is demonstrated how their average Fourier shell correlation function is related to the model resolution. The method is validated against simulated data for proteins with known high-resolution structures and its efficiency is demonstrated in applications to experimental data. It is proposed that henceforth the resolution be reported in publications and depositions of ab initio SAS models.
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Affiliation(s)
- Anne T. Tuukkanen
- EMBL Hamburg c/o DESY, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
- European Bioinformatics Institute (EMBL–EBI), European Molecular Biology Laboratory, Welcome Genome Campus, Hinxton, Cambridge CB10 1SD, England
| | - Gerard J. Kleywegt
- European Bioinformatics Institute (EMBL–EBI), European Molecular Biology Laboratory, Welcome Genome Campus, Hinxton, Cambridge CB10 1SD, England
| | - Dmitri I. Svergun
- EMBL Hamburg c/o DESY, European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
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19
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Yang K, Różycki B, Cui F, Shi C, Chen W, Li Y. Sampling Enrichment toward Target Structures Using Hybrid Molecular Dynamics-Monte Carlo Simulations. PLoS One 2016; 11:e0156043. [PMID: 27227775 PMCID: PMC4881967 DOI: 10.1371/journal.pone.0156043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/09/2016] [Indexed: 01/08/2023] Open
Abstract
Sampling enrichment toward a target state, an analogue of the improvement of sampling efficiency (SE), is critical in both the refinement of protein structures and the generation of near-native structure ensembles for the exploration of structure-function relationships. We developed a hybrid molecular dynamics (MD)-Monte Carlo (MC) approach to enrich the sampling toward the target structures. In this approach, the higher SE is achieved by perturbing the conventional MD simulations with a MC structure-acceptance judgment, which is based on the coincidence degree of small angle x-ray scattering (SAXS) intensity profiles between the simulation structures and the target structure. We found that the hybrid simulations could significantly improve SE by making the top-ranked models much closer to the target structures both in the secondary and tertiary structures. Specifically, for the 20 mono-residue peptides, when the initial structures had the root-mean-squared deviation (RMSD) from the target structure smaller than 7 Å, the hybrid MD-MC simulations afforded, on average, 0.83 Å and 1.73 Å in RMSD closer to the target than the parallel MD simulations at 310K and 370K, respectively. Meanwhile, the average SE values are also increased by 13.2% and 15.7%. The enrichment of sampling becomes more significant when the target states are gradually detectable in the MD-MC simulations in comparison with the parallel MD simulations, and provide >200% improvement in SE. We also performed a test of the hybrid MD-MC approach in the real protein system, the results showed that the SE for 3 out of 5 real proteins are improved. Overall, this work presents an efficient way of utilizing solution SAXS to improve protein structure prediction and refinement, as well as the generation of near native structures for function annotation.
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Affiliation(s)
- Kecheng Yang
- Key Laboratory of Synthetic Rubber & Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02–668, Warsaw, Poland
| | - Fengchao Cui
- Key Laboratory of Synthetic Rubber & Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China
- * E-mail: (FC); (YL)
| | - Ce Shi
- Key Laboratory of Synthetic Rubber & Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China
| | - Wenduo Chen
- Key Laboratory of Synthetic Rubber & Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China
| | - Yunqi Li
- Key Laboratory of Synthetic Rubber & Laboratory of Advanced Power Sources, Changchun Institute of Applied Chemistry (CIAC), Chinese Academy of Sciences, Changchun, 130022, P. R. China
- * E-mail: (FC); (YL)
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20
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Joo K, Joung I, Cheng Q, Lee SJ, Lee J. Contact-assisted protein structure modeling by global optimization in CASP11. Proteins 2016; 84 Suppl 1:189-99. [DOI: 10.1002/prot.24975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 11/24/2015] [Accepted: 12/12/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Keehyoung Joo
- Center for in Silico Protein Science, Korea Institute for Advanced Study; Seoul 130-722 Korea
- Center for Advanced Computation, Korea Institute for Advanced Study; Seoul 130-722 Korea
| | - InSuk Joung
- Center for in Silico Protein Science, Korea Institute for Advanced Study; Seoul 130-722 Korea
- School of Computational Sciences, Korea Institute for Advanced Study; Seoul 130-722 Korea
| | - Qianyi Cheng
- Center for in Silico Protein Science, Korea Institute for Advanced Study; Seoul 130-722 Korea
- School of Computational Sciences, Korea Institute for Advanced Study; Seoul 130-722 Korea
| | - Sung Jong Lee
- Center for in Silico Protein Science, Korea Institute for Advanced Study; Seoul 130-722 Korea
- Department of Physics; University of Suwon; Hwaseong-Si Gyeonggi-do 445-743 Korea
| | - Jooyoung Lee
- Center for in Silico Protein Science, Korea Institute for Advanced Study; Seoul 130-722 Korea
- Center for Advanced Computation, Korea Institute for Advanced Study; Seoul 130-722 Korea
- School of Computational Sciences, Korea Institute for Advanced Study; Seoul 130-722 Korea
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21
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Putnam DK, Weiner BE, Woetzel N, Lowe EW, Meiler J. BCL::SAXS: GPU accelerated Debye method for computation of small angle X-ray scattering profiles. Proteins 2015; 83:1500-12. [PMID: 26018949 PMCID: PMC4797635 DOI: 10.1002/prot.24838] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/08/2015] [Accepted: 05/19/2015] [Indexed: 12/25/2022]
Abstract
Small angle X-ray scattering (SAXS) is an experimental technique used for structural characterization of macromolecules in solution. Here, we introduce BCL::SAXS--an algorithm designed to replicate SAXS profiles from rigid protein models at different levels of detail. We first show our derivation of BCL::SAXS and compare our results with the experimental scattering profile of hen egg white lysozyme. Using this protein we show how to generate SAXS profiles representing: (1) complete models, (2) models with approximated side chain coordinates, and (3) models with approximated side chain and loop region coordinates. We evaluated the ability of SAXS profiles to identify a correct protein topology from a non-redundant benchmark set of proteins. We find that complete SAXS profiles can be used to identify the correct protein by receiver operating characteristic (ROC) analysis with an area under the curve (AUC) > 99%. We show how our approximation of loop coordinates between secondary structure elements improves protein recognition by SAχS for protein models without loop regions and side chains. Agreement with SAXS data is a necessary but not sufficient condition for structure determination. We conclude that experimental SAXS data can be used as a filter to exclude protein models with large structural differences from the native.
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Affiliation(s)
- Daniel K. Putnam
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN 37235, USA
| | - Brian E. Weiner
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Nils Woetzel
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Edward W. Lowe
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN 37235, USA
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
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22
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Yang S. Methods for SAXS-based structure determination of biomolecular complexes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:7902-10. [PMID: 24888261 PMCID: PMC4285438 DOI: 10.1002/adma.201304475] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 03/10/2014] [Indexed: 05/20/2023]
Abstract
Measurements from small-angle X-ray scattering (SAXS) are highly informative to determine the structures of bimolecular complexes in solution. Here, current and recent SAXS-driven developments are described, with an emphasis on computational modeling. In particular, accurate methods to computing one theoretical scattering profile from a given structure model are discussed, with a key focus on structure factor coarse-graining and hydration contribution. Methods for reconstructing topological structures from an experimental SAXS profile are currently under active development. We report on several modeling tools designed for conformation generation that make use of either atomic-level or coarse-grained representations. Furthermore, since large, flexible biomolecules can adopt multiple well-defined conformations, a traditional single-conformation SAXS analysis is inappropriate, so we also discuss recent methods that utilize the concept of ensemble optimization, weighing in on the SAXS contributions of a heterogeneous mixture of conformations. These tools will ultimately posit the usefulness of SAXS data beyond a simple space-filling approach by providing a reliable structure characterization of biomolecular complexes under physiological conditions.
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Affiliation(s)
- Sichun Yang
- Center for Proteomics and Department of Pharmacology, Department of Physiology and Biophysics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106-4988, USA
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23
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Soares JSM, Gentile A, Scorsato V, Lima ADC, Kiyota E, Dos Santos ML, Piattoni CV, Huber SC, Aparicio R, Menossi M. Oligomerization, membrane association, and in vivo phosphorylation of sugarcane UDP-glucose pyrophosphorylase. J Biol Chem 2014; 289:33364-77. [PMID: 25320091 DOI: 10.1074/jbc.m114.590125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Sugarcane is a monocot plant that accumulates sucrose to levels of up to 50% of dry weight in the stalk. The mechanisms that are involved in sucrose accumulation in sugarcane are not well understood, and little is known with regard to factors that control the extent of sucrose storage in the stalks. UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9) is an enzyme that produces UDP-glucose, a key precursor for sucrose metabolism and cell wall biosynthesis. The objective of this work was to gain insights into the ScUGPase-1 expression pattern and regulatory mechanisms that control protein activity. ScUGPase-1 expression was negatively correlated with the sucrose content in the internodes during development, and only slight differences in the expression patterns were observed between two cultivars that differ in sucrose content. The intracellular localization of ScUGPase-1 indicated partial membrane association of this soluble protein in both the leaves and internodes. Using a phospho-specific antibody, we observed that ScUGPase-1 was phosphorylated in vivo at the Ser-419 site in the soluble and membrane fractions from the leaves but not from the internodes. The purified recombinant enzyme was kinetically characterized in the direction of UDP-glucose formation, and the enzyme activity was affected by redox modification. Preincubation with H2O2 strongly inhibited this activity, which could be reversed by DTT. Small angle x-ray scattering analysis indicated that the dimer interface is located at the C terminus and provided the first structural model of the dimer of sugarcane UGPase in solution.
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Affiliation(s)
- Jose Sergio M Soares
- From the Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Rua Monteiro Lobato, 255, C.P. 6109, Campinas, SP, Brazil
| | - Agustina Gentile
- From the Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Rua Monteiro Lobato, 255, C.P. 6109, Campinas, SP, Brazil
| | - Valeria Scorsato
- the Laboratório de Biologia Estrutural e Cristalografia, Instituto de Química, Universidade Estadual de Campinas, C.P. 6154, Campinas, SP, Brazil
| | - Aline da C Lima
- the Laboratório de Biologia Estrutural e Cristalografia, Instituto de Química, Universidade Estadual de Campinas, C.P. 6154, Campinas, SP, Brazil
| | - Eduardo Kiyota
- the Laboratório de Biologia Estrutural e Cristalografia, Instituto de Química, Universidade Estadual de Campinas, C.P. 6154, Campinas, SP, Brazil
| | - Marcelo Leite Dos Santos
- the Centro de Ciências Exatas e Tecnologia, Núcleo de Química, Universidade Federal do Sergipe, C.P. 49500000, Itabaiana, SE, Brazil
| | - Claudia V Piattoni
- the Instituto de Agrobiotecnologia del Litoral (UNL-CONICET), Universidad Nacional del Litoral, Ciudad Universitaria-Paraje El Pozo, CC242, S3000ZAA Santa Fe, Argentina
| | - Steven C Huber
- the Department of Agriculture Agricultural Research Service, and Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Ricardo Aparicio
- the Laboratório de Biologia Estrutural e Cristalografia, Instituto de Química, Universidade Estadual de Campinas, C.P. 6154, Campinas, SP, Brazil
| | - Marcelo Menossi
- From the Departamento de Genética, Evolução e Bioagentes, Instituto de Biologia, Universidade Estadual de Campinas, Rua Monteiro Lobato, 255, C.P. 6109, Campinas, SP, Brazil,
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24
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Schneidman-Duhovny D, Hammel M, Tainer JA, Sali A. Accurate SAXS profile computation and its assessment by contrast variation experiments. Biophys J 2014; 105:962-74. [PMID: 23972848 DOI: 10.1016/j.bpj.2013.07.020] [Citation(s) in RCA: 406] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 07/03/2013] [Accepted: 07/11/2013] [Indexed: 12/29/2022] Open
Abstract
A major challenge in structural biology is to characterize structures of proteins and their assemblies in solution. At low resolution, such a characterization may be achieved by small angle x-ray scattering (SAXS). Because SAXS analyses often require comparing profiles calculated from many atomic models against those determined by experiment, rapid and accurate profile computation from molecular structures is needed. We developed fast open-source x-ray scattering (FoXS) for profile computation. To match the experimental profile within the experimental noise, FoXS explicitly computes all interatomic distances and implicitly models the first hydration layer of the molecule. For assessing the accuracy of the modeled hydration layer, we performed contrast variation experiments for glucose isomerase and lysozyme, and found that FoXS can accurately represent density changes of this layer. The hydration layer model was also compared with a SAXS profile calculated for the explicit water molecules in the high-resolution structures of glucose isomerase and lysozyme. We tested FoXS on eleven protein, one DNA, and two RNA structures, revealing superior accuracy and speed versus CRYSOL, AquaSAXS, the Zernike polynomials-based method, and Fast-SAXS-pro. In addition, we demonstrated a significant correlation of the SAXS score with the accuracy of a structural model. Moreover, FoXS utility for analyzing heterogeneous samples was demonstrated for intrinsically flexible XLF-XRCC4 filaments and Ligase III-DNA complex. FoXS is extensively used as a standalone web server as a component of integrative structure determination by programs IMP, Chimera, and BILBOMD, as well as in other applications that require rapidly and accurately calculated SAXS profiles.
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Affiliation(s)
- Dina Schneidman-Duhovny
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA.
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25
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Putnam DK, Lowe EW, Meiler J. Reconstruction of SAXS Profiles from Protein Structures. Comput Struct Biotechnol J 2013; 8:e201308006. [PMID: 24688746 PMCID: PMC3962079 DOI: 10.5936/csbj.201308006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 11/12/2013] [Accepted: 11/22/2013] [Indexed: 11/30/2022] Open
Abstract
Small angle X-ray scattering (SAXS) is used for low resolution structural characterization of proteins often in combination with other experimental techniques. After briefly reviewing the theory of SAXS we discuss computational methods based on 1) the Debye equation and 2) Spherical Harmonics to compute intensity profiles from a particular macromolecular structure. Further, we review how these formulas are parameterized for solvent density and hydration shell adjustment. Finally we introduce our solution to compute SAXS profiles utilizing GPU acceleration.
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Affiliation(s)
- Daniel K Putnam
- Center for Structural Biology ; Department of Biomedical Informatics
| | - Edward W Lowe
- Center for Structural Biology ; Department of Chemistry, Vanderbilt University, Nashville, TN 37212, USA
| | - Jens Meiler
- Center for Structural Biology ; Department of Biomedical Informatics ; Department of Chemistry, Vanderbilt University, Nashville, TN 37212, USA
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26
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Rambo RP, Tainer JA. Super-resolution in solution X-ray scattering and its applications to structural systems biology. Annu Rev Biophys 2013; 42:415-41. [PMID: 23495971 DOI: 10.1146/annurev-biophys-083012-130301] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Small-angle X-ray scattering (SAXS) is a robust technique for the comprehensive structural characterizations of biological macromolecular complexes in solution. Here, we present a coherent synthesis of SAXS theory and experiment with a focus on analytical tools for accurate, objective, and high-throughput investigations. Perceived SAXS limitations are considered in light of its origins, and we present current methods that extend SAXS data analysis to the super-resolution regime. In particular, we discuss hybrid structural methods, illustrating the role of SAXS in structure refinement with NMR and ensemble refinement with single-molecule FRET. High-throughput genomics and proteomics are far outpacing macromolecular structure determinations, creating information gaps between the plethora of newly identified genes, known structures, and the structure-function relationship in the underlying biological networks. SAXS can bridge these information gaps by providing a reliable, high-throughput structural characterization of macromolecular complexes under physiological conditions.
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Affiliation(s)
- Robert P Rambo
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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27
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Schneidman-Duhovny D, Kim SJ, Sali A. Integrative structural modeling with small angle X-ray scattering profiles. BMC STRUCTURAL BIOLOGY 2012; 12:17. [PMID: 22800408 PMCID: PMC3427135 DOI: 10.1186/1472-6807-12-17] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 07/16/2012] [Indexed: 01/24/2023]
Abstract
Recent technological advances enabled high-throughput collection of Small Angle X-ray Scattering (SAXS) profiles of biological macromolecules. Thus, computational methods for integrating SAXS profiles into structural modeling are needed more than ever. Here, we review specifically the use of SAXS profiles for the structural modeling of proteins, nucleic acids, and their complexes. First, the approaches for computing theoretical SAXS profiles from structures are presented. Second, computational methods for predicting protein structures, dynamics of proteins in solution, and assembly structures are covered. Third, we discuss the use of SAXS profiles in integrative structure modeling approaches that depend simultaneously on several data types.
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Affiliation(s)
- Dina Schneidman-Duhovny
- Department of Bioengineering and Therapeutic Sciences, University of California at San Francisco, San Francisco, USA.
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