1
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Shelley KL, Garman EF. Identifying and avoiding radiation damage in macromolecular crystallography. Acta Crystallogr D Struct Biol 2024; 80:314-327. [PMID: 38700059 PMCID: PMC11066884 DOI: 10.1107/s2059798324003243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/15/2024] [Indexed: 05/05/2024] Open
Abstract
Radiation damage remains one of the major impediments to accurate structure solution in macromolecular crystallography. The artefacts of radiation damage can manifest as structural changes that result in incorrect biological interpretations being drawn from a model, they can reduce the resolution to which data can be collected and they can even prevent structure solution entirely. In this article, we discuss how to identify and mitigate against the effects of radiation damage at each stage in the macromolecular crystal structure-solution pipeline.
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Affiliation(s)
- Kathryn L. Shelley
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford OX1 3QU, United Kingdom
- Department of Biochemistry, University of Washington, Seattle, Washington, USA
- Institute for Protein Design, University of Washington, Seattle, Washington, USA
| | - Elspeth F. Garman
- Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford OX1 3QU, United Kingdom
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2
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Palaniappan C, Rajendran S, Sekar K. Alternate conformations found in protein structures implies biological functions: A case study using cyclophilin A. Curr Res Struct Biol 2024; 7:100145. [PMID: 38690327 PMCID: PMC11059445 DOI: 10.1016/j.crstbi.2024.100145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 03/16/2024] [Accepted: 04/15/2024] [Indexed: 05/02/2024] Open
Abstract
Protein dynamics linked to numerous biomolecular functions, such as ligand binding, allosteric regulation, and catalysis, must be better understood at the atomic level. Reactive atoms of key residues drive a repertoire of biomolecular functions by flipping between alternate conformations or conformational substates, seldom found in protein structures. Probing such sparsely sampled alternate conformations would provide mechanistic insight into many biological functions. We are therefore interested in evaluating the instance of amino acids adopted alternate conformations, either in backbone or side-chain atoms or in both. Accordingly, over 70000 protein structures appear to contain alternate conformations only 'A' and 'B' for any atom, particularly the instance of amino acids that adopted alternate conformations are more for Arg, Cys, Met, and Ser than others. The resulting protein structure analysis depicts that amino acids with alternate conformations are mainly found in the helical and β-regions and are often seen in high-resolution X-ray crystal structures. Furthermore, a case study on human cyclophilin A (CypA) was performed to explain the pre-existing intrinsic dynamics of catalytically critical residues from the CypA and how such intrinsic dynamics perturbed upon Ser99Thr mutation using molecular dynamics simulations on the ns-μs timescale. Simulation results demonstrated that the Ser99Thr mutation had impaired the alternate conformations or the catalytically productive micro-environment of Phe113, mimicking the experimentally observed perturbation captured by X-ray crystallography. In brief, a deeper comprehension of alternate conformations adopted by the amino acids may shed light on the interplay between protein structure, dynamics, and function.
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Affiliation(s)
- Chandrasekaran Palaniappan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, 560012, India
| | - Santhosh Rajendran
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore, 560012, India
| | - Kanagaraj Sekar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, 560012, India
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3
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Stachowski TR, Fischer M. FLEXR GUI: a graphical user interface for multi-conformer modeling of proteins. J Appl Crystallogr 2024; 57:580-586. [PMID: 38596743 PMCID: PMC11001397 DOI: 10.1107/s1600576724001523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 02/14/2024] [Indexed: 04/11/2024] Open
Abstract
Proteins are well known 'shapeshifters' which change conformation to function. In crystallography, multiple conformational states are often present within the crystal and the resulting electron-density map. Yet, explicitly incorporating alternative states into models to disentangle multi-conformer ensembles is challenging. We previously reported the tool FLEXR, which, within a few minutes, automatically separates conformational signal from noise and builds the corresponding, often missing, structural features into a multi-conformer model. To make the method widely accessible for routine multi-conformer building as part of the computational toolkit for macromolecular crystallography, we present a graphical user interface (GUI) for FLEXR, designed as a plugin for Coot 1. The GUI implementation seamlessly connects FLEXR models with the existing suite of validation and modeling tools available in Coot. We envision that FLEXR will aid crystallographers by increasing access to a multi-conformer modeling method that will ultimately lead to a better representation of protein conformational heterogeneity in the Protein Data Bank. In turn, deeper insights into the protein conformational landscape may inform biology or provide new opportunities for ligand design. The code is open source and freely available on GitHub at https://github.com/TheFischerLab/FLEXR-GUI.
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Affiliation(s)
- Timothy R. Stachowski
- Department of Chemical Biology and Therapeutics, St Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Marcus Fischer
- Department of Chemical Biology and Therapeutics, St Jude Children’s Research Hospital, Memphis, TN 38105, USA
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4
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Díaz RE, Ecker AK, Correy GJ, Asthana P, Young ID, Faust B, Thompson MC, Seiple IB, Van Dyken SJ, Locksley RM, Fraser JS. Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase. bioRxiv 2024:2023.06.03.542675. [PMID: 37398339 PMCID: PMC10312649 DOI: 10.1101/2023.06.03.542675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high resolution crystal structures of mAMCase in complex with oligomeric GlcNAcn, the building block of chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.
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Affiliation(s)
- Roberto Efraín Díaz
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew K Ecker
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
- Chemistry and Chemical Biology Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Galen J Correy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Pooja Asthana
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Iris D Young
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bryan Faust
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Biophysics Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Michael C Thompson
- Department of Chemistry and Chemical Biology, University of California, Merced, Merced, CA 95343, USA
| | - Ian B Seiple
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Steven J Van Dyken
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Richard M Locksley
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
- University of California, San Francisco, Howard Hughes Medical Institute, San Francisco, CA 94143, USA
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
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5
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Guerrero L, Ebrahim A, Riley BT, Kim M, Huang Q, Finke AD, Keedy DA. Pushed to extremes: distinct effects of high temperature versus pressure on the structure of STEP. Commun Biol 2024; 7:59. [PMID: 38216663 PMCID: PMC10786866 DOI: 10.1038/s42003-023-05609-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/20/2023] [Indexed: 01/14/2024] Open
Abstract
Protein function hinges on small shifts of three-dimensional structure. Elevating temperature or pressure may provide experimentally accessible insights into such shifts, but the effects of these distinct perturbations on protein structures have not been compared in atomic detail. To quantitatively explore these two axes, we report the first pair of structures at physiological temperature versus. high pressure for the same protein, STEP (PTPN5). We show that these perturbations have distinct and surprising effects on protein volume, patterns of ordered solvent, and local backbone and side-chain conformations. This includes interactions between key catalytic loops only at physiological temperature, and a distinct conformational ensemble for another active-site loop only at high pressure. Strikingly, in torsional space, physiological temperature shifts STEP toward previously reported active-like states, while high pressure shifts it toward a previously uncharted region. Altogether, our work indicates that temperature and pressure are complementary, powerful, fundamental macromolecular perturbations.
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Affiliation(s)
- Liliana Guerrero
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, 10031, USA
- PhD Program in Biochemistry, CUNY Graduate Center, New York, NY, 10016, USA
| | - Ali Ebrahim
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, 10031, USA
| | - Blake T Riley
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, 10031, USA
| | - Minyoung Kim
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, 10031, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - Qingqiu Huang
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY, 14853, USA
| | - Aaron D Finke
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY, 14853, USA
| | - Daniel A Keedy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, 10031, USA.
- Department of Chemistry and Biochemistry, City College of New York, New York, NY, 10031, USA.
- PhD Programs in Biochemistry, Biology, & Chemistry, CUNY Graduate Center, New York, NY, 10016, USA.
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6
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Platzer G, Ptaszek AL, Böttcher J, Fuchs JE, Geist L, Braun D, McConnell DB, Konrat R, Sánchez-Murcia PA, Mayer M. Ligand 1 H NMR Chemical Shifts as Accurate Reporters for Protein-Ligand Binding Interfaces in Solution. Chemphyschem 2024; 25:e202300636. [PMID: 37955910 DOI: 10.1002/cphc.202300636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/23/2023] [Indexed: 11/14/2023]
Abstract
The availability of high-resolution 3D structural information is crucial for investigating guest-host systems across a wide range of fields. In the context of drug discovery, the information is routinely used to establish and validate structure-activity relationships, grow initial hits from screening campaigns, and to guide molecular docking. For the generation of protein-ligand complex structural information, X-ray crystallography is the experimental method of choice, however, with limited information on protein flexibility. An experimentally verified structural model of the binding interface in the native solution-state would support medicinal chemists in their molecular design decisions. Here we demonstrate that protein-bound ligand 1 H NMR chemical shifts are highly sensitive and accurate probes for the immediate chemical environment of protein-ligand interfaces. By comparing the experimental ligand 1 H chemical shift values with those computed from the X-ray structure using quantum mechanics methodology, we identify significant disagreements for parts of the ligand between the two experimental techniques. We show that quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) ensembles can be used to refine initial X-ray co-crystal structures resulting in a better agreement with experimental 1 H ligand chemical shift values. Overall, our findings highlight the usefulness of ligand 1 H NMR chemical shift information in combination with a QM/MM MD workflow for generating protein-ligand ensembles that accurately reproduce solution structural data.
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Affiliation(s)
- Gerald Platzer
- Christian Doppler Laboratory for High-Content Structural Biology and Biotechnology, Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, 1030-, Vienna, Austria
- MAG-LAB GmbH, Karl-Farkas-Gasse 22, 1030-, Vienna, Austria
| | - Aleksandra L Ptaszek
- Christian Doppler Laboratory for High-Content Structural Biology and Biotechnology, Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, 1030-, Vienna, Austria
- Laboratory for Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto Loewi Research Center, Medical University Graz, Neue Stiftingtalstrasse 6/III, 8010-, Graz, Austria
| | - Jark Böttcher
- Boehringer Ingelheim RCV GmbH & Co. KG, Dr. Boehringer Gasse 5-11, 1121-, Vienna, Austria
| | - Julian E Fuchs
- Boehringer Ingelheim RCV GmbH & Co. KG, Dr. Boehringer Gasse 5-11, 1121-, Vienna, Austria
| | - Leonhard Geist
- Boehringer Ingelheim RCV GmbH & Co. KG, Dr. Boehringer Gasse 5-11, 1121-, Vienna, Austria
| | - Daniel Braun
- Christian Doppler Laboratory for High-Content Structural Biology and Biotechnology, Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, 1030-, Vienna, Austria
| | - Darryl B McConnell
- Boehringer Ingelheim RCV GmbH & Co. KG, Dr. Boehringer Gasse 5-11, 1121-, Vienna, Austria
| | - Robert Konrat
- Christian Doppler Laboratory for High-Content Structural Biology and Biotechnology, Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Campus Vienna Biocenter 5, 1030-, Vienna, Austria
| | - Pedro A Sánchez-Murcia
- Laboratory for Computer-Aided Molecular Design, Division of Medicinal Chemistry, Otto Loewi Research Center, Medical University Graz, Neue Stiftingtalstrasse 6/III, 8010-, Graz, Austria
| | - Moriz Mayer
- Boehringer Ingelheim RCV GmbH & Co. KG, Dr. Boehringer Gasse 5-11, 1121-, Vienna, Austria
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7
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Sharma S, Skaist Mehlman T, Sagabala RS, Boivin B, Keedy DA. High-resolution double vision of the allosteric phosphatase PTP1B. Acta Crystallogr F Struct Biol Commun 2024; 80:1-12. [PMID: 38133579 PMCID: PMC10833341 DOI: 10.1107/s2053230x23010749] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) plays important roles in cellular homeostasis and is a highly validated therapeutic target for multiple human ailments, including diabetes, obesity and breast cancer. However, much remains to be learned about how conformational changes may convey information through the structure of PTP1B to enable allosteric regulation by ligands or functional responses to mutations. High-resolution X-ray crystallography can offer unique windows into protein conformational ensembles, but comparison of even high-resolution structures is often complicated by differences between data sets, including non-isomorphism. Here, the highest resolution crystal structure of apo wild-type (WT) PTP1B to date is presented out of a total of ∼350 PTP1B structures in the PDB. This structure is in a crystal form that is rare for PTP1B, with two unique copies of the protein that exhibit distinct patterns of conformational heterogeneity, allowing a controlled comparison of local disorder across the two chains within the same asymmetric unit. The conformational differences between these chains are interrogated in the apo structure and between several recently reported high-resolution ligand-bound structures. Electron-density maps in a high-resolution structure of a recently reported activating double mutant are also examined, and unmodeled alternate conformations in the mutant structure are discovered that coincide with regions of enhanced conformational heterogeneity in the new WT structure. These results validate the notion that these mutations operate by enhancing local dynamics, and suggest a latent susceptibility to such changes in the WT enzyme. Together, these new data and analysis provide a detailed view of the conformational ensemble of PTP1B and highlight the utility of high-resolution crystallography for elucidating conformational heterogeneity with potential relevance for function.
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Affiliation(s)
- Shivani Sharma
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA
- PhD Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Tamar Skaist Mehlman
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA
| | - Reddy Sudheer Sagabala
- Department of Nanobioscience, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Benoit Boivin
- Department of Nanobioscience, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Daniel A. Keedy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA
- PhD Programs in Biochemistry, Biology and Chemistry, CUNY Graduate Center, New York, NY 10016, USA
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8
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Thompson MC. Combining temperature perturbations with X-ray crystallography to study dynamic macromolecules: A thorough discussion of experimental methods. Methods Enzymol 2023; 688:255-305. [PMID: 37748829 DOI: 10.1016/bs.mie.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Temperature is an important state variable that governs the behavior of microscopic systems, yet crystallographers rarely exploit temperature changes to study the structure and dynamics of biological macromolecules. In fact, approximately 90% of crystal structures in the Protein Data Bank were determined under cryogenic conditions, because sample cryocooling makes crystals robust to X-ray radiation damage and facilitates data collection. On the other hand, cryocooling can introduce artifacts into macromolecular structures, and can suppress conformational dynamics that are critical for function. Fortunately, recent advances in X-ray detector technology, X-ray sources, and computational data processing algorithms make non-cryogenic X-ray crystallography easier and more broadly applicable than ever before. Without the reliance on cryocooling, high-resolution crystallography can be combined with various temperature perturbations to gain deep insight into the conformational landscapes of macromolecules. This Chapter reviews the historical reasons for the prevalence of cryocooling in macromolecular crystallography, and discusses its potential drawbacks. Next, the Chapter summarizes technological developments and methodologies that facilitate non-cryogenic crystallography experiments. Finally, the chapter discusses the theoretical underpinnings and practical aspects of multi-temperature and temperature-jump crystallography experiments, which are powerful tools for understanding the relationship between the structure, dynamics, and function of proteins and other biological macromolecules.
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Affiliation(s)
- Michael C Thompson
- Department of Chemistry and Biochemistry, University of California, Merced, Merced, CA, United States.
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9
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Case DA. MD simulations of macromolecular crystals: Implications for the analysis of Bragg and diffuse scattering. Methods Enzymol 2023; 688:145-168. [PMID: 37748825 DOI: 10.1016/bs.mie.2023.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Some of our most detailed information about structure and dynamics of macromolecules comes from X-ray-diffraction studies in crystalline environments. More than 170,000 atomic models have been deposited in the Protein Data Bank, and the number of observations (typically of intensities of Bragg diffraction peaks) is generally quite large, when compared to other experimental methods. Nevertheless, the general agreement between calculated and observed intensities is far outside the experimental precision, and the majority of scattered photons fall between the sharp Bragg peaks, and are rarely taken into account. This chapter considers how molecular dynamics simulations can be used to explore the connections between microscopic behavior in a crystalline lattice and observed scattering intensities, and point the way to new atomic models that could more faithfully recapitulate Bragg intensities and extract useful information from the diffuse scattering that lies between those peaks.
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Affiliation(s)
- David A Case
- Dept. of Chemistry & Chemical Biology, Rutgers University, Piscataway, NJ, United States.
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10
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Peck A, Lane TJ, Poitevin F. Modeling diffuse scattering with simple, physically interpretable models. Methods Enzymol 2023; 688:169-194. [PMID: 37748826 DOI: 10.1016/bs.mie.2023.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Diffuse scattering has long been proposed to probe protein dynamics relevant for biological function, and more recently, as a tool to aid structure determination. Despite recent advances in measuring and modeling this signal, the field has not been able to routinely use experimental diffuse scattering for either application. A persistent challenge has been to devise models that are sophisticated enough to robustly reproduce experimental diffuse features but remain readily interpretable from the standpoint of structural biology. This chapter presents eryx, a suite of computational tools to evaluate the primary models of disorder that have been used to analyze protein diffuse scattering. By facilitating comparative modeling, eryx aims to provide insights into the physical origins of this signal and help identify the sources of disorder that are critical for reproducing experimental features. This framework also lays the groundwork for the development of more advanced models that integrate different types of disorder without loss of interpretability.
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Affiliation(s)
- Ariana Peck
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, United States.
| | | | - Frédéric Poitevin
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, United States
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11
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Du S, Wankowicz SA, Yabukarski F, Doukov T, Herschlag D, Fraser JS. Refinement of multiconformer ensemble models from multi-temperature X-ray diffraction data. Methods Enzymol 2023; 688:223-254. [PMID: 37748828 PMCID: PMC10637719 DOI: 10.1016/bs.mie.2023.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Conformational ensembles underlie all protein functions. Thus, acquiring atomic-level ensemble models that accurately represent conformational heterogeneity is vital to deepen our understanding of how proteins work. Modeling ensemble information from X-ray diffraction data has been challenging, as traditional cryo-crystallography restricts conformational variability while minimizing radiation damage. Recent advances have enabled the collection of high quality diffraction data at ambient temperatures, revealing innate conformational heterogeneity and temperature-driven changes. Here, we used diffraction datasets for Proteinase K collected at temperatures ranging from 313 to 363 K to provide a tutorial for the refinement of multiconformer ensemble models. Integrating automated sampling and refinement tools with manual adjustments, we obtained multiconformer models that describe alternative backbone and sidechain conformations, their relative occupancies, and interconnections between conformers. Our models revealed extensive and diverse conformational changes across temperature, including increased bound peptide ligand occupancies, different Ca2+ binding site configurations and altered rotameric distributions. These insights emphasize the value and need for multiconformer model refinement to extract ensemble information from diffraction data and to understand ensemble-function relationships.
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Affiliation(s)
- Siyuan Du
- Department of Biochemistry, Stanford University, Stanford, CA, United States; Department of Chemistry, Stanford University, Stanford, CA, United States
| | - Stephanie A Wankowicz
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, United States
| | - Filip Yabukarski
- Department of Biochemistry, Stanford University, Stanford, CA, United States; Bristol-Myers Squibb, San Diego, CA, United States
| | - Tzanko Doukov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, United States
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA, United States; Department of Chemical Engineering, Stanford University, Stanford, CA, United States; Stanford ChEM-H, Stanford University, Stanford, CA, United States
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, United States; Quantitative Biosciences Institute, University of California, San Francisco, CA, United States.
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12
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Du S, Wankowicz SA, Yabukarski F, Doukov T, Herschlag D, Fraser JS. Refinement of Multiconformer Ensemble Models from Multi-temperature X-ray Diffraction Data. bioRxiv 2023:2023.05.05.539620. [PMID: 37205593 PMCID: PMC10187334 DOI: 10.1101/2023.05.05.539620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Conformational ensembles underlie all protein functions. Thus, acquiring atomic-level ensemble models that accurately represent conformational heterogeneity is vital to deepen our understanding of how proteins work. Modeling ensemble information from X-ray diffraction data has been challenging, as traditional cryo-crystallography restricts conformational variability while minimizing radiation damage. Recent advances have enabled the collection of high quality diffraction data at ambient temperatures, revealing innate conformational heterogeneity and temperature-driven changes. Here, we used diffraction datasets for Proteinase K collected at temperatures ranging from 313 to 363K to provide a tutorial for the refinement of multiconformer ensemble models. Integrating automated sampling and refinement tools with manual adjustments, we obtained multiconformer models that describe alternative backbone and sidechain conformations, their relative occupancies, and interconnections between conformers. Our models revealed extensive and diverse conformational changes across temperature, including increased bound peptide ligand occupancies, different Ca2+ binding site configurations and altered rotameric distributions. These insights emphasize the value and need for multiconformer model refinement to extract ensemble information from diffraction data and to understand ensemble-function relationships.
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Affiliation(s)
- Siyuan Du
- Department of Biochemistry, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Stephanie A. Wankowicz
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California 94143, United States
| | - Filip Yabukarski
- Department of Biochemistry, Stanford University, Stanford, California 94305, United States
- Bristol-Myers Squibb, San Diego, California 92121, United States
| | - Tzanko Doukov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, California 94305, United States
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - James S. Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California 94143, United States
- Quantitative Biosciences Institute, University of California, San Francisco, California 94143, United States
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13
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Guerrero L, Ebrahim A, Riley BT, Kim M, Huang Q, Finke AD, Keedy DA. Pushed to extremes: distinct effects of high temperature vs. pressure on the structure of an atypical phosphatase. bioRxiv 2023:2023.05.02.538097. [PMID: 37205580 PMCID: PMC10187168 DOI: 10.1101/2023.05.02.538097] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Protein function hinges on small shifts of three-dimensional structure. Elevating temperature or pressure may provide experimentally accessible insights into such shifts, but the effects of these distinct perturbations on protein structures have not been compared in atomic detail. To quantitatively explore these two axes, we report the first pair of structures at physiological temperature vs. high pressure for the same protein, STEP (PTPN5). We show that these perturbations have distinct and surprising effects on protein volume, patterns of ordered solvent, and local backbone and side-chain conformations. This includes novel interactions between key catalytic loops only at physiological temperature, and a distinct conformational ensemble for another active-site loop only at high pressure. Strikingly, in torsional space, physiological temperature shifts STEP toward previously reported active-like states, while high pressure shifts it toward a previously uncharted region. Together, our work argues that temperature and pressure are complementary, powerful, fundamental macromolecular perturbations.
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Affiliation(s)
- Liliana Guerrero
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031
- PhD Program in Biochemistry, CUNY Graduate Center, New York, NY 10016
| | - Ali Ebrahim
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031
| | - Blake T Riley
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031
| | - Minyoung Kim
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Qingqiu Huang
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853
| | - Aaron D Finke
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853
| | - Daniel A Keedy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031
- Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031
- PhD Programs in Biochemistry, Biology, & Chemistry, CUNY Graduate Center, New York, NY 10016
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14
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Abstract
In many molecular modeling applications, the standard procedure is still to handle proteins as single, rigid structures. While the importance of conformational flexibility is widely known, handling it remains challenging. Even the crystal structure of a protein usually contains variability exemplified in alternate side chain orientations or backbone segments. This conformational variability is encoded in PDB structure files by so-called alternate locations (AltLocs). Most modeling approaches either ignore AltLocs or resolve them with simple heuristics early on during structure import. We analyzed the occurrence and usage of AltLocs in the PDB and developed an algorithm to automatically handle AltLocs in PDB files enabling all structure-based methods using rigid structures to take the alternative protein conformations described by AltLocs into consideration. A respective software tool named AltLocEnumerator can be used as a structure preprocessor to easily exploit AltLocs. While the amount of data makes it difficult to show impact on a statistical level, handling AltLocs has a substantial impact on a case-by-case basis. We believe that the inspection and consideration of AltLocs is a very valuable approach in many modeling scenarios.
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Affiliation(s)
- Torben Gutermuth
- Universität Hamburg, ZBH - Center for Bioinformatics, Bundesstraße 43, 20146 Hamburg, Germany
| | - Jochen Sieg
- Universität Hamburg, ZBH - Center for Bioinformatics, Bundesstraße 43, 20146 Hamburg, Germany
| | - Tim Stohn
- Universität Hamburg, ZBH - Center for Bioinformatics, Bundesstraße 43, 20146 Hamburg, Germany
| | - Matthias Rarey
- Universität Hamburg, ZBH - Center for Bioinformatics, Bundesstraße 43, 20146 Hamburg, Germany
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15
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Doukov T, Herschlag D, Yabukarski F. Obtaining anomalous and ensemble information from protein crystals from 220 K up to physiological temperatures. Acta Crystallogr D Struct Biol 2023; 79:212-223. [PMID: 36876431 PMCID: PMC9986799 DOI: 10.1107/s205979832300089x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/31/2023] [Indexed: 03/01/2023] Open
Abstract
X-ray crystallography has been invaluable in delivering structural information about proteins. Previously, an approach has been developed that allows high-quality X-ray diffraction data to be obtained from protein crystals at and above room temperature. Here, this previous work is built on and extended by showing that high-quality anomalous signal can be obtained from single protein crystals using diffraction data collected at 220 K up to physiological temperatures. The anomalous signal can be used to directly determine the structure of a protein, i.e. to phase the data, as is routinely performed under cryoconditions. This ability is demonstrated by obtaining diffraction data from model lysozyme, thaumatin and proteinase K crystals, the anomalous signal from which allowed their structures to be solved experimentally at 7.1 keV X-ray energy and at room temperature with relatively low data redundancy. It is also demonstrated that the anomalous signal from diffraction data obtained at 310 K (37°C) can be used to solve the structure of proteinase K and to identify ordered ions. The method provides useful anomalous signal at temperatures down to 220 K, resulting in an extended crystal lifetime and increased data redundancy. Finally, we show that useful anomalous signal can be obtained at room temperature using X-rays of 12 keV energy as typically used for routine data collection, allowing this type of experiment to be carried out at widely accessible synchrotron beamline energies and enabling the simultaneous extraction of high-resolution data and anomalous signal. With the recent emphasis on obtaining conformational ensemble information for proteins, the high resolution of the data allows such ensembles to be built, while the anomalous signal allows the structure to be experimentally solved, ions to be identified, and water molecules and ions to be differentiated. Because bound metal-, phosphorus- and sulfur-containing ions all have anomalous signal, obtaining anomalous signal across temperatures and up to physiological temperatures will provide a more complete description of protein conformational ensembles, function and energetics.
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Affiliation(s)
- Tzanko Doukov
- SMB, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Daniel Herschlag
- Deparment of Biochemistry, Stanford University, Stanford, CA 94305, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
- Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Filip Yabukarski
- Deparment of Biochemistry, Stanford University, Stanford, CA 94305, USA
- Bristol-Myers Squibb, San Diego, CA 92121, USA
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16
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Sharma S, Ebrahim A, Keedy DA. Room-temperature serial synchrotron crystallography of the human phosphatase PTP1B. Acta Crystallogr F Struct Biol Commun 2023; 79:23-30. [PMID: 36598353 PMCID: PMC9813971 DOI: 10.1107/s2053230x22011645] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 12/04/2022] [Indexed: 12/24/2022] Open
Abstract
Room-temperature X-ray crystallography provides unique insights into protein conformational heterogeneity, but obtaining sufficiently large protein crystals is a common hurdle. Serial synchrotron crystallography (SSX) helps to address this hurdle by allowing the use of many medium- to small-sized crystals. Here, a recently introduced serial sample-support chip system has been used to obtain the first SSX structure of a human phosphatase, specifically protein tyrosine phosphatase 1B (PTP1B) in the unliganded (apo) state. In previous apo room-temperature structures, the active site and allosteric sites adopted alternate conformations, including open and closed conformations of the active-site WPD loop and of a distal allosteric site. By contrast, in our SSX structure the active site is best fitted with a single conformation, but the distal allosteric site is best fitted with alternate conformations. This observation argues for additional nuance in interpreting the nature of allosteric coupling in this protein. Overall, our results illustrate the promise of serial methods for room-temperature crystallography, as well as future avant-garde crystallography experiments, for PTP1B and other proteins.
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Affiliation(s)
- Shivani Sharma
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA,PhD Program in Biology, CUNY Graduate Center, New York, NY 10016, USA
| | - Ali Ebrahim
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA
| | - Daniel A. Keedy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA,Department of Chemistry and Biochemistry, City College of New York, New York, NY 10031, USA,PhD Programs in Biochemistry, Biology and Chemistry, CUNY Graduate Center, New York, NY 10016, USA,Correspondence e-mail:
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17
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Thorne RE. Determining biomolecular structures near room temperature using X-ray crystallography: concepts, methods and future optimization. Acta Crystallogr D Struct Biol 2023; 79:78-94. [PMID: 36601809 PMCID: PMC9815097 DOI: 10.1107/s2059798322011652] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 12/04/2022] [Indexed: 01/05/2023] Open
Abstract
For roughly two decades, cryocrystallography has been the overwhelmingly dominant method for determining high-resolution biomolecular structures. Competition from single-particle cryo-electron microscopy and micro-electron diffraction, increased interest in functionally relevant information that may be missing or corrupted in structures determined at cryogenic temperature, and interest in time-resolved studies of the biomolecular response to chemical and optical stimuli have driven renewed interest in data collection at room temperature and, more generally, at temperatures from the protein-solvent glass transition near 200 K to ∼350 K. Fischer has recently reviewed practical methods for room-temperature data collection and analysis [Fischer (2021), Q. Rev. Biophys. 54, e1]. Here, the key advantages and physical principles of, and methods for, crystallographic data collection at noncryogenic temperatures and some factors relevant to interpreting the resulting data are discussed. For room-temperature data collection to realize its potential within the structural biology toolkit, streamlined and standardized methods for delivering crystals prepared in the home laboratory to the synchrotron and for automated handling and data collection, similar to those for cryocrystallography, should be implemented.
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Affiliation(s)
- Robert E. Thorne
- Physics Department, Cornell University, Ithaca, NY 14853, USA
- MiTeGen LLC, PO Box 3867, Ithaca, NY 14850, USA
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18
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Rhinehardt K, Dong M. Computational analysis of protein conformational heterogeneity. J Biomol Struct Dyn 2022; 40:12100-12105. [PMID: 34424141 DOI: 10.1080/07391102.2021.1967784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this paper, we applied the molecular dynamics (MD) simulations and used thermolysin as the system to study the overall protein dynamics and side chain dihedral angles across the Arrhenius break. Simulations were performed at a high temperature of 36 °C which is above the previously observed Arrhenius break, and the lower temperature of 20 °C which is below the Arrhenius break. We observed different protein dynamics and conformational heterogeneity of side chain dihedral angles of thermolysin at the two temperatures. Our results indicated that certain regions of thermolysin have a higher level of fluctuation at lower temperature. A temperature dependent dihedral angles were also observed at the two temperatures. The changes observed in the protein indicated key areas of temperature sensitivity within the protein.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kristen Rhinehardt
- Department of Computational Data Science and Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
| | - Ming Dong
- Department of Chemistry, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
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19
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Young BD, Cook ME, Costabile BK, Samanta R, Zhuang X, Sevdalis SE, Varney KM, Mancia F, Matysiak S, Lattman E, Weber DJ. Binding and Functional Folding (BFF): A Physiological Framework for Studying Biomolecular Interactions and Allostery. J Mol Biol 2022; 434:167872. [PMID: 36354074 PMCID: PMC10871162 DOI: 10.1016/j.jmb.2022.167872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/20/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
EF-hand Ca2+-binding proteins (CBPs), such as S100 proteins (S100s) and calmodulin (CaM), are signaling proteins that undergo conformational changes upon increasing intracellular Ca2+. Upon binding Ca2+, S100 proteins and CaM interact with protein targets and induce important biological responses. The Ca2+-binding affinity of CaM and most S100s in the absence of target is weak (CaKD > 1 μM). However, upon effector protein binding, the Ca2+ affinity of these proteins increases via heterotropic allostery (CaKD < 1 μM). Because of the high number and micromolar concentrations of EF-hand CBPs in a cell, at any given time, allostery is required physiologically, allowing for (i) proper Ca2+ homeostasis and (ii) strict maintenance of Ca2+-signaling within a narrow dynamic range of free Ca2+ ion concentrations, [Ca2+]free. In this review, mechanisms of allostery are coalesced into an empirical "binding and functional folding (BFF)" physiological framework. At the molecular level, folding (F), binding and folding (BF), and BFF events include all atoms in the biomolecular complex under study. The BFF framework is introduced with two straightforward BFF types for proteins (type 1, concerted; type 2, stepwise) and considers how homologous and nonhomologous amino acid residues of CBPs and their effector protein(s) evolved to provide allosteric tightening of Ca2+ and simultaneously determine how specific and relatively promiscuous CBP-target complexes form as both are needed for proper cellular function.
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Affiliation(s)
- Brianna D Young
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary E Cook
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brianna K Costabile
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Riya Samanta
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Xinhao Zhuang
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Spiridon E Sevdalis
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kristen M Varney
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Silvina Matysiak
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Eaton Lattman
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - David J Weber
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; The Institute of Bioscience and Biotechnology Research (IBBR), Rockville, MD 20850, USA.
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20
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Dicks L, Wales DJ. Exploiting Sequence-Dependent Rotamer Information in Global Optimization of Proteins. J Phys Chem B 2022; 126:8381-8390. [PMID: 36257022 PMCID: PMC9623586 DOI: 10.1021/acs.jpcb.2c04647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Rotamers, namely amino acid side chain conformations common to many different peptides, can be compiled into libraries. These rotamer libraries are used in protein modeling, where the limited conformational space occupied by amino acid side chains is exploited. Here, we construct a sequence-dependent rotamer library from simulations of all possible tripeptides, which provides rotameric states dependent on adjacent amino acids. We observe significant sensitivity of rotamer populations to sequence and find that the library is successful in locating side chain conformations present in crystal structures. The library is designed for applications with basin-hopping global optimization, where we use it to propose moves in conformational space. The addition of rotamer moves significantly increases the efficiency of protein structure prediction within this framework, and we determine parameters to optimize efficiency.
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Affiliation(s)
- L. Dicks
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom,IBM
Research, The Hartree Centre STFC Laboratory,
Sci-Tech Daresbury, Warrington WA4 4AD, United Kingdom
| | - D. J. Wales
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom,
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21
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein-Ligand Interfaces with Temperature. Angew Chem Int Ed Engl 2022; 61:e202112919. [PMID: 35648650 PMCID: PMC9329195 DOI: 10.1002/anie.202112919] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Indexed: 12/14/2022]
Abstract
High-resolution crystal structures highlight the importance of water networks in protein-ligand interactions. However, as these are typically determined at cryogenic temperature, resulting insights may be structurally precise but not biologically accurate. By collecting 10 matched room-temperature and cryogenic datasets of the biomedical target Hsp90α, we identified changes in water networks that impact protein conformations at the ligand binding interface. Water repositioning with temperature repopulates protein ensembles and ligand interactions. We introduce Flipper conformational barcodes to identify temperature-sensitive regions in electron density maps. This revealed that temperature-responsive states coincide with ligand-responsive regions and capture unique binding signatures that disappear upon cryo-cooling. Our results have implications for discovering Hsp90 selective ligands, and, more generally, for the utility of hidden protein and water conformations in drug discovery.
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Affiliation(s)
- Timothy R. Stachowski
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Murugendra Vanarotti
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Jayaraman Seetharaman
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Karlo Lopez
- School of Natural SciencesMathematicsand EngineeringCalifornia State UniversityBakersfieldCA 93311USA
| | - Marcus Fischer
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
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22
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Yabukarski F, Doukov T, Mokhtari DA, Du S, Herschlag D. Evaluating the impact of X-ray damage on conformational heterogeneity in room-temperature (277 K) and cryo-cooled protein crystals. Acta Crystallogr D Struct Biol 2022; 78:945-963. [PMID: 35916220 PMCID: PMC9344472 DOI: 10.1107/s2059798322005939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 06/02/2022] [Indexed: 11/10/2022] Open
Abstract
Cryo-cooling has been nearly universally adopted to mitigate X-ray damage and facilitate crystal handling in protein X-ray crystallography. However, cryo X-ray crystallographic data provide an incomplete window into the ensemble of conformations that is at the heart of protein function and energetics. Room-temperature (RT) X-ray crystallography provides accurate ensemble information, and recent developments allow conformational heterogeneity (the experimental manifestation of ensembles) to be extracted from single-crystal data. Nevertheless, high sensitivity to X-ray damage at RT raises concerns about data reliability. To systematically address this critical issue, increasingly X-ray-damaged high-resolution data sets (1.02–1.52 Å resolution) were obtained from single proteinase K, thaumatin and lysozyme crystals at RT (277 K). In each case a modest increase in conformational heterogeneity with X-ray damage was observed. Merging data with different extents of damage (as is typically carried out) had negligible effects on conformational heterogeneity until the overall diffraction intensity decayed to ∼70% of its initial value. These effects were compared with X-ray damage effects in cryo-cooled crystals by carrying out an analogous analysis of increasingly damaged proteinase K cryo data sets (0.9–1.16 Å resolution). X-ray damage-associated heterogeneity changes were found that were not observed at RT. This property renders it difficult to distinguish real from artefactual conformations and to determine the conformational response to changes in temperature. The ability to acquire reliable heterogeneity information from single crystals at RT, together with recent advances in RT data collection at accessible synchrotron beamlines, provides a strong motivation for the widespread adoption of RT X-ray crystallography to obtain conformational ensemble information.
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23
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De Zitter E, Coquelle N, Oeser P, Barends TRM, Colletier JP. Xtrapol8 enables automatic elucidation of low-occupancy intermediate-states in crystallographic studies. Commun Biol 2022; 5:640. [PMID: 35768542 PMCID: PMC9243118 DOI: 10.1038/s42003-022-03575-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 06/10/2022] [Indexed: 11/09/2022] Open
Abstract
Unstable states studied in kinetic, time-resolved and ligand-based crystallography are often characterized by a low occupancy, which hinders structure determination by conventional methods. To automatically extract structural information pertaining to these states, we developed Xtrapol8, a program which (i) applies various flavors of Bayesian-statistics weighting to generate the most informative Fourier difference maps; (ii) determines the occupancy of the intermediate states by use of methods hitherto not available; (iii) calculates extrapolated structure factors using the various proposed formalisms while handling the issue of negative structure factor amplitudes, and (iv) refines the corresponding structures in real and reciprocal-space. The use of Xtrapol8 could accelerate data processing in kinetic and time-resolved crystallographic studies, and as well foster the identification of drug-targetable states in ligand-based crystallography. The software Xtrapol8 extracts low occupancy states and can thereby accelerate and facilitate data processing in kinetic, timeresolved and ligand-based crystallographic studies.
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Affiliation(s)
- Elke De Zitter
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, 38000, Grenoble, France
| | - Nicolas Coquelle
- European Synchrotron Radiation Facility (ESRF), BP 220, 38043, Grenoble, France
| | - Paula Oeser
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, 38000, Grenoble, France
| | - Thomas R M Barends
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
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24
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein‐Ligand Interfaces With Temperature. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Timothy R Stachowski
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | - Murugendra Vanarotti
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | | | - Karlo Lopez
- California State University - Bakersfield School of Natural Sciences, Mathematics, and Engineering UNITED STATES
| | - Marcus Fischer
- St. Jude Children's Research Hospital Chemical Biology & Therapeutics 262 Danny Thomas Place 38105 Memphis UNITED STATES
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25
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Wankowicz SA, de Oliveira SH, Hogan DW, van den Bedem H, Fraser JS. Ligand binding remodels protein side-chain conformational heterogeneity. eLife 2022; 11:e74114. [PMID: 35312477 PMCID: PMC9084896 DOI: 10.7554/elife.74114] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 03/18/2022] [Indexed: 12/15/2022] Open
Abstract
While protein conformational heterogeneity plays an important role in many aspects of biological function, including ligand binding, its impact has been difficult to quantify. Macromolecular X-ray diffraction is commonly interpreted with a static structure, but it can provide information on both the anharmonic and harmonic contributions to conformational heterogeneity. Here, through multiconformer modeling of time- and space-averaged electron density, we measure conformational heterogeneity of 743 stringently matched pairs of crystallographic datasets that reflect unbound/apo and ligand-bound/holo states. When comparing the conformational heterogeneity of side chains, we observe that when binding site residues become more rigid upon ligand binding, distant residues tend to become more flexible, especially in non-solvent-exposed regions. Among ligand properties, we observe increased protein flexibility as the number of hydrogen bonds decreases and relative hydrophobicity increases. Across a series of 13 inhibitor-bound structures of CDK2, we find that conformational heterogeneity is correlated with inhibitor features and identify how conformational changes propagate differences in conformational heterogeneity away from the binding site. Collectively, our findings agree with models emerging from nuclear magnetic resonance studies suggesting that residual side-chain entropy can modulate affinity and point to the need to integrate both static conformational changes and conformational heterogeneity in models of ligand binding.
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Affiliation(s)
- Stephanie A Wankowicz
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
- Biophysics Graduate Program, University of California San FranciscoSan FranciscoUnited States
| | | | - Daniel W Hogan
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Henry van den Bedem
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
- Atomwise Inc.San FranciscoUnited States
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
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26
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Shi H, Kimsey IJ, Gu S, Liu HF, Pham U, Schumacher MA, Al-Hashimi HM. Revealing A-T and G-C Hoogsteen base pairs in stressed protein-bound duplex DNA. Nucleic Acids Res 2021; 49:12540-12555. [PMID: 34792150 PMCID: PMC8643651 DOI: 10.1093/nar/gkab936] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 09/25/2021] [Accepted: 11/14/2021] [Indexed: 11/17/2022] Open
Abstract
Watson–Crick base pairs (bps) are the fundamental unit of genetic information and the building blocks of the DNA double helix. However, A-T and G-C can also form alternative ‘Hoogsteen’ bps, expanding the functional complexity of DNA. We developed ‘Hoog-finder’, which uses structural fingerprints to rapidly screen Hoogsteen bps, which may have been mismodeled as Watson–Crick in crystal structures of protein–DNA complexes. We uncovered 17 Hoogsteen bps, 7 of which were in complex with 6 proteins never before shown to bind Hoogsteen bps. The Hoogsteen bps occur near mismatches, nicks and lesions and some appear to participate in recognition and damage repair. Our results suggest a potentially broad role for Hoogsteen bps in stressed regions of the genome and call for a community-wide effort to identify these bps in current and future crystal structures of DNA and its complexes.
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Affiliation(s)
- Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Isaac J Kimsey
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Stephanie Gu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hsuan-Fu Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Uyen Pham
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Hashim M Al-Hashimi
- Department of Chemistry, Duke University, Durham, NC 27710, USA.,Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
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27
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Enríquez P, Krajewski K, Strahl BD, Rothbart SB, Dowen RH, Rose RB. Binding specificity and function of the SWI/SNF subunit SMARCA4 bromodomain interaction with acetylated histone H3K14. J Biol Chem 2021; 297:101145. [PMID: 34473995 PMCID: PMC8506967 DOI: 10.1016/j.jbc.2021.101145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 11/30/2022] Open
Abstract
Bromodomains (BD) are conserved reader modules that bind acetylated lysine residues on histones. Although much has been learned regarding the in vitro properties of these domains, less is known about their function within chromatin complexes. SWI/SNF chromatin-remodeling complexes modulate transcription and contribute to DNA damage repair. Mutations in SWI/SNF subunits have been implicated in many cancers. Here we demonstrate that the BD of Caenorhabditis elegans SMARCA4/BRG1, a core SWI/SNF subunit, recognizes acetylated lysine 14 of histone H3 (H3K14ac), similar to its Homo sapiens ortholog. We identify the interactions of SMARCA4 with the acetylated histone peptide from a 1.29 Å-resolution crystal structure of the CeSMARCA4 BD-H3K14ac complex. Significantly, most of the SMARCA4 BD residues in contact with the histone peptide are conserved with other proteins containing family VIII bromodomains. Based on the premise that binding specificity is conserved among bromodomain orthologs, we propose that loop residues outside of the binding pocket position contact residues to recognize the H3K14ac sequence. CRISPR-Cas9-mediated mutations in the SMARCA4 BD that abolish H3K14ac binding in vitro had little or no effect on C. elegans viability or physiological function in vivo. However, combining SMARCA4 BD mutations with knockdown of the SWI/SNF accessory subunit PBRM-1 resulted in severe developmental defects in animals. In conclusion, we demonstrated an essential function for the SWI/SNF bromodomain in vivo and detected potential redundancy in epigenetic readers in regulating chromatin remodeling. These findings have implications for the development of small-molecule BD inhibitors to treat cancers and other diseases.
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Affiliation(s)
- Paul Enríquez
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA
| | - Krzysztof Krajewski
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Brian D Strahl
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Scott B Rothbart
- Department of Epigenetics, Van Andel Institute, Grand Rapids, Michigan, USA
| | - Robert H Dowen
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Robert B Rose
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina, USA.
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28
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Bradford SYC, El Khoury L, Ge Y, Osato M, Mobley DL, Fischer M. Temperature artifacts in protein structures bias ligand-binding predictions. Chem Sci 2021; 12:11275-11293. [PMID: 34667539 PMCID: PMC8447925 DOI: 10.1039/d1sc02751d] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/09/2021] [Indexed: 12/14/2022] Open
Abstract
X-ray crystallography is the gold standard to resolve conformational ensembles that are significant for protein function, ligand discovery, and computational methods development. However, relevant conformational states may be missed at common cryogenic (cryo) data-collection temperatures but can be populated at room temperature. To assess the impact of temperature on making structural and computational discoveries, we systematically investigated protein conformational changes in response to temperature and ligand binding in a structural and computational workhorse, the T4 lysozyme L99A cavity. Despite decades of work on this protein, shifting to RT reveals new global and local structural changes. These include uncovering an apo helix conformation that is hidden at cryo but relevant for ligand binding, and altered side chain and ligand conformations. To evaluate the impact of temperature-induced protein and ligand changes on the utility of structural information in computation, we evaluated how temperature can mislead computational methods that employ cryo structures for validation. We find that when comparing simulated structures just to experimental cryo structures, hidden successes and failures often go unnoticed. When using structural information in ligand binding predictions, both coarse docking and rigorous binding free energy calculations are influenced by temperature effects. The trend that cryo artifacts limit the utility of structures for computation holds across five distinct protein classes. Our results suggest caution when consulting cryogenic structural data alone, as temperature artifacts can conceal errors and prevent successful computational predictions, which can mislead the development and application of computational methods in discovering bioactive molecules.
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Affiliation(s)
- Shanshan Y C Bradford
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital Memphis TN 38105 USA
| | - Léa El Khoury
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Yunhui Ge
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - Meghan Osato
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
| | - David L Mobley
- Department of Pharmaceutical Sciences, University of California Irvine CA 92697 USA
- Department of Chemistry, University of California Irvine CA 92697 USA
| | - Marcus Fischer
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital Memphis TN 38105 USA
- Department of Structural Biology, St. Jude Children's Research Hospital Memphis TN 38105 USA
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29
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Civera M, Moroni E, Sorrentino L, Vasile F, Sattin S. Chemical and Biophysical Approaches to Allosteric Modulation. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Monica Civera
- Department of Chemistry Università degli Studi di Milano via C. Golgi, 19 20133 Milan Italy
| | - Elisabetta Moroni
- Istituto di Scienze e Tecnologie Chimiche Giulio Natta, SCITEC Via Mario Bianco 9 20131 Milan Italy
| | - Luca Sorrentino
- Department of Chemistry Università degli Studi di Milano via C. Golgi, 19 20133 Milan Italy
| | - Francesca Vasile
- Department of Chemistry Università degli Studi di Milano via C. Golgi, 19 20133 Milan Italy
| | - Sara Sattin
- Department of Chemistry Università degli Studi di Milano via C. Golgi, 19 20133 Milan Italy
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30
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Abstract
In this minireview we discuss the role of the more subtle conformational change-protein conformational sampling and connect it to the classic relationship of protein structure and function. The theory of pre-existing functional states of protein are discussed in context of alternate protein conformational sampling. Last, we discuss how temperature, ligand binding and mutations affect the protein conformational sampling mode which is linked to the protein function regulation. The review includes several protein systems that showed temperature dependent protein conformational sampling. We also specifically included two enzyme systems, thermophilic alcohol dehydrogenase (ht-ADH) and thermolysin which we previously studied when discussing temperature dependent protein conformational sampling.
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Affiliation(s)
- Ming Dong
- Department of Chemistry, North Carolina Agricultural and Technical State University, 1601 E Market Street, Greensboro, NC, 27410, USA.
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31
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32
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Miletic S, Fahrenkamp D, Goessweiner-Mohr N, Wald J, Pantel M, Vesper O, Kotov V, Marlovits TC. Substrate-engaged type III secretion system structures reveal gating mechanism for unfolded protein translocation. Nat Commun 2021; 12:1546. [PMID: 33750771 PMCID: PMC7943601 DOI: 10.1038/s41467-021-21143-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 01/06/2021] [Indexed: 02/06/2023] Open
Abstract
Many bacterial pathogens rely on virulent type III secretion systems (T3SSs) or injectisomes to translocate effector proteins in order to establish infection. The central component of the injectisome is the needle complex which assembles a continuous conduit crossing the bacterial envelope and the host cell membrane to mediate effector protein translocation. However, the molecular principles underlying type III secretion remain elusive. Here, we report a structure of an active Salmonella enterica serovar Typhimurium needle complex engaged with the effector protein SptP in two functional states, revealing the complete 800Å-long secretion conduit and unraveling the critical role of the export apparatus (EA) subcomplex in type III secretion. Unfolded substrates enter the EA through a hydrophilic constriction formed by SpaQ proteins, which enables side chain-independent substrate transport. Above, a methionine gasket formed by SpaP proteins functions as a gate that dilates to accommodate substrates while preventing leaky pore formation. Following gate penetration, a moveable SpaR loop first folds up to then support substrate transport. Together, these findings establish the molecular basis for substrate translocation through T3SSs and improve our understanding of bacterial pathogenicity and motility.
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Affiliation(s)
- Sean Miletic
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany.,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.,Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Dirk Fahrenkamp
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
| | - Nikolaus Goessweiner-Mohr
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany.,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.,Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Jiri Wald
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany.,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.,Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Maurice Pantel
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany
| | - Oliver Vesper
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany.,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.,Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Vadim Kotov
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany.,Centre for Structural Systems Biology (CSSB), Hamburg, Germany.,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany.,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria.,Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Thomas C Marlovits
- University Medical Center Hamburg-Eppendorf (UKE), Institute of Structural and Systems Biology, Hamburg, Germany. .,Centre for Structural Systems Biology (CSSB), Hamburg, Germany. .,Deutsches Elektronen-Synchrotron Zentrum (DESY), Hamburg, Germany. .,Institute of Molecular Biotechnology GmbH (IMBA), Austrian Academy of Sciences, Vienna, Austria. .,Research Institute of Molecular Pathology (IMP), Vienna, Austria.
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33
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Abstract
X-ray crystallography enables detailed structural studies of proteins to understand and modulate their function. Conducting crystallographic experiments at cryogenic temperatures has practical benefits but potentially limits the identification of functionally important alternative protein conformations that can be revealed only at room temperature (RT). This review discusses practical aspects of preparing, acquiring, and analyzing X-ray crystallography data at RT to demystify preconceived impracticalities that freeze progress of routine RT data collection at synchrotron sources. Examples are presented as conceptual and experimental templates to enable the design of RT-inspired studies; they illustrate the diversity and utility of gaining novel insights into protein conformational landscapes. An integrative view of protein conformational dynamics enables opportunities to advance basic and biomedical research.
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34
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Riley BT, Wankowicz SA, de Oliveira SHP, van Zundert GCP, Hogan DW, Fraser JS, Keedy DA, van den Bedem H. qFit 3: Protein and ligand multiconformer modeling for X-ray crystallographic and single-particle cryo-EM density maps. Protein Sci 2021; 30:270-285. [PMID: 33210433 PMCID: PMC7737783 DOI: 10.1002/pro.4001] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 01/04/2023]
Abstract
New X-ray crystallography and cryo-electron microscopy (cryo-EM) approaches yield vast amounts of structural data from dynamic proteins and their complexes. Modeling the full conformational ensemble can provide important biological insights, but identifying and modeling an internally consistent set of alternate conformations remains a formidable challenge. qFit efficiently automates this process by generating a parsimonious multiconformer model. We refactored qFit from a distributed application into software that runs efficiently on a small server, desktop, or laptop. We describe the new qFit 3 software and provide some examples. qFit 3 is open-source under the MIT license, and is available at https://github.com/ExcitedStates/qfit-3.0.
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Affiliation(s)
- Blake T. Riley
- Structural Biology InitiativeCUNY Advanced Science Research CenterNew YorkNew YorkUSA
| | - Stephanie A. Wankowicz
- Department of Bioengineering and Therapeutic SciencesUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Biophysics Graduate ProgramUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | | | | | - Daniel W. Hogan
- Department of Bioengineering and Therapeutic SciencesUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - James S. Fraser
- Department of Bioengineering and Therapeutic SciencesUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Daniel A. Keedy
- Structural Biology InitiativeCUNY Advanced Science Research CenterNew YorkNew YorkUSA
- Department of Chemistry and BiochemistryCity College of New YorkNew YorkNew YorkUSA
- Ph.D. Programs in Biochemistry, Biology, and ChemistryThe Graduate Center, City University of New YorkNew YorkUSA
| | - Henry van den Bedem
- Department of Bioengineering and Therapeutic SciencesUniversity of California San FranciscoSan FranciscoCaliforniaUSA
- Atomwise, Inc.San FranciscoCaliforniaUSA
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35
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Doukov T, Herschlag D, Yabukarski F. Instrumentation and experimental procedures for robust collection of X-ray diffraction data from protein crystals across physiological temperatures. J Appl Crystallogr 2020; 53:1493-1501. [PMID: 33312102 DOI: 10.1107/s1600576720013503] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/08/2020] [Indexed: 11/10/2022] Open
Abstract
Traditional X-ray diffraction data collected at cryo-temperatures have delivered invaluable insights into the three-dimensional structures of proteins, providing the backbone of structure-function studies. While cryo-cooling mitigates radiation damage, cryo-temperatures can alter protein conformational ensembles and solvent structure. Furthermore, conformational ensembles underlie protein function and energetics, and recent advances in room-temperature X-ray crystallography have delivered conformational heterogeneity information that can be directly related to biological function. Given this capability, the next challenge is to develop a robust and broadly applicable method to collect single-crystal X-ray diffraction data at and above room temperature. This challenge is addressed herein. The approach described provides complete diffraction data sets with total collection times as short as ∼5 s from single protein crystals, dramatically increasing the quantity of data that can be collected within allocated synchrotron beam time. Its applicability was demonstrated by collecting 1.09-1.54 Å resolution data over a temperature range of 293-363 K for proteinase K, thaumatin and lysozyme crystals at BL14-1 at the Stanford Synchrotron Radiation Lightsource. The analyses presented here indicate that the diffraction data are of high quality and do not suffer from excessive dehydration or radiation damage.
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Affiliation(s)
- Tzanko Doukov
- SMB, Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA.,Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.,Stanford ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Filip Yabukarski
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA
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36
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Krojer T, Fraser JS, von Delft F. Discovery of allosteric binding sites by crystallographic fragment screening. Curr Opin Struct Biol 2020; 65:209-216. [PMID: 33171388 PMCID: PMC10979522 DOI: 10.1016/j.sbi.2020.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 02/02/2023]
Abstract
Understanding allosteric regulation of proteins is fundamental to our study of protein structure and function. Moreover, allosteric binding pockets have become a major target of drug discovery efforts in recent years. However, even though the function of almost every protein can be influenced by allostery, it remains a challenge to discover, rationalise and validate putative allosteric binding pockets. This review examines how the discovery and analysis of putative allosteric binding sites have been influenced by the availability of centralised facilities for crystallographic fragment screening, along with newly developed computational methods for modelling low occupancy features. We discuss the experimental parameters required for success, and how new methods could influence the field in the future. Finally, we reflect on the general problem of how to translate these findings into actual ligand development programs.
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Affiliation(s)
- Tobias Krojer
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA; Quantitative Biosciences Institute, University of California San Francisco, San Francisco, CA, USA
| | - Frank von Delft
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK; Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0QX, UK; Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot OX11 0FA, UK; Department of Biochemistry, University of Johannesburg, Auckland Park, 2006, South Africa.
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37
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Wu S, Nguyen TTTN, Moroz OV, Turkenburg JP, Nielsen JE, Wilson KS, Rand KD, Teilum K. Conformational heterogeneity of Savinase from NMR, HDX-MS and X-ray diffraction analysis. PeerJ 2020; 8:e9408. [PMID: 32617193 PMCID: PMC7323712 DOI: 10.7717/peerj.9408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
Background Several examples have emerged of enzymes where slow conformational changes are of key importance for function and where low populated conformations in the resting enzyme resemble the conformations of intermediate states in the catalytic process. Previous work on the subtilisin protease, Savinase, from Bacillus lentus by NMR spectroscopy suggested that this enzyme undergoes slow conformational dynamics around the substrate binding site. However, the functional importance of such dynamics is unknown. Methods Here we have probed the conformational heterogeneity in Savinase by following the temperature dependent chemical shift changes. In addition, we have measured changes in the local stability of the enzyme when the inhibitor phenylmethylsulfonyl fluoride is bound using hydrogen-deuterium exchange mass spectrometry (HDX-MS). Finally, we have used X-ray crystallography to compare electron densities collected at cryogenic and ambient temperatures and searched for possible low populated alternative conformations in the crystals. Results The NMR temperature titration shows that Savinase is most flexible around the active site, but no distinct alternative states could be identified. The HDX shows that modification of Savinase with inhibitor has very little impact on the stability of hydrogen bonds and solvent accessibility of the backbone. The most pronounced structural heterogeneities detected in the diffraction data are limited to alternative side-chain rotamers and a short peptide segment that has an alternative main-chain conformation in the crystal at cryo conditions. Collectively, our data show that there is very little structural heterogeneity in the resting state of Savinase and hence that Savinase does not rely on conformational selection to drive the catalytic process.
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Affiliation(s)
- Shanshan Wu
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
| | - Tam T T N Nguyen
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Copenhagen Ø, Denmark
| | - Olga V Moroz
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | - Johan P Turkenburg
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | | | - Keith S Wilson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | - Kasper D Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Copenhagen Ø, Denmark
| | - Kaare Teilum
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen N, Denmark
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38
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Abstract
Recent technical advances have dramatically increased the power and scope of structural biology. New developments in high-resolution cryo-electron microscopy, serial X-ray crystallography, and electron diffraction have been especially transformative. Here we highlight some of the latest advances and current challenges at the frontiers of atomic resolution methods for elucidating the structures and dynamical properties of macromolecules and their complexes.
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Affiliation(s)
- Michael C. Thompson
- Department of Chemistry and Chemical Biology, University of California, Merced, CA, USA
| | - Todd O. Yeates
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
| | - Jose A. Rodriguez
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
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39
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Silvestri I, Lyu H, Fata F, Banta PR, Mattei B, Ippoliti R, Bellelli A, Pitari G, Ardini M, Petukhova V, Thatcher GRJ, Petukhov PA, Williams DL, Angelucci F. Ectopic suicide inhibition of thioredoxin glutathione reductase. Free Radic Biol Med 2020; 147:200-211. [PMID: 31870799 PMCID: PMC7583042 DOI: 10.1016/j.freeradbiomed.2019.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/13/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Selective suicide inhibitors represent a seductively attractive approach for inactivation of therapeutically relevant enzymes since they are generally devoid of off-target toxicity in vivo. While most suicide inhibitors are converted to reactive species at enzyme active sites, theoretically bioactivation can also occur in ectopic (secondary) sites that have no known function. Here, we report an example of such an "ectopic suicide inhibition", an unprecedented bioactivation mechanism of a suicide inhibitor carried out by a non-catalytic site of thioredoxin glutathione reductase (TGR). TGR is a promising drug target to treat schistosomiasis, a devastating human parasitic disease. Utilizing hits selected from a high throughput screening campaign, time-resolved X-ray crystallography, molecular dynamics, mass spectrometry, molecular modeling, protein mutagenesis and functional studies, we find that 2-naphtholmethylamino derivatives bound to this novel ectopic site of Schistosoma mansoni (Sm)TGR are transformed to covalent modifiers and react with its mobile selenocysteine-containing C-terminal arm. In particular, one 2-naphtholmethylamino compound is able to specifically induce the pro-oxidant activity in the inhibited enzyme. Since some 2-naphtholmethylamino analogues show worm killing activity and the ectopic site is not conserved in human orthologues, a general approach to development of novel and selective anti-parasitic therapeutics against schistosoma is proposed.
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Affiliation(s)
- Ilaria Silvestri
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Haining Lyu
- Dept. of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL, USA
| | - Francesca Fata
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Paul R Banta
- Dept. of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL, USA
| | - Benedetta Mattei
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Rodolfo Ippoliti
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Andrea Bellelli
- Dept. of Biochemical Sciences, Sapienza University of Rome, Italy
| | - Giuseppina Pitari
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Matteo Ardini
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy
| | - Valentina Petukhova
- Dept. of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Gregory R J Thatcher
- Dept. of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Pavel A Petukhov
- Dept. of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA.
| | - David L Williams
- Dept. of Microbial Pathogens and Immunity, Rush University Medical Center, Chicago, IL, USA.
| | - Francesco Angelucci
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Italy.
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40
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Dong M, Lauro ML, Koblish TJ, Bahnson BJ. Conformational sampling and kinetics changes across a non-Arrhenius break point in the enzyme thermolysin. Struct Dyn 2020; 7:014101. [PMID: 32095489 PMCID: PMC7021514 DOI: 10.1063/1.5130582] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 01/01/2020] [Indexed: 06/10/2023]
Abstract
Numerous studies have suggested a significant role that protein dynamics play in optimizing enzyme catalysis, and changes in conformational sampling offer a window to explore this role. Thermolysin from Bacillus thermoproteolyticus rokko, which is a heat-stable zinc metalloproteinase, serves here as a model system to study changes of protein function and conformational sampling across a temperature range of 16-36 °C. The temperature dependence of kinetics of thermolysin showed a biphasic transition at 26 °C that points to potential conformational and dynamic differences across this temperature. The non-Arrhenius behavior observed resembled results from previous studies of a thermophilic alcohol dehydrogenase enzyme, which also indicated a biphasic transition at ambient temperatures. To explore the non-Arrhenius behavior of thermolysin, room temperature crystallography was applied to characterize structural changes in a temperature range across the biphasic transition temperature. The alternate conformation of side chain fitting to electron density of a group of residues showed a higher variability in the temperature range from 26 to 29 °C, which indicated a change in conformational sampling that correlated with the non-Arrhenius break point.
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Affiliation(s)
- Ming Dong
- Department of Chemistry, North Carolina A&T State University, Greensboro, North Carolina 27411, USA
| | - Mackenzie L. Lauro
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Timothy J. Koblish
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | - Brian J. Bahnson
- Department of Chemistry & Biochemistry, University of Delaware, Newark, Delaware 19716, USA
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41
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Holt GT, Jou JD, Gill NP, Lowegard AU, Martin JW, Madden DR, Donald BR. Computational Analysis of Energy Landscapes Reveals Dynamic Features That Contribute to Binding of Inhibitors to CFTR-Associated Ligand. J Phys Chem B 2019; 123:10441-10455. [PMID: 31697075 DOI: 10.1021/acs.jpcb.9b07278] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The CFTR-associated ligand PDZ domain (CALP) binds to the cystic fibrosis transmembrane conductance regulator (CFTR) and mediates lysosomal degradation of mature CFTR. Inhibition of this interaction has been explored as a therapeutic avenue for cystic fibrosis. Previously, we reported the ensemble-based computational design of a novel peptide inhibitor of CALP, which resulted in the most binding-efficient inhibitor to date. This inhibitor, kCAL01, was designed using osprey and evinced significant biological activity in in vitro cell-based assays. Here, we report a crystal structure of kCAL01 bound to CALP and compare structural features against iCAL36, a previously developed inhibitor of CALP. We compute side-chain energy landscapes for each structure to not only enable approximation of binding thermodynamics but also reveal ensemble features that contribute to the comparatively efficient binding of kCAL01. Finally, we compare the previously reported design ensemble for kCAL01 vs the new crystal structure and show that, despite small differences between the design model and crystal structure, significant biophysical features that enhance inhibitor binding are captured in the design ensemble. This suggests not only that ensemble-based design captured thermodynamically significant features observed in vitro, but also that a design eschewing ensembles would miss the kCAL01 sequence entirely.
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Affiliation(s)
- Graham T Holt
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Program in Computational Biology and Bioinformatics , Duke University , Durham , North Carolina 27708 , United States
| | - Jonathan D Jou
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States
| | - Nicholas P Gill
- Department of Biochemistry & Cell Biology , Geisel School of Medicine at Dartmouth , Hanover , New Hampshire 03755 , United States
| | - Anna U Lowegard
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Program in Computational Biology and Bioinformatics , Duke University , Durham , North Carolina 27708 , United States
| | - Jeffrey W Martin
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States
| | - Dean R Madden
- Department of Biochemistry & Cell Biology , Geisel School of Medicine at Dartmouth , Hanover , New Hampshire 03755 , United States
| | - Bruce R Donald
- Department of Computer Science , Duke University , Durham , North Carolina 27708 , United States.,Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States.,Department of Chemistry , Duke University , Durham , North Carolina 27710 , United States
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42
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Moreau DW, Atakisi H, Thorne RE. Solvent flows, conformation changes and lattice reordering in a cold protein crystal. Acta Crystallogr D Struct Biol 2019; 75:980-994. [PMID: 31692472 PMCID: PMC6834080 DOI: 10.1107/s2059798319013822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 10/10/2019] [Indexed: 11/10/2022] Open
Abstract
When protein crystals are abruptly cooled, the unit-cell, protein and solvent-cavity volumes all contract, but the volume of bulk-like internal solvent may expand. Outflow of this solvent from the unit cell and its accumulation in defective interior crystal regions has been suggested as one cause of the large increase in crystal mosaicity on cooling. It is shown that when apoferritin crystals are abruptly cooled to temperatures between 220 and 260 K, the unit cell contracts, solvent is pushed out and the mosaicity grows. On temperature-dependent timescales of 10 to 200 s, the unit-cell and solvent-cavity volume then expand, solvent flows back in, and the mosaicity and B factor both drop. Expansion and reordering at fixed low temperature are associated with small-amplitude but large-scale changes in the conformation and packing of apoferritin. These results demonstrate that increases in mosaicity on cooling arise due to solvent flows out of or into the unit cell and to incomplete, arrested relaxation of protein conformation. They indicate a critical role for time in variable-temperature crystallographic studies, and the feasibility of probing interactions and cooperative conformational changes that underlie cold denaturation in the presence of liquid solvent at temperatures down to ∼200 K.
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Affiliation(s)
- David W. Moreau
- Physics Department, Cornell University, Ithaca, NY 14853, USA
| | - Hakan Atakisi
- Physics Department, Cornell University, Ithaca, NY 14853, USA
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43
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Harrison K, Wu Z, Juers DH. A comparison of gas stream cooling and plunge cooling of macromolecular crystals. J Appl Crystallogr 2019; 52:1222-1232. [PMID: 31636524 PMCID: PMC6782077 DOI: 10.1107/s1600576719010318] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/18/2019] [Indexed: 01/17/2023] Open
Abstract
Cryocooling for macromolecular crystallography is usually performed via plunging the crystal into a liquid cryogen or placing the crystal in a cold gas stream. These two approaches are compared here for the case of nitro-gen cooling. The results show that gas stream cooling, which typically cools the crystal more slowly, yields lower mosaicity and, in some cases, a stronger anomalous signal relative to rapid plunge cooling. During plunging, moving the crystal slowly through the cold gas layer above the liquid surface can produce mosaicity similar to gas stream cooling. Annealing plunge cooled crystals by warming and recooling in the gas stream allows the mosaicity and anomalous signal to recover. For tetragonal thermolysin, the observed effects are less pronounced when the cryosolvent has smaller thermal contraction, under which conditions the protein structures from plunge cooled and gas stream cooled crystals are very similar. Finally, this work also demonstrates that the resolution dependence of the reflecting range is correlated with the cooling method, suggesting it may be a useful tool for discerning whether crystals are cooled too rapidly. The results support previous studies suggesting that slower cooling methods are less deleterious to crystal order, as long as ice formation is prevented and dehydration is limited.
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Affiliation(s)
- Kaitlin Harrison
- Department of Physics and Program in Biochemistry, Biophysics and Molecular Biology, Whitman College, 345 Boyer Avenue, Walla Walla, WA 99362, USA
| | - Zhenguo Wu
- Department of Physics and Program in Biochemistry, Biophysics and Molecular Biology, Whitman College, 345 Boyer Avenue, Walla Walla, WA 99362, USA
| | - Douglas H Juers
- Department of Physics and Program in Biochemistry, Biophysics and Molecular Biology, Whitman College, 345 Boyer Avenue, Walla Walla, WA 99362, USA
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44
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Santhosh R, Chandrasekaran P, Michael D, Rangachari K, Bankoti N, Jeyakanthan J, Sekar K. ACMS: a database of alternate conformations found in the atoms of main and side chains of protein structures. J Appl Crystallogr 2019. [DOI: 10.1107/s1600576719006447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Proteins are usually dynamic biological macromolecules, thereby exhibiting a large number of conformational ensembles which influence the association with their neighbours and interacting partners. Most of the side-chain atoms and a few main-chain atoms of the high-resolution crystal structures deposited in the Protein Data Bank adopt alternate conformations. This kind of conformational behaviour prompted the authors to explore the relationship, if any, between the alternate conformations and the function of the protein molecule. Thus, a knowledge base of the alternate conformations of the main- and side-chain atoms of protein structures has been developed. It provides a detailed description of the alternate conformations of various residues for more than 60 000 high-resolution crystal structures. The proposed knowledge base is very user friendly and has various flexible options. The knowledge base will be updated periodically and can be accessed at http://iris.physics.iisc.ac.in/acms.
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45
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Rasheed M, Clement N, Bhowmick A, Bajaj CL. Statistical Framework for Uncertainty Quantification in Computational Molecular Modeling. IEEE/ACM Trans Comput Biol Bioinform 2019; 16:1154-1167. [PMID: 29989988 PMCID: PMC6857703 DOI: 10.1109/tcbb.2017.2771240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
As computational modeling, simulation, and predictions are becoming integral parts of biomedical pipelines, it behooves us to emphasize the reliability of the computational protocol. For any reported quantity of interest (QOI), one must also compute and report a measure of the uncertainty or error associated with the QOI. This is especially important in molecular modeling, since in most practical applications the inputs to the computational protocol are often noisy, incomplete, or low-resolution. Unfortunately, currently available modeling tools do not account for uncertainties and their effect on the final QOIs with sufficient rigor. We have developed a statistical framework that expresses the uncertainty of the QOI as the probability that the reported value deviates from the true value by more than some user-defined threshold. First, we provide a theoretical approach where this probability can be bounded using Azuma-Hoeffding like inequalities. Second, we approximate this probability empirically by sampling the space of uncertainties of the input and provide applications of our framework to bound uncertainties of several QOIs commonly used in molecular modeling. Finally, we also present several visualization techniques to effectively and quantitavely visualize the uncertainties: in the input, final QOIs, and also intermediate states.
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46
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Batchelor M, Wolny M, Baker EG, Paci E, Kalverda AP, Peckham M. Dynamic ion pair behavior stabilizes single α-helices in proteins. J Biol Chem 2019; 294:3219-3234. [PMID: 30593502 PMCID: PMC6398138 DOI: 10.1074/jbc.ra118.006752] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 12/17/2018] [Indexed: 11/06/2022] Open
Abstract
Ion pairs are key stabilizing interactions between oppositely charged amino acid side chains in proteins. They are often depicted as single conformer salt bridges (hydrogen-bonded ion pairs) in crystal structures, but it is unclear how dynamic they are in solution. Ion pairs are thought to be particularly important in stabilizing single α-helix (SAH) domains in solution. These highly stable domains are rich in charged residues (such as Arg, Lys, and Glu) with potential ion pairs across adjacent turns of the helix. They provide a good model system to investigate how ion pairs can contribute to protein stability. Using NMR spectroscopy, small-angle X-ray light scattering (SAXS), and molecular dynamics simulations, we provide here experimental evidence that ion pairs exist in a SAH in murine myosin 7a (residues 858-935), but that they are not fixed or long lasting. In silico modeling revealed that the ion pairs within this α-helix exhibit dynamic behavior, rapidly forming and breaking and alternating between different partner residues. The low-energy helical state was compatible with a great variety of ion pair combinations. Flexible ion pair formation utilizing a subset of those available at any one time avoided the entropic penalty of fixing side chain conformations, which likely contributed to helix stability overall. These results indicate the dynamic nature of ion pairs in SAHs. More broadly, thermodynamic stability in other proteins is likely to benefit from the dynamic behavior of multi-option solvent-exposed ion pairs.
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Affiliation(s)
- Matthew Batchelor
- From the School of Molecular and Cellular Biology and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Marcin Wolny
- From the School of Molecular and Cellular Biology and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Emily G Baker
- the School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
| | - Emanuele Paci
- From the School of Molecular and Cellular Biology and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Arnout P Kalverda
- From the School of Molecular and Cellular Biology and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom and
| | - Michelle Peckham
- From the School of Molecular and Cellular Biology and the Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom and
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47
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Keedy DA. Journey to the center of the protein: allostery from multitemperature multiconformer X-ray crystallography. Acta Crystallogr D Struct Biol 2019; 75:123-137. [PMID: 30821702 PMCID: PMC6400254 DOI: 10.1107/s2059798318017941] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 12/19/2018] [Indexed: 02/08/2023] Open
Abstract
Proteins inherently fluctuate between conformations to perform functions in the cell. For example, they sample product-binding, transition-state-stabilizing and product-release states during catalysis, and they integrate signals from remote regions of the structure for allosteric regulation. However, there is a lack of understanding of how these dynamic processes occur at the basic atomic level. This gap can be at least partially addressed by combining variable-temperature (instead of traditional cryogenic temperature) X-ray crystallography with algorithms for modeling alternative conformations based on electron-density maps, in an approach called multitemperature multiconformer X-ray crystallography (MMX). Here, the use of MMX to reveal alternative conformations at different sites in a protein structure and to estimate the degree of energetic coupling between them is discussed. These insights can suggest testable hypotheses about allosteric mechanisms. Temperature is an easily manipulated experimental parameter, so the MMX approach is widely applicable to any protein that yields well diffracting crystals. Moreover, the general principles of MMX are extensible to other perturbations such as pH, pressure, ligand concentration etc. Future work will explore strategies for leveraging X-ray data across such perturbation series to more quantitatively measure how different parts of a protein structure are coupled to each other, and the consequences thereof for allostery and other aspects of protein function.
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Affiliation(s)
- Daniel A. Keedy
- Structural Biology Initiative, CUNY Advanced Science Research Center, New York, USA
- Department of Chemistry and Biochemistry, City College of New York, New York, USA
- PhD Programs in Chemistry and Biochemistry, The Graduate Center of the City University of New York, New York, USA
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48
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Sun Z, Liu Q, Qu G, Feng Y, Reetz MT. Utility of B-Factors in Protein Science: Interpreting Rigidity, Flexibility, and Internal Motion and Engineering Thermostability. Chem Rev 2019; 119:1626-1665. [PMID: 30698416 DOI: 10.1021/acs.chemrev.8b00290] [Citation(s) in RCA: 264] [Impact Index Per Article: 52.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Zhoutong Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Qian Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ge Qu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Manfred T. Reetz
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West Seventh Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Chemistry Department, Philipps-University, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany
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49
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van Zundert GCP, Hudson BM, de Oliveira SHP, Keedy DA, Fonseca R, Heliou A, Suresh P, Borrelli K, Day T, Fraser JS, van den Bedem H. qFit-ligand Reveals Widespread Conformational Heterogeneity of Drug-Like Molecules in X-Ray Electron Density Maps. J Med Chem 2018; 61:11183-11198. [PMID: 30457858 DOI: 10.1021/acs.jmedchem.8b01292] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Proteins and ligands sample a conformational ensemble that governs molecular recognition, activity, and dissociation. In structure-based drug design, access to this conformational ensemble is critical to understand the balance between entropy and enthalpy in lead optimization. However, ligand conformational heterogeneity is currently severely underreported in crystal structures in the Protein Data Bank, owing in part to a lack of automated and unbiased procedures to model an ensemble of protein-ligand states into X-ray data. Here, we designed a computational method, qFit-ligand, to automatically resolve conformationally averaged ligand heterogeneity in crystal structures, and applied it to a large set of protein receptor-ligand complexes. In an analysis of the cancer related BRD4 domain, we found that up to 29% of protein crystal structures bound with drug-like molecules present evidence of unmodeled, averaged, relatively isoenergetic conformations in ligand-receptor interactions. In many retrospective cases, these alternate conformations were adventitiously exploited to guide compound design, resulting in improved potency or selectivity. Combining qFit-ligand with high-throughput screening or multitemperature crystallography could therefore augment the structure-based drug design toolbox.
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Affiliation(s)
| | - Brandi M Hudson
- Department of Bioengineering and Therapeutic Sciences , UCSF , San Francisco , California 94158 , United States
| | - Saulo H P de Oliveira
- SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 United States
| | - Daniel A Keedy
- Department of Bioengineering and Therapeutic Sciences , UCSF , San Francisco , California 94158 , United States
| | - Rasmus Fonseca
- Department of Molecular and Cellular Physiology , Stanford University , Stanford , California 94305 , United States
| | - Amelie Heliou
- LIX, Ecole Polytechnique, CNRS, Inria , Université Paris-Saclay , 91128 Palaiseau , France
| | - Pooja Suresh
- Department of Bioengineering and Therapeutic Sciences , UCSF , San Francisco , California 94158 , United States
| | | | - Tyler Day
- Schrödinger , New York , New York 10036 , United States
| | - James S Fraser
- Department of Bioengineering and Therapeutic Sciences , UCSF , San Francisco , California 94158 , United States
| | - Henry van den Bedem
- Department of Bioengineering and Therapeutic Sciences , UCSF , San Francisco , California 94158 , United States.,SLAC National Accelerator Laboratory , Stanford University , Menlo Park , California 94025 United States
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50
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Herzik MA, Fraser JS, Lander GC. A Multi-model Approach to Assessing Local and Global Cryo-EM Map Quality. Structure 2018; 27:344-358.e3. [PMID: 30449687 DOI: 10.1016/j.str.2018.10.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/17/2018] [Accepted: 10/10/2018] [Indexed: 02/06/2023]
Abstract
There does not currently exist a standardized indicator of how well cryo-EM-derived models represent the density from which they were generated. We present a straightforward methodology that utilizes freely available tools to generate a suite of independent models and to evaluate their convergence in an EM density. These analyses provide both a quantitative and qualitative assessment of the precision of the models and their representation of the density, respectively, while concurrently providing a platform for assessing both global and local EM map quality. We further use standardized datasets to provide an expected deviation within a suite of models refined against EM maps reported to be at 5 Å resolution or better. Associating multiple atomic models with a deposited EM map provides a rapid and accessible reporter of convergence, a strong indicator of highly resolved molecular detail, and is an important step toward an FSC-independent assessment of map and model quality.
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Affiliation(s)
- Mark A Herzik
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - James S Fraser
- Department of Bioengineering and Therapeutic Science and California Institute for Quantitative Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Gabriel C Lander
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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