1
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Tsushima S, Kretzschmar J, Doi H, Okuwaki K, Kaneko M, Mochizuki Y, Takao K. Towards tailoring hydrophobic interaction with uranyl(VI) oxygen for C-H activation. Chem Commun (Camb) 2024; 60:4769-4772. [PMID: 38563824 DOI: 10.1039/d4cc01030b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Bovine serum albumin (BSA) has a uranyl(VI) binding hotspot where uranium is tightly bound by three carboxylates. Uranyl oxygen is "soaked" into the hydrophobic core of BSA. Isopropyl hydrogen of Val is trapped near UO22+ and upon photoexcitation, C-H bond cleavage is initiated. A unique hydrophobic contact with "yl"-oxygen, as observed here, can be used to induce C-H activation.
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Affiliation(s)
- Satoru Tsushima
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, 01328, Germany.
- International Research Frontiers Initiative (IRFI), Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
| | - Jérôme Kretzschmar
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Dresden, 01328, Germany.
| | - Hideo Doi
- Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Tokyo, 171-8501, Japan
| | - Koji Okuwaki
- Department of Chemistry and Research Center for Smart Molecules, Rikkyo University, Tokyo, 171-8501, Japan
| | - Masashi Kaneko
- Department of Chemistry, Osaka University, Osaka, 560-0043, Japan
| | - Yuji Mochizuki
- Department of Chemistry, Osaka University, Osaka, 560-0043, Japan
- Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
| | - Koichiro Takao
- Laboratory for Zero-Carbon Energy, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, 152-8550, Japan
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2
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Stachowski TR, Fischer M. FLEXR: automated multi-conformer model building using electron-density map sampling. Acta Crystallogr D Struct Biol 2023; 79:354-367. [PMID: 37071395 PMCID: PMC10167668 DOI: 10.1107/s2059798323002498] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/13/2023] [Indexed: 04/19/2023] Open
Abstract
Protein conformational dynamics that may inform biology often lie dormant in high-resolution electron-density maps. While an estimated ∼18% of side chains in high-resolution models contain alternative conformations, these are underrepresented in current PDB models due to difficulties in manually detecting, building and inspecting alternative conformers. To overcome this challenge, we developed an automated multi-conformer modeling program, FLEXR. Using Ringer-based electron-density sampling, FLEXR builds explicit multi-conformer models for refinement. Thereby, it bridges the gap of detecting hidden alternate states in electron-density maps and including them in structural models for refinement, inspection and deposition. Using a series of high-quality crystal structures (0.8-1.85 Å resolution), we show that the multi-conformer models produced by FLEXR uncover new insights that are missing in models built either manually or using current tools. Specifically, FLEXR models revealed hidden side chains and backbone conformations in ligand-binding sites that may redefine protein-ligand binding mechanisms. Ultimately, the tool facilitates crystallographers with opportunities to include explicit multi-conformer states in their high-resolution crystallographic models. One key advantage is that such models may better reflect interesting higher energy features in electron-density maps that are rarely consulted by the community at large, which can then be productively used for ligand discovery downstream. FLEXR is open source and publicly available on GitHub at https://github.com/TheFischerLab/FLEXR.
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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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3
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Natural Products as Mcl-1 Inhibitors: A Comparative Study of Experimental and Computational Modelling Data. CHEMISTRY 2022. [DOI: 10.3390/chemistry4030067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The human myeloid leukemia cell differentiation protein (hMcl-1) is an anti-apoptotic multi-partner protein, belonging to the B-cell lymphoma-2 (Bcl-2) family of proteins. Studies have linked hMcl-1 alleviated expression with resistance to hemopoietic chemotherapeutics, which makes it a key drug target in blood cancers. However, most of the developed small- to medium-sized hMcl-1 inhibitors have typical off-target activity towards other members of the Bcl-2 family. To improve the hMcl-1 inhibitor design, especially exploring a suitable scaffold with pharmacophoric features, we focused on natural hMcl-1 inhibitors. To date, seven classes of natural compounds have been isolated, which display a low micromolar affinity for hMcl-1 and have limited biophysical studies. We screened hMcl-1 co-crystal structures, and identified nine co-crystal structures of hMcl-1 protein, which were later evaluated by multiple receptor conformations (which indicates that the differences between hMcl-1 in crystal structures are low (RMSD values between 0.52 and 1.13 Å, average RMSD of 0.638–0.888 Å, with a standard deviation of 0.102–0.185Å)), and multiple ligand conformations (which led to the selection of the PDB structure, 3WIX (RMSD value = 0.879 Å, standard deviation 0.116 Å), to accommodate various Mcl-1 ligands from a range of co-crystal PDB files) methods. Later, the three adopted docking methods were assessed for their ability to reproduce the conformation bound to the crystal as well as predict trends in Ki values based on calculated RMSD and docking energies. Iterative docking and clustering of the docked pose within ≤1.0 Å was used to evaluate the reproducibility of the adopted docking methods and compared with their experimentally determined hMcl-1 affinity data.
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4
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Mikhailovskii O, Xue Y, Skrynnikov NR. Modeling a unit cell: crystallographic refinement procedure using the biomolecular MD simulation platform Amber. IUCRJ 2022; 9:114-133. [PMID: 35059216 PMCID: PMC8733891 DOI: 10.1107/s2052252521011891] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/09/2021] [Indexed: 06/14/2023]
Abstract
A procedure has been developed for the refinement of crystallographic protein structures based on the biomolecular simulation program Amber. The procedure constructs a model representing a crystal unit cell, which generally contains multiple protein molecules and is fully hydrated with TIP3P water. Periodic boundary conditions are applied to the cell in order to emulate the crystal lattice. The refinement is conducted in the form of a specially designed short molecular-dynamics run controlled by the Amber ff14SB force field and the maximum-likelihood potential that encodes the structure-factor-based restraints. The new Amber-based refinement procedure has been tested on a set of 84 protein structures. In most cases, the new procedure led to appreciably lower R free values compared with those reported in the original PDB depositions or obtained by means of the industry-standard phenix.refine program. In particular, the new method has the edge in refining low-accuracy scrambled models. It has also been successful in refining a number of molecular-replacement models, including one with an r.m.s.d. of 2.15 Å. In addition, Amber-refined structures consistently show superior MolProbity scores. The new approach offers a highly realistic representation of protein-protein interactions in the crystal, as well as of protein-water interactions. It also offers a realistic representation of protein crystal dynamics (akin to ensemble-refinement schemes). Importantly, the method fully utilizes the information from the available diffraction data, while relying on state-of-the-art molecular-dynamics modeling to assist with those elements of the structure that do not diffract well (for example mobile loops or side chains). Finally, it should be noted that the protocol employs no tunable parameters, and the calculations can be conducted in a matter of several hours on desktop computers equipped with graphical processing units or using a designated web service.
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Affiliation(s)
- Oleg Mikhailovskii
- Laboratory of Biomolecular NMR, St Petersburg State University, St Petersburg 199034, Russian Federation
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Yi Xue
- School of Life Sciences, Tsinghua University, Beijing 100084, People's Republic of China
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, People's Republic of China
- Tsinghua University-Peking University Joint Center for Life Sciences, Tsinghua University, Beijing 100084, People's Republic of China
| | - Nikolai R Skrynnikov
- Laboratory of Biomolecular NMR, St Petersburg State University, St Petersburg 199034, Russian Federation
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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5
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de Vries I, Kwakman T, Lu XJ, Hekkelman ML, Deshpande M, Velankar S, Perrakis A, Joosten RP. New restraints and validation approaches for nucleic acid structures in PDB-REDO. Acta Crystallogr D Struct Biol 2021; 77:1127-1141. [PMID: 34473084 PMCID: PMC8411979 DOI: 10.1107/s2059798321007610] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 07/26/2021] [Indexed: 11/10/2022] Open
Abstract
The quality of macromolecular structure models crucially depends on refinement and validation targets, which optimally describe the expected chemistry. Commonly used software for these two procedures has been designed and developed in a protein-centric manner, resulting in relatively few established features for the refinement and validation of nucleic acid-containing structure models. Here, new nucleic acid-specific approaches implemented in PDB-REDO are described, including a new restraint model using noncovalent geometries (base-pair hydrogen bonding and base-pair stacking) as refinement targets. New validation routines are also presented, including a metric for Watson-Crick base-pair geometry normality (ZbpG). Applying the PDB-REDO pipeline with the new restraint model to the whole Protein Data Bank (PDB) demonstrates an overall positive effect on the quality of nucleic acid-containing structure models. Finally, we discuss examples of improvements in the geometry of specific nucleic acid structures in the PDB. The new PDB-REDO models and pipeline are available at https://pdb-redo.eu/.
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Affiliation(s)
- Ida de Vries
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tim Kwakman
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Maarten L. Hekkelman
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Mandar Deshpande
- Protein Data Bank in Europe (PDBe), European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL–EBI), Wellcome Genome Campus, Hinxton CB10 1SD, United Kingdom
| | - Sameer Velankar
- Protein Data Bank in Europe (PDBe), European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL–EBI), Wellcome Genome Campus, Hinxton CB10 1SD, United Kingdom
| | - Anastassis Perrakis
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Robbie P. Joosten
- Oncode Institute and Division of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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6
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Grabowski M, Macnar JM, Cymborowski M, Cooper DR, Shabalin IG, Gilski M, Brzezinski D, Kowiel M, Dauter Z, Rupp B, Wlodawer A, Jaskolski M, Minor W. Rapid response to emerging biomedical challenges and threats. IUCRJ 2021; 8:395-407. [PMID: 33953926 PMCID: PMC8086160 DOI: 10.1107/s2052252521003018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 03/22/2021] [Indexed: 05/13/2023]
Abstract
As part of the global mobilization to combat the present pandemic, almost 100 000 COVID-19-related papers have been published and nearly a thousand models of macromolecules encoded by SARS-CoV-2 have been deposited in the Protein Data Bank within less than a year. The avalanche of new structural data has given rise to multiple resources dedicated to assessing the correctness and quality of structural data and models. Here, an approach to evaluate the massive amounts of such data using the resource https://covid19.bioreproducibility.org is described, which offers a template that could be used in large-scale initiatives undertaken in response to future biomedical crises. Broader use of the described methodology could considerably curtail information noise and significantly improve the reproducibility of biomedical research.
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Affiliation(s)
- Marek Grabowski
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Joanna M. Macnar
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
- College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Warsaw, Poland
- Faculty of Chemistry, Biological and Chemical Research Center, University of Warsaw, Warsaw, Poland
| | - Marcin Cymborowski
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - David R. Cooper
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Ivan G. Shabalin
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Miroslaw Gilski
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Dariusz Brzezinski
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Computing Science, Poznan University of Technology, Poznan, Poland
| | - Marcin Kowiel
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Zbigniew Dauter
- Center for Structural Biology, National Cancer Institute, Frederick, Maryland, USA
| | - Bernhard Rupp
- k.-k Hofkristallamt, San Diego, California, USA
- Institute of Genetic Epidemiology, Medical University Innsbruck, Innsbruck, Austria
| | - Alexander Wlodawer
- Center for Structural Biology, National Cancer Institute, Frederick, Maryland, USA
| | - Mariusz Jaskolski
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, Poland
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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7
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Computational studies on cholinesterases: Strengthening our understanding of the integration of structure, dynamics and function. Neuropharmacology 2020; 179:108265. [DOI: 10.1016/j.neuropharm.2020.108265] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/21/2020] [Accepted: 07/27/2020] [Indexed: 12/17/2022]
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8
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Hendrickx J, Tran V, Sanejouand YH. Numerous severely twisted N-acetylglucosamine conformations found in the protein databank. Proteins 2020; 88:1376-1383. [PMID: 32506721 DOI: 10.1002/prot.25957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 11/11/2022]
Abstract
Taking advantage of the known planarity of the N-acetyl group of N-acetylglucosamine, an analysis of the quality of carbohydrate structures found in the protein databank was performed. Few obvious defects of the local geometry of the carbonyl group were observed. However, the N-acetyl group was often found in the less favorable cis conformation (12% of the cases). It was also found severely twisted in numerous instances, especially in structures with a resolution poorer than 1.9 Å determined between 2000 and 2015. Though the automated PDB-REDO procedure has proved able to improve nearly 85% of the structural models deposited to the PDB, and does prove able to cure most severely twisted conformations of the N-acetyl group, it fails to correct its high rate of cis conformations. More generally, for structures with a resolution poorer than 1.6 Å, it produces N-acetylglucosamine models in slightly poorer agreement with experimental data, as measured using real-space correlation coefficients. Significant improvements are thus still needed, at least as far as this carbohydrate structure is concerned.
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Affiliation(s)
| | - Vinh Tran
- UFIP, UMR CNRS 6286, Université de Nantes, Nantes, France
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9
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McManus TJ, Wells SA, Walker AB. Salt bridge impact on global rigidity and thermostability in thermophilic citrate synthase. Phys Biol 2019; 17:016002. [PMID: 31220825 DOI: 10.1088/1478-3975/ab2b5c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It has been suggested that structural rigidity is connected to thermostability, e.g. in enzymes from thermophilic microorganisms. We examine the importance of correctly handling salt bridges, and interactions which we term 'strong polars', when constructing the constraint network for global rigidity analysis in these systems. Through a comparison of rigidity in citrate synthases, we clarify the relationship between rigidity and thermostability. In particular, with our corrected handling of strong polar interactions, the difference in rigidity between mesophilic and thermophilic structures is detected more clearly than in previous studies. The increase in rigidity did not detract from the functional flexibility of the active site in all systems once their respective temperature range had been reached. We then examine the distribution of salt bridges in thermophiles that were previously unaccounted for in flexibility studies. We show that in hyperthermophiles these have stabilising roles in the active site; occuring in close proximity to key residues involved in catalysis and binding of the protein.
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Affiliation(s)
- T J McManus
- Department of Physics, University of Bath, Bath, BA2 7AY, United Kingdom
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10
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Macchiagodena M, Pagliai M, Andreini C, Rosato A, Procacci P. Upgrading and Validation of the AMBER Force Field for Histidine and Cysteine Zinc(II)-Binding Residues in Sites with Four Protein Ligands. J Chem Inf Model 2019; 59:3803-3816. [PMID: 31385702 DOI: 10.1021/acs.jcim.9b00407] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We developed and validated a novel force field in the context of the AMBER parameterization for the simulation of zinc(II)-binding proteins. The proposed force field assumes nonbonded spherical interactions between the central zinc(II) and the coordinating residues. A crucial innovative aspect of our approach is to account for the polarization effects of the cation by redefining the atomic charges of the coordinating residues and an adjustment of Lennard-Jones parameters of Zn-interacting atoms to reproduce mean distance distributions. The optimal transferable parametrization was obtained by performing accurate quantum mechanical calculations on a training set of high-quality protein structures, encompassing the most common folds of zinc(II) sites. The addressed sites contain a zinc(II) ion tetra-coordinated by histidine and cysteine residues and represent about 70% of all physiologically relevant zinc(II) sites in the Protein Data Bank. Molecular dynamics simulations with explicit solvent, carried out on several zinc(II)-binding proteins not included in the training set, show that our model for zinc(II) sites preserves the tetra-coordination of the metal site with remarkable stability, yielding zinc(II)-X mean distances similar to experimental data. Finally, the model was tested by evaluating the zinc(II)-binding affinities, using the alchemical free energy perturbation approach. The calculated dissociation constants correlate satisfactorily with the experimental counterpart demonstrating the validity and transferability of the proposed parameterization for zinc(II)-binding proteins.
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Affiliation(s)
- Marina Macchiagodena
- Dipartimento di Chimica "Ugo Schiff" , Università degli Studi di Firenze , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy
| | - Marco Pagliai
- Dipartimento di Chimica "Ugo Schiff" , Università degli Studi di Firenze , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy
| | - Claudia Andreini
- Dipartimento di Chimica "Ugo Schiff" , Università degli Studi di Firenze , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy.,Magnetic Resonance Center (CERM)-Università degli Studi di Firenze , Via L. Sacconi 6 , 50019 Sesto Fiorentino , Italy
| | - Antonio Rosato
- Dipartimento di Chimica "Ugo Schiff" , Università degli Studi di Firenze , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy.,Magnetic Resonance Center (CERM)-Università degli Studi di Firenze , Via L. Sacconi 6 , 50019 Sesto Fiorentino , Italy
| | - Piero Procacci
- Dipartimento di Chimica "Ugo Schiff" , Università degli Studi di Firenze , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy
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11
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Taylor R, Wood PA. A Million Crystal Structures: The Whole Is Greater than the Sum of Its Parts. Chem Rev 2019; 119:9427-9477. [PMID: 31244003 DOI: 10.1021/acs.chemrev.9b00155] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The founding in 1965 of what is now called the Cambridge Structural Database (CSD) has reaped dividends in numerous and diverse areas of chemical research. Each of the million or so crystal structures in the database was solved for its own particular reason, but collected together, the structures can be reused to address a multitude of new problems. In this Review, which is focused mainly on the last 10 years, we chronicle the contribution of the CSD to research into molecular geometries, molecular interactions, and molecular assemblies and demonstrate its value in the design of biologically active molecules and the solid forms in which they are delivered. Its potential in other commercially relevant areas is described, including gas storage and delivery, thin films, and (opto)electronics. The CSD also aids the solution of new crystal structures. Because no scientific instrument is without shortcomings, the limitations of CSD research are assessed. We emphasize the importance of maintaining database quality: notwithstanding the arrival of big data and machine learning, it remains perilous to ignore the principle of garbage in, garbage out. Finally, we explain why the CSD must evolve with the world around it to ensure it remains fit for purpose in the years ahead.
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Affiliation(s)
- Robin Taylor
- Cambridge Crystallographic Data Centre , 12 Union Road , Cambridge CB2 1EZ , United Kingdom
| | - Peter A Wood
- Cambridge Crystallographic Data Centre , 12 Union Road , Cambridge CB2 1EZ , United Kingdom
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12
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Bueno R, Dawson A, Hunter WN. An assessment of three human methylenetetrahydrofolate dehydrogenase/cyclohydrolase-ligand complexes following further refinement. Acta Crystallogr F Struct Biol Commun 2019; 75:148-152. [PMID: 30839287 PMCID: PMC6404858 DOI: 10.1107/s2053230x18018083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 12/20/2018] [Indexed: 11/10/2022] Open
Abstract
The enzymes involved in folate metabolism are key drug targets for cell-growth modulation, and accurate crystallographic structures provide templates to be exploited for structure-based ligand design. In this context, three ternary complex structures of human methylenetetrahydrofolate dehydrogenase/cyclohydrolase have been published [Schmidt et al. (2000), Biochemistry, 39, 6325-6335] and potentially represent starting points for the development of new antifolate inhibitors. However, an inspection of the models and the deposited data revealed deficiencies and raised questions about the validity of the structures. A number of inconsistencies relating to the publication were also identified. Additional refinement was carried out with the deposited data, seeking to improve the models and to then validate the complex structures or correct the record. In one case, the inclusion of the inhibitor in the structure was supported and alterations to the model allowed details of enzyme-ligand interactions to be described that had not previously been discussed. For one weak inhibitor, the data suggested that the ligand may adopt two poses in the binding site, both with few interactions with the enzyme. In the third case, that of a potent inhibitor, inconsistencies were noted in the assignment of the chemical structure and there was no evidence to support the inclusion of the ligand in the active site.
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Affiliation(s)
- Renata Bueno
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Alice Dawson
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - William N. Hunter
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
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13
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Novak WRP, West KHJ, Kirkman LMD, Brandt GS. Re-refinement of Plasmodium falciparum orotidine 5'-monophosphate decarboxylase provides a clearer picture of an important malarial drug target. Acta Crystallogr F Struct Biol Commun 2018; 74:664-668. [PMID: 30279319 PMCID: PMC6168774 DOI: 10.1107/s2053230x18010610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 07/23/2018] [Indexed: 11/11/2022] Open
Abstract
The development of antimalarial drugs remains a public health priority, and the orotidine 5'-monophosphate decarboxylase from Plasmodium falciparum (PfOMPDC) has great potential as a drug target. The crystallization of PfOMPDC with substrate bound represents an important advance for structure-based drug-design efforts [Tokuoka et al. (2008), J. Biochem. 143, 69-78]. The complex of the enzyme bound to the substrate OMP (PDB entry 2za1) would be of particular utility in this regard. However, re-refinement of this structure of the Michaelis complex shows that the bound ligand is the product rather than the substrate. Here, the re-refinement of a set of three structures, the apo enzyme and two versions of the product-bound form (PDB entries 2za1, 2za2 and 2za3), is reported. The improved geometry and fit of these structures to the observed electron density will enhance their utility in antimalarial drug design.
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Affiliation(s)
- Walter R. P. Novak
- Chemistry Department, Wabash College, 301 West Wabash Avenue, Crawfordsville, IN 47933, USA
| | - Korbin H. J. West
- Chemistry Department, Wabash College, 301 West Wabash Avenue, Crawfordsville, IN 47933, USA
| | - Lucy M. D. Kirkman
- Chemistry Department, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604, USA
| | - Gabriel S. Brandt
- Chemistry Department, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604, USA
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14
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The 3-D structure of VNG0258H/RosR - A haloarchaeal DNA-binding protein in its ionic shell. J Struct Biol 2018; 204:191-198. [PMID: 30110657 DOI: 10.1016/j.jsb.2018.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/05/2018] [Accepted: 08/09/2018] [Indexed: 11/21/2022]
Abstract
Protein-DNA interactions are highly dependent on salt concentration. To gain insight into how such interactions are maintained in the highly saline cytoplasm of halophilic archaea, we determined the 3-D structure of VNG0258H/RosR, the first haloarchaeal DNA-binding protein from the extreme halophilic archaeon Halobactrium salinarum. It is a dimeric winged-helix-turn-helix (wHTH) protein with unique features due to adaptation to the halophilic environment. As ions are major players in DNA binding processes, particularly in halophilic environments, we investigated the solution structure of the ionic envelope and located anions in the first shell around the protein in the crystal using anomalous scattering. Anions that were found to be tightly bound to residues in the positively charged DNA-binding site would probably be released upon DNA binding and will thus make significant contribution to the driving force of the binding process. Unexpectedly, ions were also found in a buried internal cavity connected to the external medium by a tunnel. Our structure lays a solid groundwork for future structural, computational and biochemical studies on complexes of the protein with cognate DNA sequences, with implications to protein-DNA interactions in hyper-saline environments.
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15
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Delbart F, Brams M, Gruss F, Noppen S, Peigneur S, Boland S, Chaltin P, Brandao-Neto J, von Delft F, Touw WG, Joosten RP, Liekens S, Tytgat J, Ulens C. An allosteric binding site of the α7 nicotinic acetylcholine receptor revealed in a humanized acetylcholine-binding protein. J Biol Chem 2017; 293:2534-2545. [PMID: 29237730 PMCID: PMC5818190 DOI: 10.1074/jbc.m117.815316] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/24/2017] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) belong to the family of pentameric ligand-gated ion channels and mediate fast excitatory transmission in the central and peripheral nervous systems. Among the different existing receptor subtypes, the homomeric α7 nAChR has attracted considerable attention because of its possible implication in several neurological and psychiatric disorders, including cognitive decline associated with Alzheimer's disease or schizophrenia. Allosteric modulators of ligand-gated ion channels are of particular interest as therapeutic agents, as they modulate receptor activity without affecting normal fluctuations of synaptic neurotransmitter release. Here, we used X-ray crystallography and surface plasmon resonance spectroscopy of α7-acetylcholine-binding protein (AChBP), a humanized chimera of a snail AChBP, which has 71% sequence similarity with the extracellular ligand-binding domain of the human α7 nAChR, to investigate the structural determinants of allosteric modulation. We extended previous observations that an allosteric site located in the vestibule of the receptor offers an attractive target for receptor modulation. We introduced seven additional humanizing mutations in the vestibule-located binding site of AChBP to improve its suitability as a model for studying allosteric binding. Using a fragment-based screening approach, we uncovered an allosteric binding site located near the β8-β9 loop, which critically contributes to coupling ligand binding to channel opening in human α7 nAChR. This work expands our understanding of the topology of allosteric binding sites in AChBP and, by extrapolation, in the human α7 nAChR as determined by electrophysiology measurements. Our insights pave the way for drug design strategies targeting nAChRs involved in ion channel-mediated disorders.
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Affiliation(s)
- Florian Delbart
- From the Department of Cellular and Molecular Medicine, Laboratory of Structural Neurobiology, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Marijke Brams
- From the Department of Cellular and Molecular Medicine, Laboratory of Structural Neurobiology, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Fabian Gruss
- From the Department of Cellular and Molecular Medicine, Laboratory of Structural Neurobiology, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Sam Noppen
- the Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium
| | - Steve Peigneur
- the Laboratory of Toxicology and Pharmacology, Faculty of Pharmaceutical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Sandro Boland
- the Center for Innovation and Stimulation of Drug Discovery Leuven, Cistim Leuven vzw, 3001 Heverlee, Belgium
| | - Patrick Chaltin
- the Center for Innovation and Stimulation of Drug Discovery Leuven, Cistim Leuven vzw, 3001 Heverlee, Belgium.,the Center for Innovation and Stimulation of Drug Discovery Leuven and Center for Drug Design and Discovery, KU Leuven, 3001 Heverlee, Belgium
| | - Jose Brandao-Neto
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0QX, United Kingdom, and
| | - Frank von Delft
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot OX11 0QX, United Kingdom, and
| | - Wouter G Touw
- the Division of Biochemistry, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Robbie P Joosten
- the Division of Biochemistry, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Sandra Liekens
- the Department of Microbiology and Immunology, Laboratory of Virology and Chemotherapy, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium
| | - Jan Tytgat
- the Laboratory of Toxicology and Pharmacology, Faculty of Pharmaceutical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Chris Ulens
- From the Department of Cellular and Molecular Medicine, Laboratory of Structural Neurobiology, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium,
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16
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Christensen EM, Patel SM, Korasick DA, Campbell AC, Krause KL, Becker DF, Tanner JJ. Resolving the cofactor-binding site in the proline biosynthetic enzyme human pyrroline-5-carboxylate reductase 1. J Biol Chem 2017; 292:7233-7243. [PMID: 28258219 PMCID: PMC5409489 DOI: 10.1074/jbc.m117.780288] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 02/27/2017] [Indexed: 01/22/2023] Open
Abstract
Pyrroline-5-carboxylate reductase (PYCR) is the final enzyme in proline biosynthesis, catalyzing the NAD(P)H-dependent reduction of Δ1-pyrroline-5-carboxylate (P5C) to proline. Mutations in the PYCR1 gene alter mitochondrial function and cause the connective tissue disorder cutis laxa. Furthermore, PYCR1 is overexpressed in multiple cancers, and the PYCR1 knock-out suppresses tumorigenic growth, suggesting that PYCR1 is a potential cancer target. However, inhibitor development has been stymied by limited mechanistic details for the enzyme, particularly in light of a previous crystallographic study that placed the cofactor-binding site in the C-terminal domain rather than the anticipated Rossmann fold of the N-terminal domain. To fill this gap, we report crystallographic, sedimentation-velocity, and kinetics data for human PYCR1. Structures of binary complexes of PYCR1 with NADPH or proline determined at 1.9 Å resolution provide insight into cofactor and substrate recognition. We see NADPH bound to the Rossmann fold, over 25 Å from the previously proposed site. The 1.85 Å resolution structure of a ternary complex containing NADPH and a P5C/proline analog provides a model of the Michaelis complex formed during hydride transfer. Sedimentation velocity shows that PYCR1 forms a concentration-dependent decamer in solution, consistent with the pentamer-of-dimers assembly seen crystallographically. Kinetic and mutational analysis confirmed several features seen in the crystal structure, including the importance of a hydrogen bond between Thr-238 and the substrate as well as limited cofactor discrimination.
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Affiliation(s)
| | - Sagar M Patel
- the Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588
| | | | | | - Kurt L Krause
- the Department of Biochemistry, University of Otago, Dunedin 9054, New Zealand, and
| | - Donald F Becker
- the Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588
| | - John J Tanner
- From the Departments of Chemistry and
- Biochemistry University of Missouri, Columbia, Missouri 65211
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17
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Oliveira de Souza J, Dawson A, Hunter WN. An Improved Model of the Trypanosoma brucei CTP Synthetase Glutaminase Domain-Acivicin Complex. ChemMedChem 2017; 12:577-579. [PMID: 28333400 PMCID: PMC5413811 DOI: 10.1002/cmdc.201700118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/21/2017] [Indexed: 11/17/2022]
Abstract
The natural product acivicin inhibits the glutaminase activity of cytidine triphosphate (CTP) synthetase and is a potent lead compound for drug discovery in the area of neglected tropical diseases, specifically trypanosomaisis. A 2.1-Å-resolution crystal structure of the acivicin adduct with the glutaminase domain from Trypanosoma brucei CTP synthetase has been deposited in the RCSB Protein Data Bank (PDB) and provides a template for structure-based approaches to design new inhibitors. However, our assessment of that data identified deficiencies in the model. We now report an improved and corrected inhibitor structure with changes to the chirality at one position, the orientation and covalent structure of the isoxazoline moiety, and the location of a chloride ion in an oxyanion binding site that is exploited during catalysis. The model is now in agreement with established chemical principles and allows an accurate description of molecular recognition of the ligand and the mode of binding in a potentially valuable drug target.
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Affiliation(s)
- Juliana Oliveira de Souza
- Division of Biological Chemistry and Drug DiscoveryCollege of Life SciencesUniversity of DundeeDundeeDD1 5EHScotlandUK
| | - Alice Dawson
- Division of Biological Chemistry and Drug DiscoveryCollege of Life SciencesUniversity of DundeeDundeeDD1 5EHScotlandUK
| | - William N. Hunter
- Division of Biological Chemistry and Drug DiscoveryCollege of Life SciencesUniversity of DundeeDundeeDD1 5EHScotlandUK
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18
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Leonarski F, D'Ascenzo L, Auffinger P. Mg2+ ions: do they bind to nucleobase nitrogens? Nucleic Acids Res 2017; 45:987-1004. [PMID: 27923930 PMCID: PMC5314772 DOI: 10.1093/nar/gkw1175] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 01/28/2023] Open
Abstract
Given the many roles proposed for Mg2+ in nucleic acids, it is essential to accurately determine their binding modes. Here, we surveyed the PDB to classify Mg2+ inner-sphere binding patterns to nucleobase imine N1/N3/N7 atoms. Among those, purine N7 atoms are considered to be the best nucleobase binding sites for divalent metals. Further, Mg2+ coordination to N7 has been implied in several ribozyme catalytic mechanisms. We report that Mg2+ assigned near imine nitrogens derive mostly from poor interpretations of electron density patterns and are most often misidentified Na+, K+, NH4+ ions, water molecules or spurious density peaks. Consequently, apart from few documented exceptions, Mg2+ ions do not bind to N7 atoms. Without much of a surprise, Mn2+, Zn2+ and Cd2+, which have a higher affinity for nitrogens, may contact N7 atoms when present in crystallization buffers. In this respect, we describe for the first time a potential Zn2+ ribosomal binding site involving two purine N7 atoms. Further, we provide a set of guidelines to help in the assignment of Mg2+ in crystallographic, cryo-EM, NMR and model building practices and discuss implications of our findings related to ion substitution experiments.
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Affiliation(s)
- Filip Leonarski
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Luigi D'Ascenzo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Pascal Auffinger
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
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19
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Agirre J, Davies GJ, Wilson KS, Cowtan KD. Carbohydrate structure: the rocky road to automation. Curr Opin Struct Biol 2016; 44:39-47. [PMID: 27940408 DOI: 10.1016/j.sbi.2016.11.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 10/26/2016] [Accepted: 11/10/2016] [Indexed: 11/29/2022]
Abstract
With the introduction of intuitive graphical software, structural biologists who are not experts in crystallography are now able to build complete protein or nucleic acid models rapidly. In contrast, carbohydrates are in a wholly different situation: scant automation exists, with manual building attempts being sometimes toppled by incorrect dictionaries or refinement problems. Sugars are the most stereochemically complex family of biomolecules and, as pyranose rings, have clear conformational preferences. Despite this, all refinement programs may produce high-energy conformations at medium to low resolution, without any support from the electron density. This problem renders the affected structures unusable in glyco-chemical terms. Bringing structural glycobiology up to 'protein standards' will require a total overhaul of the methodology. Time is of the essence, as the community is steadily increasing the production rate of glycoproteins, and electron cryo-microscopy has just started to image them in precisely that resolution range where crystallographic methods falter most.
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Affiliation(s)
- Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
| | - Gideon J Davies
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK
| | - Keith S Wilson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK
| | - Kevin D Cowtan
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK.
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20
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Arulmozhiraja S, Matsuo N, Ishitsubo E, Okazaki S, Shimano H, Tokiwa H. Comparative Binding Analysis of Dipeptidyl Peptidase IV (DPP-4) with Antidiabetic Drugs - An Ab Initio Fragment Molecular Orbital Study. PLoS One 2016; 11:e0166275. [PMID: 27832184 PMCID: PMC5104442 DOI: 10.1371/journal.pone.0166275] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/25/2016] [Indexed: 02/07/2023] Open
Abstract
Dipeptidyl peptidase IV (DPP-4) enzyme is responsible for the degradation of incretins that stimulates insulin secretion and hence inhibition of DPP-4 becomes an established approach for the treatment of type 2 diabetics. We studied the interaction between DPP-4 and its inhibitor drugs (sitagliptin 1, linagliptin 2, alogliptin 3, and teneligliptin 4) quantitatively by using fragment molecular orbital calculations at the RI-MP2/cc-pVDZ level to analyze the inhibitory activities of the drugs. Apart from having common interactions with key residues, inhibitors encompassing the DPP-4 active site extensively interact widely with the hydrophobic pocket by their hydrophobic inhibitor moieties. The cumulative hydrophobic interaction becomes stronger for these inhibitors and hence linagliptin and teneligliptin have larger interaction energies, and consequently higher inhibitory activities, than their alogliptin and sitagliptin counterparts. Though effective interaction for both 2 and 3 is at [Formula: see text] subsite, 2 has a stronger binding to this subsite interacting with Trp629 and Tyr547 than 3 does. The presence of triazolopiperazine and piperazine moiety in 1 and 4, respectively, provides the interaction to the S2 extensive subsite; however, the latter's superior inhibitory activity is not only due to a relatively tighter binding to the S2 extensive subsite, but also due to the interactions to the S1 subsite. The calculated hydrophobic interfragment interaction energies correlate well with the experimental binding affinities (KD) and inhibitory activities (IC50) of the DPP-4 inhibitors.
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Affiliation(s)
- Sundaram Arulmozhiraja
- Department of Chemistry, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
- Research Center for Smart molecules, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
| | - Naoya Matsuo
- Department of Chemistry, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
| | - Erika Ishitsubo
- Department of Chemistry, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
| | - Seiji Okazaki
- Department of Chemistry, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
- Research Center for Smart molecules, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
| | - Hitoshi Shimano
- Department of Internal Medicine (Endocrinology and Metabolism), University of Tsukuba, Tsukuba 305–8575, Japan
- AMED-CREST, Tokyo, Japan
| | - Hiroaki Tokiwa
- Department of Chemistry, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
- Research Center for Smart molecules, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171–8501, Japan
- AMED-CREST, Tokyo, Japan
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21
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van Gunsteren WF, Allison JR, Daura X, Dolenc J, Hansen N, Mark AE, Oostenbrink C, Rusu VH, Smith LJ. Bestimmung von Strukturinformation aus experimentellen Messdaten für Biomoleküle. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601828] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Wilfred F. van Gunsteren
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Jane R. Allison
- Centre for Theor. Chem. and Phys. & Institute of Natural and Mathematical Sciences; Massey Univ.; Auckland Neuseeland
- Biomolecular Interaction Centre; University of Canterbury, Christchurch; Neuseeland
- Maurice Wilkins Centre for Molecular Biodiscovery; Neuseeland
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine; Universitat Autònoma de Barcelona (UAB); 08193 Barcelona Spanien
- Catalan Institution for Research and Advanced Studies (ICREA); 08010 Barcelona Spanien
| | - Jožica Dolenc
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Niels Hansen
- Institut für Technische Thermodynamik und Thermische Verfahrenstechnik; Universität Stuttgart; Pfaffenwaldring 9 70569 Stuttgart Deutschland
| | - Alan E. Mark
- School of Chemistry and Molecular Biosciences; University of Queensland; St. Lucia QLD 4072 Australien
| | - Chris Oostenbrink
- Institut für Molekulare Modellierung und Simulation; Universität für Bodenkultur Wien; Wien Österreich
| | - Victor H. Rusu
- Laboratorium für Physikalische Chemie; Eidgenössische Technische Hochschule Zürich; 8093 Zürich Schweiz
| | - Lorna J. Smith
- Department of Chemistry; University of Oxford, Inorganic Chemistry Laboratory; South Parks Road Oxford OX1 3QR Großbritannien
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22
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van Gunsteren WF, Allison JR, Daura X, Dolenc J, Hansen N, Mark AE, Oostenbrink C, Rusu VH, Smith LJ. Deriving Structural Information from Experimentally Measured Data on Biomolecules. Angew Chem Int Ed Engl 2016; 55:15990-16010. [PMID: 27862777 DOI: 10.1002/anie.201601828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 07/08/2016] [Indexed: 12/27/2022]
Abstract
During the past half century, the number and accuracy of experimental techniques that can deliver values of observables for biomolecular systems have been steadily increasing. The conversion of a measured value Qexp of an observable quantity Q into structural information is, however, a task beset with theoretical and practical problems: 1) insufficient or inaccurate values of Qexp , 2) inaccuracies in the function Q(r→) used to relate the quantity Q to structure r→ , 3) how to account for the averaging inherent in the measurement of Qexp , 4) how to handle the possible multiple-valuedness of the inverse r→(Q) of the function Q(r→) , to mention a few. These apply to a variety of observable quantities Q and measurement techniques such as X-ray and neutron diffraction, small-angle and wide-angle X-ray scattering, free-electron laser imaging, cryo-electron microscopy, nuclear magnetic resonance, electron paramagnetic resonance, infrared and Raman spectroscopy, circular dichroism, Förster resonance energy transfer, atomic force microscopy and ion-mobility mass spectrometry. The process of deriving structural information from measured data is reviewed with an eye to non-experts and newcomers in the field using examples from the literature of the effect of the various choices and approximations involved in the process. A list of choices to be avoided is provided.
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Affiliation(s)
- Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Jane R Allison
- Centre for Theor. Chem. and Phys. & Institute of Natural and Mathematical Sciences, Massey Univ., Auckland, New Zealand.,Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, New Zealand
| | - Xavier Daura
- Institute of Biotechnology and Biomedicine, Universitat Autònoma de Barcelona (UAB), 08193, Barcelona, Spain.,Catalan Institution for Research and Advanced Studies (ICREA), 08010, Barcelona, Spain
| | - Jožica Dolenc
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Niels Hansen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Pfaffenwaldring 9, 70569, Stuttgart, Germany
| | - Alan E Mark
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Victor H Rusu
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH, 8093, Zurich, Switzerland
| | - Lorna J Smith
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, UK
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23
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Hiruma Y, Koch A, Dharadhar S, Joosten RP, Perrakis A. Structural basis of reversine selectivity in inhibiting Mps1 more potently than aurora B kinase. Proteins 2016; 84:1761-1766. [PMID: 27699881 DOI: 10.1002/prot.25174] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/20/2016] [Accepted: 09/24/2016] [Indexed: 12/13/2022]
Abstract
Monopolar spindle 1 (Mps1, also known as TTK) is a protein kinase crucial for ensuring that cell division progresses to anaphase only after all chromosomes are connected to spindle microtubules. Incomplete chromosomal attachment leads to abnormal chromosome counts in the daughter cells (aneuploidy), a condition common in many solid cancers. Therefore Mps1 is an established target in cancer therapy. Mps1 kinase inhibitors include reversine (2-(4-morpholinoanilino)-6-cyclohexylaminopurine), a promiscuous compound first recognized as an inhibitor of the Aurora B mitotic kinase. Here, we present the 3.0-Å resolution crystal structure of the Mps1 kinase domain bound to reversine. Structural comparison of reversine bound to Mps1 and Aurora B, indicates a similar binding pose for the purine moiety of reversine making three conserved hydrogen bonds to the protein main chain, explaining the observed promiscuity of this inhibitor. The cyclohexyl and morpholinoaniline moieties of reversine however, have more extensive contacts with the protein in Mps1 than in Aurora B. This is reflected both in structure-based docking energy calculations, and in new experimental data we present here, that both confirm that the affinity of reversine towards Mps1 is about two orders of magnitude higher than towards Aurora B. Thus, our data provides detailed structural understanding of the existing literature that argues reversine inhibits Mps1 more efficiently than Aurora B based on biochemical and in-cell assays. Proteins 2016; 84:1761-1766. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yoshitaka Hiruma
- Division of Biochemistry, Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Andre Koch
- Division of Cell Biology, Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Shreya Dharadhar
- Division of Biochemistry, Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Robbie P Joosten
- Division of Biochemistry, Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
| | - Anastassis Perrakis
- Division of Biochemistry, Netherlands Cancer Institute, 1066CX, Amsterdam, The Netherlands
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24
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Touw WG, van Beusekom B, Evers JMG, Vriend G, Joosten RP. Validation and correction of Zn-Cys xHis y complexes. Acta Crystallogr D Struct Biol 2016; 72:1110-1118. [PMID: 27710932 PMCID: PMC5053137 DOI: 10.1107/s2059798316013036] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 08/12/2016] [Indexed: 11/10/2022] Open
Abstract
Many crystal structures in the Protein Data Bank contain zinc ions in a geometrically distorted tetrahedral complex with four Cys and/or His ligands. A method is presented to automatically validate and correct these zinc complexes. Analysis of the corrected zinc complexes shows that the average Zn-Cys distances and Cys-Zn-Cys angles are a function of the number of cysteines and histidines involved. The observed trends can be used to develop more context-sensitive targets for model validation and refinement.
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Affiliation(s)
- Wouter G. Touw
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Center, Geert Grooteplein-Zuid 26-28, 6525 GA Nijmegen, The Netherlands
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Bart van Beusekom
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Jochem M. G. Evers
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Center, Geert Grooteplein-Zuid 26-28, 6525 GA Nijmegen, The Netherlands
| | - Gert Vriend
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Center, Geert Grooteplein-Zuid 26-28, 6525 GA Nijmegen, The Netherlands
| | - Robbie P. Joosten
- Department of Biochemistry, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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25
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Determining crystal structures through crowdsourcing and coursework. Nat Commun 2016; 7:12549. [PMID: 27633552 PMCID: PMC5028414 DOI: 10.1038/ncomms12549] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/12/2016] [Indexed: 01/22/2023] Open
Abstract
We show here that computer game players can build high-quality crystal structures. Introduction of a new feature into the computer game Foldit allows players to build and real-space refine structures into electron density maps. To assess the usefulness of this feature, we held a crystallographic model-building competition between trained crystallographers, undergraduate students, Foldit players and automatic model-building algorithms. After removal of disordered residues, a team of Foldit players achieved the most accurate structure. Analysing the target protein of the competition, YPL067C, uncovered a new family of histidine triad proteins apparently involved in the prevention of amyloid toxicity. From this study, we conclude that crystallographers can utilize crowdsourcing to interpret electron density information and to produce structure solutions of the highest quality. Building crystal structures into the electron density is an important step in protein structure solution. Here, the authors recruit online game players, students, and experienced crystallographers to compete in a competition to solve a new structure, and find that crowdsourcing model-building works.
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26
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Kumar A, Balakrishna AM, Nartey W, Manimekalai MSS, Grüber G. Redox chemistry of Mycobacterium tuberculosis alkylhydroperoxide reductase E (AhpE): Structural and mechanistic insight into a mycoredoxin-1 independent reductive pathway of AhpE via mycothiol. Free Radic Biol Med 2016; 97:588-601. [PMID: 27417938 DOI: 10.1016/j.freeradbiomed.2016.07.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 11/28/2022]
Abstract
Mycobacterium tuberculosis (Mtb) has the ability to persist within the human host for a long time in a dormant stage and re-merges when the immune system is compromised. The pathogenic bacterium employs an elaborate antioxidant defence machinery composed of the mycothiol- and thioredoxin system in addition to a superoxide dismutase, a catalase, and peroxiredoxins (Prxs). Among the family of Peroxiredoxins, Mtb expresses a 1-cysteine peroxiredoxin, known as alkylhydroperoxide reductase E (MtAhpE), and defined as a potential tuberculosis drug target. The reduced MtAhpE (MtAhpE-SH) scavenges peroxides to become converted to MtAhpE-SOH. To provide continuous availability of MtAhpE-SH, MtAhpE-SOH has to become reduced. Here, we used NMR spectroscopy to delineate the reduced (MtAhpE-SH), sulphenic (MtAhpE-SOH) and sulphinic (MtAhpE-SO2H) states of MtAhpE through cysteinyl-labelling, and provide for the first time evidence of a mycothiol-dependent mechanism of MtAhpE reduction. This is confirmed by crystallographic studies, wherein MtAhpE was crystallized in the presence of mycothiol and the structure was solved at 2.43Å resolution. Combined with NMR-studies, the crystallographic structures reveal conformational changes of important residues during the catalytic cycle of MtAhpE. In addition, alterations of the overall protein in solution due to redox modulation are observed by small angle X-ray scattering (SAXS) studies. Finally, by employing SAXS and dynamic light scattering, insight is provided into the most probable physiological oligomeric state of MtAhpE necessary for activity, being also discussed in the context of concerted substrate binding inside the dimeric MtAhpE.
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Affiliation(s)
- Arvind Kumar
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
| | - Asha Manikkoth Balakrishna
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
| | - Wilson Nartey
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore
| | | | - Gerhard Grüber
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
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