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Holdgate GA, Meek TD, Grimley RL. Mechanistic enzymology in drug discovery: a fresh perspective. Nat Rev Drug Discov 2017; 17:115-132. [PMID: 29192286 DOI: 10.1038/nrd.2017.219] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Given the therapeutic and commercial success of small-molecule enzyme inhibitors, as exemplified by kinase inhibitors in oncology, a major focus of current drug-discovery and development efforts is on enzyme targets. Understanding the course of an enzyme-catalysed reaction can help to conceptualize different types of inhibitor and to inform the design of screens to identify desired mechanisms. Exploiting this information allows the thorough evaluation of diverse compounds, providing the knowledge required to efficiently optimize leads towards differentiated candidate drugs. This review highlights the rationale for conducting high-quality mechanistic enzymology studies and considers the added value in combining such studies with orthogonal biophysical methods.
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Affiliation(s)
- Geoffrey A Holdgate
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Building 310, Cambridge Science Park, Milton Road, Cambridge, CB4 0WG, UK
| | - Thomas D Meek
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, Texas 77843, USA
| | - Rachel L Grimley
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Building 310, Cambridge Science Park, Milton Road, Cambridge, CB4 0WG, UK
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Sánchez-Lombardo I, Alvarez S, McLauchlan CC, Crans DC. Evaluating transition state structures of vanadium-phosphatase protein complexes using shape analysis. J Inorg Biochem 2015; 147:153-64. [PMID: 25953100 DOI: 10.1016/j.jinorgbio.2015.04.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 04/08/2015] [Accepted: 04/08/2015] [Indexed: 12/19/2022]
Abstract
Shape analysis of coordination complexes is well-suited to evaluate the subtle distortions in the trigonal bipyramidal (TBPY-5) geometry of vanadium coordinated in the active site of phosphatases and characterized by X-ray crystallography. Recent studies using the tau (τ) analysis support the assertion that vanadium is best described as a trigonal bipyramid, because this geometry is the ideal transition state geometry of the phosphate ester substrate hydrolysis (C.C. McLauchlan, B.J. Peters, G.R. Willsky, D.C. Crans, Coord. Chem. Rev. http://dx.doi.org/10.1016/j.ccr.2014.12.012 ; D.C. Crans, M.L. Tarlton, C.C. McLauchlan, Eur. J. Inorg. Chem. 2014, 4450-4468). Here we use continuous shape measures (CShM) analysis to investigate the structural space of the five-coordinate vanadium-phosphatase complexes associated with mechanistic transformations between the tetrahedral geometry and the five-coordinate high energy TBPY-5 geometry was discussed focusing on the protein tyrosine phosphatase 1B (PTP1B) enzyme. No evidence for square pyramidal geometries was observed in any vanadium-protein complexes. The shape analysis positioned the metal ion and the ligands in the active site reflecting the mechanism of the cleavage of the organic phosphate in a phosphatase. We identified the umbrella distortions to be directly on the reaction path between tetrahedral phosphate and the TBPY-5-types of high-energy species. The umbrella distortions of the trigonal bipyramid are therefore identified as being the most relevant types of transition state structures for the phosphoryl group transfer reactions for phosphatases and this may be related to the possibility that vanadium is an inhibitor for enzymes that support both exploded and five-coordinate transition states.
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Affiliation(s)
| | - Santiago Alvarez
- Departament de Química Inorganica, Institut de Química Teorica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franques, 1-11, 08028 Barcelona, Spain.
| | - Craig C McLauchlan
- Department of Chemistry, Illinois State University, Campus Box 4160, Normal, IL 61790, USA
| | - Debbie C Crans
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
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Herzog FA, Vogel V. Multiple steps to activate FAK's kinase domain: adaptation to confined environments? Biophys J 2014; 104:2521-9. [PMID: 23746525 DOI: 10.1016/j.bpj.2013.04.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 03/27/2013] [Accepted: 04/05/2013] [Indexed: 10/26/2022] Open
Abstract
Protein kinases regulate cell signaling by phosphorylating their substrates in response to environment-specific stimuli. Using molecular dynamics, we studied the catalytically active and inactive conformations of the kinase domain of the focal adhesion kinase (FAK), which are distinguished by displaying a structured or unstructured activation loop, respectively. Upon removal of an ATP analog, we show that the nucleotide-binding pocket in the catalytically active conformation is structurally unstable and fluctuates between an open and closed configuration. In contrast, the pocket remains open in the catalytically inactive form upon removal of an inhibitor from the pocket. Because temporal pocket closures will slow the ATP on-rate, these simulations suggest a multistep process in which the kinase domain is more likely to bind ATP in the catalytically inactive than in the active form. Transient closures of the ATP-binding pocket might allow FAK to slow down its catalytic cycle. These short cat naps could be adaptions to crowded or confined environments by giving the substrate sufficient time to diffuse away. The simulations show further how either the phosphorylation of the activation loop or the activating mutations of the so-called SuperFAK influence the electrostatic switch that controls kinase activity.
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Affiliation(s)
- Florian A Herzog
- Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
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Nicolini P, Frezzato D, Gellini C, Bizzarri M, Chelli R. Toward quantitative estimates of binding affinities for protein-ligand systems involving large inhibitor compounds: a steered molecular dynamics simulation route. J Comput Chem 2013; 34:1561-76. [PMID: 23620471 DOI: 10.1002/jcc.23286] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/01/2013] [Accepted: 03/05/2013] [Indexed: 11/09/2022]
Abstract
Understanding binding mechanisms between enzymes and potential inhibitors and quantifying protein-ligand affinities in terms of binding free energy is of primary importance in drug design studies. In this respect, several approaches based on molecular dynamics simulations, often combined with docking techniques, have been exploited to investigate the physicochemical properties of complexes of pharmaceutical interest. Even if the geometric properties of a modeled protein-ligand complex can be well predicted by computational methods, it is still challenging to rank with chemical accuracy a series of ligand analogues in a consistent way. In this article, we face this issue calculating relative binding free energies of a focal adhesion kinase, an important target for the development of anticancer drugs, with pyrrolopyrimidine-based ligands having different inhibitory power. To this aim, we employ steered molecular dynamics simulations combined with nonequilibrium work theorems for free energy calculations. This technique proves very powerful when a series of ligand analogues is considered, allowing one to tackle estimation of protein-ligand relative binding free energies in a reasonable time. In our cases, the calculated binding affinities are comparable with those recovered from experiments by exploiting the Michaelis-Menten mechanism with a competitive inhibitor.
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Affiliation(s)
- Paolo Nicolini
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Campus Nord B4-B5, E-08034 Barcelona, Spain
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Summerton JC, Evanseck JD, Chapman MS. Hyperconjugation-mediated solvent effects in phosphoanhydride bonds. J Phys Chem A 2012; 116:10209-17. [PMID: 23009395 DOI: 10.1021/jp306607k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional theory and natural bond orbital analysis are used to explore the impact of solvent on hyperconjugation in methyl triphosphate, a model for "energy rich" phosphoanhydride bonds, such as found in ATP. As expected, dihedral rotation of a hydroxyl group vicinal to the phosphoanhydride bond reveals that the conformational dependence of the anomeric effect involves modulation of the orbital overlap between the donor and acceptor orbitals. However, a conformational independence was observed in the rotation of a solvent hydrogen bond. As one lone pair orbital rotates away from an optimal antiperiplanar orientation, the overall magnitude of the anomeric effect is compensated approximately by the other lone pair as it becomes more antiperiplanar. Furthermore, solvent modulation of the anomeric effect is not restricted to the antiperiplanar lone pair; hydrogen bonds involving gauche lone pairs also affect the anomeric interaction and the strength of the phosphoanhydride bond. Both gauche and anti solvent hydrogen bonds lengthen nonbridging O-P bonds, increasing the distance between donor and acceptor orbitals and decreasing orbital overlap, which leads to a reduction of the anomeric effect. Solvent effects are additive with greater reduction in the anomeric effect upon increasing water coordination. By controlling the coordination environment of substrates in an active site, kinases, phosphatases, and other enzymes important in metabolism and signaling may have the potential to modulate the stability of individual phosphoanhydride bonds through stereoelectronic effects.
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Affiliation(s)
- Jean C Summerton
- Department of Biochemistry & Molecular Biology, School of Medicine, Oregon Health & Science University, Mail Code L224, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239-3098, USA
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Fan F, Williams HJ, Boyer JG, Graham TL, Zhao H, Lehr R, Qi H, Schwartz B, Raushel FM, Meek TD. On the catalytic mechanism of human ATP citrate lyase. Biochemistry 2012; 51:5198-211. [PMID: 22657152 DOI: 10.1021/bi300611s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ATP citrate lyase (ACL) catalyzes an ATP-dependent biosynthetic reaction which produces acetyl-coenzyme A and oxaloacetate from citrate and coenzyme A (CoA). Studies were performed with recombinant human ACL to ascertain the nature of the catalytic phosphorylation that initiates the ACL reaction and the identity of the active site residues involved. Inactivation of ACL by treatment with diethylpyrocarbonate suggested the catalytic role of an active site histidine (i.e., His760), which was proposed to form a phosphohistidine species during catalysis. The pH-dependence of the pre-steady-state phosphorylation of ACL with [γ-(33)P]-ATP revealed an ionizable group with a pK(a) value of ~7.5, which must be unprotonated for the catalytic phosphorylation of ACL to occur. Mutagenesis of His760 to an alanine results in inactivation of the biosynthetic reaction of ACL, in good agreement with the involvement of a catalytic histidine. The nature of the formation of the phospho-ACL was further investigated by positional isotope exchange using [γ-(18)O(4)]-ATP. The β,γ-bridge to nonbridge positional isotope exchange rate of [γ-(18)O(4)]-ATP achieved its maximal rate of 14 s(-1) in the absence of citrate and CoA. This rate decreased to 5 s(-1) when citrate was added, and was found to be 10 s(-1) when both citrate and CoA were present. The rapid positional isotope exchange rates indicated the presence of one or more catalytically relevant, highly reversible phosphorylated intermediates. Steady-state measurements in the absence of citrate and CoA showed that MgADP was produced by both wild type and H760A forms of ACL, with rates at three magnitudes lower than that of k(cat) for the full biosynthetic reaction. The ATPase activity of ACL, along with the small yet significant positional isotope exchange rate observed in H760A mutant ACL (~150 fold less than wild type), collectively suggested the presence of a second, albeit unproductive, phosphoryl transfer in ACL. Mathematical analysis and computational simulation suggested that the desorption of MgADP at a rate of ~7 s(-1) was the rate-limiting step in the biosynthesis of AcCoA and oxaloacetate.
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Affiliation(s)
- Fan Fan
- Biological Reagents and Assay Development, GlaxoSmithKline, Collegeville, Pennsylvania 19426, USA.
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Huang X, Hernick M. Examination of mechanism of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) reveals unexpected role for dynamic tyrosine. J Biol Chem 2012; 287:10424-10434. [PMID: 22315231 DOI: 10.1074/jbc.m111.320184] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actinomycetes are a group of gram-positive bacteria that includes pathogenic mycobacterial species, such as Mycobacterium tuberculosis. These organisms do not have glutathione and instead utilize the small molecule mycothiol (MSH) as their primary reducing agent and for the detoxification of xenobiotics. Due to these important functions, enzymes involved in MSH biosynthesis and MSH-dependent detoxification are targets for drug development. The metal-dependent deacetylase N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) catalyzes the hydrolysis of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside to form 1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside and acetate in MSH biosynthesis. Herein we examine the chemical mechanism of MshB. We demonstrate that the side chains of Asp-15, Tyr-142, His-144, and Asp-146 are important for catalytic activity. We show that NaF is an uncompetitive inhibitor of MshB, consistent with a metal-water/hydroxide functioning as the reactive nucleophile in the catalytic mechanism. We have previously shown that MshB activity has a bell-shaped dependence on pH with pK(a) values of ∼7.3 and 10.5 (Huang, X., Kocabas, E. and Hernick, M. (2011) J. Biol. Chem. 286, 20275-20282). Mutagenesis experiments indicate that the observed pK(a) values reflect ionization of Asp-15 and Tyr-142, respectively. Together, findings from our studies suggest that MshB functions through a general acid-base pair mechanism with the side chain of Asp-15 functioning as the general base catalyst and His-144 serving as the general acid catalyst, whereas the side chain of Tyr-142 probably assists in polarizing substrate/stabilizing the oxyanion intermediate. Additionally, our results indicate that Tyr-142 is a dynamic side chain that plays key roles in catalysis, modulating substrate binding, chemistry, and product release.
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Affiliation(s)
- Xinyi Huang
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
| | - Marcy Hernick
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061.
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Schwartz PA, Murray BW. Protein kinase biochemistry and drug discovery. Bioorg Chem 2011; 39:192-210. [PMID: 21872901 DOI: 10.1016/j.bioorg.2011.07.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 12/19/2022]
Abstract
Protein kinases are fascinating biological catalysts with a rapidly expanding knowledge base, a growing appreciation in cell regulatory control, and an ascendant role in successful therapeutic intervention. To better understand protein kinases, the molecular underpinnings of phosphoryl group transfer, protein phosphorylation, and inhibitor interactions are examined. This analysis begins with a survey of phosphate group and phosphoprotein properties which provide context to the evolutionary selection of phosphorylation as a central mechanism for biological regulation of most cellular processes. Next, the kinetic and catalytic mechanisms of protein kinases are examined with respect to model aqueous systems to define the elements of catalysis. A brief structural biology overview further delves into the molecular basis of catalysis and regulation of catalytic activity. Concomitant with a prominent role in normal physiology, protein kinases have important roles in the disease state. To facilitate effective kinase drug discovery, classic and emerging approaches for characterizing kinase inhibitors are evaluated including biochemical assay design, inhibitor mechanism of action analysis, and proper kinetic treatment of irreversible inhibitors. As the resulting protein kinase inhibitors can modulate intended and unintended targets, profiling methods are discussed which can illuminate a more complete range of an inhibitor's biological activities to enable more meaningful cellular studies and more effective clinical studies. Taken as a whole, a wealth of protein kinase biochemistry knowledge is available, yet it is clear that a substantial extent of our understanding in this field remains to be discovered which should yield many new opportunities for therapeutic intervention.
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Affiliation(s)
- Phillip A Schwartz
- Pfizer Worldwide Research and Development, La Jolla, Pfizer Inc., San Diego, CA 92121, United States
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Juranić N, Nemutlu E, Zhang S, Dzeja P, Terzic A, Macura S. (31)P NMR correlation maps of (18)O/ (16)O chemical shift isotopic effects for phosphometabolite labeling studies. JOURNAL OF BIOMOLECULAR NMR 2011; 50:237-245. [PMID: 21611840 PMCID: PMC3230932 DOI: 10.1007/s10858-011-9515-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 05/06/2011] [Indexed: 05/30/2023]
Abstract
Intramolecular correlations among the (18)O-labels of metabolic oligophosphates, mapped by J-decoupled (31)P NMR 2D chemical shift correlation spectroscopy, impart stringent constraints to the (18)O-isotope distributions over the whole oligophosphate moiety. The multiple deduced correlations of isotopic labels enable determination of site-specific fractional isotope enrichments and unravel the isotopologue statistics. This approach ensures accurate determination of (18)O-labeling rates of phosphometabolites, critical in biochemical energy conversion and metabolic flux transmission. The biological usefulness of the J-decoupled (31)P NMR 2D chemical shift correlation maps was validated on adenosine tri-phosphate fractionally (18)O labeled in perfused mammalian hearts.
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Affiliation(s)
- Nenad Juranić
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905, USA.
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