1
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Johnson CW, Fetics SK, Davis KP, Rodrigues JA, Mattos C. Allosteric site variants affect GTP hydrolysis on Ras. Protein Sci 2023; 32:e4767. [PMID: 37615343 PMCID: PMC10510474 DOI: 10.1002/pro.4767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/03/2023] [Accepted: 08/21/2023] [Indexed: 08/25/2023]
Abstract
RAS GTPases are proto-oncoproteins that regulate cell growth, proliferation, and differentiation in response to extracellular signals. The signaling functions of RAS, and other small GTPases, are dependent on their ability to cycle between GDP-bound and GTP-bound states. Structural analyses suggest that GTP hydrolysis catalyzed by HRAS can be regulated by an allosteric site located between helices 3, 4, and loop 7. Here we explore the relationship between intrinsic GTP hydrolysis on HRAS and the position of helix 3 and loop 7 through manipulation of the allosteric site, showing that the two sites are functionally connected. We generated several hydrophobic mutations in the allosteric site of HRAS to promote shifts in helix 3 relative to helix 4. By combining crystallography and enzymology to study these mutants, we show that closure of the allosteric site correlates with increased hydrolysis of GTP on HRAS in solution. Interestingly, binding to the RAS binding domain of RAF kinase (RAF-RBD) inhibits GTP hydrolysis in the mutants. This behavior may be representative of a cluster of mutations found in human tumors, which potentially cooperate with RAF complex formation to stabilize the GTP-bound state of RAS.
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Affiliation(s)
- Christian W. Johnson
- Department of Chemistry and Chemical BiologyNortheastern UniversityBostonMassachusettsUSA
| | - Susan K. Fetics
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Kathleen P. Davis
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Jose A. Rodrigues
- Department of Chemistry and Chemical BiologyNortheastern UniversityBostonMassachusettsUSA
| | - Carla Mattos
- Department of Chemistry and Chemical BiologyNortheastern UniversityBostonMassachusettsUSA
- Department of Molecular and Structural BiochemistryNorth Carolina State UniversityRaleighNorth CarolinaUSA
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2
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Volmar AY, Guterres H, Zhou H, Reid D, Pavlopoulos S, Makowski L, Mattos C. Mechanisms of isoform-specific residue influence on GTP-bound HRas, KRas, and NRas. Biophys J 2022; 121:3616-3629. [PMID: 35794829 PMCID: PMC9617160 DOI: 10.1016/j.bpj.2022.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/04/2022] [Accepted: 07/01/2022] [Indexed: 11/16/2022] Open
Abstract
HRas, KRas, and NRas are GTPases with a common set of effectors that control many cell-signaling pathways, including proliferation through Raf kinase. Their G-domains are nearly identical in sequence, with a few isoform-specific residues that have an effect on dynamics and biochemical properties. Here, we use accelerated molecular dynamics (aMD) simulations consistent with solution x-ray scattering experiments to elucidate mechanisms through which isoform-specific residues associated with each Ras isoform affects functionally important regions connected to the active site. HRas-specific residues cluster in loop 8 to stabilize the nucleotide-binding pocket, while NRas-specific residues on helix 3 directly affect the conformations of switch I and switch II. KRas, the most globally flexible of the isoforms, shows greatest fluctuations in the switch regions enhanced by a KRas-specific residue in loop 7 and a highly dynamic loop 8 region. The analysis of isoform-specific residue effects on Ras proteins is supported by NMR experiments and is consistent with previously published biochemical data.
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Affiliation(s)
- Alicia Y Volmar
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Hugo Guterres
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Hao Zhou
- Department of Electrical and Computing Engineering, Northeastern University, Boston, Massachusetts
| | - Derion Reid
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Spiro Pavlopoulos
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts
| | - Lee Makowski
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts; Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.
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3
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Ras Isoforms from Lab Benches to Lives-What Are We Missing and How Far Are We? Int J Mol Sci 2021; 22:ijms22126508. [PMID: 34204435 PMCID: PMC8233758 DOI: 10.3390/ijms22126508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/21/2022] Open
Abstract
The central protein in the oncogenic circuitry is the Ras GTPase that has been under intense scrutiny for the last four decades. From its discovery as a viral oncogene and its non-oncogenic contribution to crucial cellular functioning, an elaborate genetic, structural, and functional map of Ras is being created for its therapeutic targeting. Despite decades of research, there still exist lacunae in our understanding of Ras. The complexity of the Ras functioning is further exemplified by the fact that the three canonical Ras genes encode for four protein isoforms (H-Ras, K-Ras4A, K-Ras4B, and N-Ras). Contrary to the initial assessment that the H-, K-, and N-Ras isoforms are functionally similar, emerging data are uncovering crucial differences between them. These Ras isoforms exhibit not only cell-type and context-dependent functions but also activator and effector specificities on activation by the same receptor. Preferential localization of H-, K-, and N-Ras in different microdomains of the plasma membrane and cellular organelles like Golgi, endoplasmic reticulum, mitochondria, and endosome adds a new dimension to isoform-specific signaling and diverse functions. Herein, we review isoform-specific properties of Ras GTPase and highlight the importance of considering these towards generating effective isoform-specific therapies in the future.
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4
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Rudack T, Teuber C, Scherlo M, Güldenhaupt J, Schartner J, Lübben M, Klare J, Gerwert K, Kötting C. The Ras dimer structure. Chem Sci 2021; 12:8178-8189. [PMID: 34194708 PMCID: PMC8208300 DOI: 10.1039/d1sc00957e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/29/2021] [Indexed: 12/31/2022] Open
Abstract
Oncogenic mutated Ras is a key player in cancer, but despite intense and expensive approaches its catalytic center seems undruggable. The Ras dimer interface is a possible alternative drug target. Dimerization at the membrane affects cell growth signal transduction. In vivo studies indicate that preventing dimerization of oncogenic mutated Ras inhibits uncontrolled cell growth. Conventional computational drug-screening approaches require a precise atomic dimer model as input to successfully access drug candidates. However, the proposed dimer structural models are controversial. Here, we provide a clear-cut experimentally validated N-Ras dimer structural model. We incorporated unnatural amino acids into Ras to enable the binding of labels at multiple positions via click chemistry. This labeling allowed the determination of multiple distances of the membrane-bound Ras-dimer measured by fluorescence and electron paramagnetic resonance spectroscopy. In combination with protein-protein docking and biomolecular simulations, we identified key residues for dimerization. Site-directed mutations of these residues prevent dimer formation in our experiments, proving our dimer model to be correct. The presented dimer structure enables computational drug-screening studies exploiting the Ras dimer interface as an alternative drug target.
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Affiliation(s)
- Till Rudack
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Christian Teuber
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Marvin Scherlo
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Jörn Güldenhaupt
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Jonas Schartner
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Mathias Lübben
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Johann Klare
- Department of Physics, Osnabrück University 49074 Osnabrück Germany
| | - Klaus Gerwert
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
| | - Carsten Kötting
- Biospectroscopy, Center for Protein Diagnostics (PRODI), Ruhr University Bochum 44801 Bochum Germany
- Department of Biophysics, Ruhr University Bochum 44801 Bochum Germany
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5
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Agarwal S, Smith M, De La Rosa I, Verba KA, Swartz P, Segura-Totten M, Mattos C. Development of a structure-analysis pipeline using multiple-solvent crystal structures of barrier-to-autointegration factor. Acta Crystallogr D Struct Biol 2020; 76:1001-1014. [DOI: 10.1107/s2059798320011341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/18/2020] [Indexed: 11/10/2022] Open
Abstract
The multiple-solvent crystal structure (MSCS) approach uses high concentrations of organic solvents to characterize the interactions and effects of solvents on proteins. Here, the method has been further developed and an MSCS data-handling pipeline is presented that uses the Detection of Related Solvent Positions (DRoP) program to improve data quality. DRoP is used to selectively model conserved water molecules, so that an advanced stage of structural refinement is reached quickly. This allows the placement of organic molecules more accurately and convergence on high-quality maps and structures. This pipeline was applied to the chromatin-associated protein barrier-to-autointegration factor (BAF), resulting in structural models with better than average statistics. DRoP and Phenix Structure Comparison were used to characterize the data sets and to identify a binding site that overlaps with the interaction site of BAF with emerin. The conserved water-mediated networks identified by DRoP suggested a mechanism by which water molecules are used to drive the binding of DNA. Normalized and differential B-factor analysis is shown to be a valuable tool to characterize the effects of specific solvents on defined regions of BAF. Specific solvents are identified that cause stabilization of functionally important regions of the protein. This work presents tools and a standardized approach for the analysis and comprehension of MSCS data sets.
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6
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How to make an undruggable enzyme druggable: lessons from ras proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020. [PMID: 32951811 DOI: 10.1016/bs.apcsb.2020.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
Significant advances have been made toward discovering allosteric inhibitors for challenging drug targets such as the Ras family of membrane-associated signaling proteins. Malfunction of Ras proteins due to somatic mutations is associated with up to a quarter of all human cancers. Computational techniques have played critical roles in identifying and characterizing allosteric ligand-binding sites on these proteins, and to screen ligand libraries against those sites. These efforts, combined with a wide range of biophysical, structural, biochemical and cell biological experiments, are beginning to yield promising inhibitors to treat malignancies associated with mutated Ras proteins. In this chapter, we discuss some of these developments and how the lessons learned from Ras might be applied to similar other challenging drug targets.
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7
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Johnson CW, Lin YJ, Reid D, Parker J, Pavlopoulos S, Dischinger P, Graveel C, Aguirre AJ, Steensma M, Haigis KM, Mattos C. Isoform-Specific Destabilization of the Active Site Reveals a Molecular Mechanism of Intrinsic Activation of KRas G13D. Cell Rep 2020; 28:1538-1550.e7. [PMID: 31390567 PMCID: PMC6709685 DOI: 10.1016/j.celrep.2019.07.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/28/2019] [Accepted: 07/10/2019] [Indexed: 12/21/2022] Open
Abstract
Ras GTPases are mutated at codons 12, 13, and 61, with different frequencies in KRas, HRas, and NRas and in a cancer-specific manner. The G13D mutant appears in 25% of KRas-driven colorectal cancers, while observed only rarely in HRas or NRas. Structures of Ras G13D in the three isoforms show an open active site, with adjustments to the D13 backbone torsion angles and with disconnected switch regions. KRas G13D has unique features that destabilize the nucleotide-binding pocket. In KRas G13D bound to GDP, A59 is placed in the Mg2+ binding site, as in the HRas-SOS complex. Structure and biochemistry are consistent with an intermediate level of KRas G13D bound to GTP, relative to wild-type and KRas G12D, observed in genetically engineered mouse models. The results explain in part the elevated frequency of the G13D mutant in KRas over the other isoforms of Ras.
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Affiliation(s)
- Christian W Johnson
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Yi-Jang Lin
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Derion Reid
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Jillian Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Spiro Pavlopoulos
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | | | - Carrie Graveel
- Van Andel Research Institute, Grand Rapids, MI 49503, USA
| | - Andrew J Aguirre
- Dana-Farber Cancer Institute, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Kevin M Haigis
- Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02215, USA; Harvard Digestive Disease Center, Boston, MA 02215, USA.
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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8
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Marcus K, Mattos C. Water in Ras Superfamily Evolution. J Comput Chem 2020; 41:402-414. [PMID: 31483874 DOI: 10.1002/jcc.26060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/17/2019] [Accepted: 08/16/2019] [Indexed: 01/14/2023]
Abstract
The Ras GTPase superfamily of proteins coordinates a diverse set of cellular outcomes, including cell morphology, vesicle transport, and cell proliferation. Primary amino acid sequence analysis has identified Specificity determinant positions (SDPs) that drive diversified functions specific to the Ras, Rho, Rab, and Arf subfamilies (Rojas et al. 2012, J Cell Biol 196:189-201). The inclusion of water molecules in structural and functional adaptation is likely to be a major response to the selection pressures that drive evolution, yet hydration patterns are not included in phylogenetic analysis. This article shows that conserved crystallographic water molecules coevolved with SDP residues in the differentiation of proteins within the Ras superfamily of small GTPases. The patterns of water conservation between protein subfamilies parallel those of sequence-based evolutionary trees. Thus, hydration patterns have the potential to help elucidate functional significance in the evolution of amino acid residues observed in phylogenetic analysis of homologous proteins. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Kendra Marcus
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Ave, Boston, Massachusetts, 02115
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Ave, Boston, Massachusetts, 02115
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9
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Zhong M, Lynch A, Muellers SN, Jehle S, Luo L, Hall DR, Iwase R, Carolan JP, Egbert M, Wakefield A, Streu K, Harvey CM, Ortet PC, Kozakov D, Vajda S, Allen KN, Whitty A. Interaction Energetics and Druggability of the Protein-Protein Interaction between Kelch-like ECH-Associated Protein 1 (KEAP1) and Nuclear Factor Erythroid 2 Like 2 (Nrf2). Biochemistry 2020; 59:563-581. [PMID: 31851823 PMCID: PMC8177486 DOI: 10.1021/acs.biochem.9b00943] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Development of small molecule inhibitors of protein-protein interactions (PPIs) is hampered by our poor understanding of the druggability of PPI target sites. Here, we describe the combined application of alanine-scanning mutagenesis, fragment screening, and FTMap computational hot spot mapping to evaluate the energetics and druggability of the highly charged PPI interface between Kelch-like ECH-associated protein 1 (KEAP1) and nuclear factor erythroid 2 like 2 (Nrf2), an important drug target. FTMap identifies four binding energy hot spots at the active site. Only two of these are exploited by Nrf2, which alanine scanning of both proteins shows to bind primarily through E79 and E82 interacting with KEAP1 residues S363, R380, R415, R483, and S508. We identify fragment hits and obtain X-ray complex structures for three fragments via crystal soaking using a new crystal form of KEAP1. Combining these results provides a comprehensive and quantitative picture of the origins of binding energy at the interface. Our findings additionally reveal non-native interactions that might be exploited in the design of uncharged synthetic ligands to occupy the same site on KEAP1 that has evolved to bind the highly charged DEETGE binding loop of Nrf2. These include π-stacking with KEAP1 Y525 and interactions at an FTMap-identified hot spot deep in the binding site. Finally, we discuss how the complementary information provided by alanine-scanning mutagenesis, fragment screening, and computational hot spot mapping can be integrated to more comprehensively evaluate PPI druggability.
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Affiliation(s)
| | | | | | | | | | - David R Hall
- Acpharis, Inc. , 160 North Mill Street , Holliston , Massachusetts 01746 , United States
| | | | | | | | | | | | | | | | - Dima Kozakov
- Department of Applied Mathematics , Stony Brook University , Stony Brook , New York 11794 , United States
| | - Sandor Vajda
- Biomolecular Engineering Research Center , Boston University , Boston , Massachusetts 02215 , United States
| | - Karen N Allen
- Biomolecular Engineering Research Center , Boston University , Boston , Massachusetts 02215 , United States
| | - Adrian Whitty
- Biomolecular Engineering Research Center , Boston University , Boston , Massachusetts 02215 , United States
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10
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Khaled M, Gorfe A, Sayyed-Ahmad A. Conformational and Dynamical Effects of Tyr32 Phosphorylation in K-Ras: Molecular Dynamics Simulation and Markov State Models Analysis. J Phys Chem B 2019; 123:7667-7675. [PMID: 31419909 PMCID: PMC7020251 DOI: 10.1021/acs.jpcb.9b05768] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phosphorylation of tyrosine 32 in K-Ras has been shown to influence function by disrupting the GTPase cycle. To shed light on the underlying mechanism and atomic basis of this process, we carried out a comparative investigation of the oncogenic G12D K-Ras mutant and its phosphorylated variant (pTyr32) using all-atom molecular dynamics simulations and Markov state models. We show that, despite sharing a number of common features, G12D and pTyr32-G12D K-Ras exhibit some distinct conformational states and fluctuations. In addition to notable differences in conformation and dynamics of residues surrounding the GTP binding site, nonlocal changes were observed at a number of loops. Switch I is more flexible in pTyr32-G12D K-Ras while switch II is more flexible in G12D K-Ras. We also used time-lagged independent component analysis and k-means clustering to identify five metastable states for each system. We utilized transition path theory to calculate the transition probabilities for each state to build a Markov state model for each system. These models and other close inspections suggest that the phosphorylation of Tyr32 strongly affects protein dynamics and the active site conformation, especially with regards to the canonical switch conformations and dynamics.
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Affiliation(s)
- Mohammed Khaled
- Department of Physics, Birzeit University, PO Box 14, Birzeit, Palestine
| | - Alemayehu Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, 6431 Fannin Street, Houston, Texas 77030, United States
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11
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Oncogenic G12D mutation alters local conformations and dynamics of K-Ras. Sci Rep 2019; 9:11730. [PMID: 31409810 PMCID: PMC6692342 DOI: 10.1038/s41598-019-48029-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 07/29/2019] [Indexed: 12/19/2022] Open
Abstract
K-Ras is the most frequently mutated oncoprotein in human cancers, and G12D is its most prevalent mutation. To understand how G12D mutation impacts K-Ras function, we need to understand how it alters the regulation of its dynamics. Here, we present local changes in K-Ras structure, conformation and dynamics upon G12D mutation, from long-timescale Molecular Dynamics simulations of active (GTP-bound) and inactive (GDP-bound) forms of wild-type and mutant K-Ras, with an integrated investigation of atomistic-level changes, local conformational shifts and correlated residue motions. Our results reveal that the local changes in K-Ras are specific to bound nucleotide (GTP or GDP), and we provide a structural basis for this. Specifically, we show that G12D mutation causes a shift in the population of local conformational states of K-Ras, especially in Switch-II (SII) and α3-helix regions, in favor of a conformation that is associated with a catalytically impaired state through structural changes; it also causes SII motions to anti-correlate with other regions. This detailed picture of G12D mutation effects on the local dynamic characteristics of both active and inactive protein helps enhance our understanding of local K-Ras dynamics, and can inform studies on the development of direct inhibitors towards the treatment of K-RasG12D-driven cancers.
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12
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Kearney BM, Schwabe M, Marcus KC, Roberts DM, Dechene M, Swartz P, Mattos C. DRoP: Automated detection of conserved solvent-binding sites on proteins. Proteins 2019; 88:152-165. [PMID: 31294888 DOI: 10.1002/prot.25781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 06/19/2019] [Accepted: 07/06/2019] [Indexed: 11/08/2022]
Abstract
Water and ligand binding play critical roles in the structure and function of proteins, yet their binding sites and significance are difficult to predict a priori. Multiple solvent crystal structures (MSCS) is a method where several X-ray crystal structures are solved, each in a unique solvent environment, with organic molecules that serve as probes of the protein surface for sites evolved to bind ligands, while the first hydration shell is essentially maintained. When superimposed, these structures contain a vast amount of information regarding hot spots of protein-protein or protein-ligand interactions, as well as conserved water-binding sites retained with the change in solvent properties. Optimized mining of this information requires reliable structural data and a consistent, objective analysis tool. Detection of related solvent positions (DRoP) was developed to automatically organize and rank the water or small organic molecule binding sites within a given set of structures. It is a flexible tool that can also be used in conserved water analysis given multiple structures of any protein independent of the MSCS method. The DRoP output is an HTML format list of the solvent sites ordered by conservation rank in its population within the set of structures, along with renumbered and recolored PDB files for visualization and facile analysis. Here, we present a previously unpublished set of MSCS structures of bovine pancreatic ribonuclease A (RNase A) and use it together with published structures to illustrate the capabilities of DRoP.
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Affiliation(s)
- Bradley M Kearney
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.,Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina
| | - Michael Schwabe
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Kendra C Marcus
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Daniel M Roberts
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina
| | - Michelle Dechene
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina
| | - Paul Swartz
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.,Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina
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13
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Cao S, Chung S, Kim S, Li Z, Manor D, Buck M. K-Ras G-domain binding with signaling lipid phosphatidylinositol (4,5)-phosphate (PIP2): membrane association, protein orientation, and function. J Biol Chem 2019; 294:7068-7084. [PMID: 30792310 DOI: 10.1074/jbc.ra118.004021] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
Ras genes potently drive human cancers, with mutated proto-oncogene GTPase KRAS4B (K-Ras4B) being the most abundant isoform. Targeted inhibition of oncogenic gene products is considered the "holy grail" of present-day cancer therapy, and recent discoveries of small-molecule KRas4B inhibitors were made thanks to a deeper understanding of the structure and dynamics of this GTPase. Because interactions with biological membranes are key for Ras function, Ras-lipid interactions have become a major focus, especially because such interactions evidently involve both the Ras C terminus for lipid anchoring and its G-protein domain. Here, using NMR spectroscopy and molecular dynamics simulations complemented by biophysical- and cell-biology assays, we investigated the interaction between K-Ras4B with the signaling lipid phosphatidylinositol (4,5)-phosphate (PIP2). We discovered that the β2 and β3 strands as well as helices 4 and 5 of the GTPase G-domain bind to PIP2 and identified the specific residues in these structural elements employed in these interactions, likely occurring in two K-Ras4B orientation states relative to the membrane. Importantly, we found that some of these residues known to be oncogenic when mutated (D47K, D92N, K104M, and D126N) are critical for K-Ras-mediated transformation of fibroblast cells, but do not substantially affect basal and assisted nucleotide hydrolysis and exchange. Moreover, the K104M substitution abolished localization of K-Ras to the plasma membrane. The findings suggest that specific G-domain residues can critically regulate Ras function by mediating interactions with membrane-associated PIP2 lipids; these insights that may inform the future design of therapeutic reagents targeting Ras activity.
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Affiliation(s)
- Shufen Cao
- From the Departments of Physiology and Biophysics
| | | | | | - Zhenlu Li
- From the Departments of Physiology and Biophysics
| | - Danny Manor
- Nutrition, .,Pharmacology, and.,the Case Comprehensive Cancer Center and
| | - Matthias Buck
- From the Departments of Physiology and Biophysics, .,the Case Comprehensive Cancer Center and.,Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106 and.,Center for Proteomics and Bioinformatics, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
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14
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Knihtila R, Volmar AY, Meilleur F, Mattos C. Titration of ionizable groups in proteins using multiple neutron data sets from a single crystal: application to the small GTPase Ras. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2019; 75:111-115. [PMID: 30713162 DOI: 10.1107/s2053230x18018125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 12/20/2018] [Indexed: 11/11/2022]
Abstract
Neutron protein crystallography (NPC) reveals the three-dimensional structures of proteins, including the positions of H atoms. The technique is particularly suited to elucidate ambiguous catalytic steps in complex biochemical reactions. While NPC uniquely complements biochemical assays and X-ray structural analyses by revealing the protonation states of ionizable groups at and around the active site of enzymes, the technique suffers from a major drawback: large single crystals must be grown to compensate for the relatively low flux of neutron beams. However, in addition to revealing the positions of hydrogens involved in enzyme catalysis, NPC has the advantage over X-ray crystallography that the crystals do not suffer radiation damage. The lack of radiation damage can be exploited to conduct in crystallo parametric studies. Here, the use of a single crystal of the small GTPase Ras to collect three neutron data sets at pD 8.4, 9.0 and 9.4 is reported, enabling an in crystallo titration study using NPC. In addition to revealing the behavior of titratable groups in the active site, the data sets will allow the analysis of allosteric water-mediated communication networks across the molecule, particularly regarding Cys118 and three tyrosine residues central to these networks, Tyr32, Tyr96 and Tyr137, with pKa values expected to be in the range sampled in our experiments.
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Affiliation(s)
- Ryan Knihtila
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Alicia Y Volmar
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Flora Meilleur
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
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15
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Parker JA, Mattos C. The K-Ras, N-Ras, and H-Ras Isoforms: Unique Conformational Preferences and Implications for Targeting Oncogenic Mutants. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a031427. [PMID: 29038336 DOI: 10.1101/cshperspect.a031427] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ras controls a multitude of cellular signaling processes, including cell proliferation, differentiation, and apoptosis. Deregulation of Ras cycling often promotes tumorigenesis and various other developmental disorders, termed RASopothies. Although the structure of Ras has been known for many decades, it is still one of the most highly sought-after drug targets today, and is often referred to as "undruggable." At the center of this paradoxical protein is a lack of understanding of fundamental differences in the G domains between the highly similar Ras isoforms and common oncogenic mutations, despite the immense wealth of knowledge accumulated about this protein to date. A shift in the field during the past few years toward a high-resolution understanding of the structure confirms the hypothesis that each isoform and oncogenic mutation must be considered individually, and that not all Ras mutations are created equal. For the first time in Ras history, we have the ability to directly compare the structures of each wild-type isoform to construct a "base-line" understanding, which can then be used as a springboard for analyzing the effects of oncogenic mutations on the structure-function relationship in Ras. This is a fundamental and large step toward the goal of developing personalized therapies for patients with Ras-driven cancers and diseases.
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Affiliation(s)
- Jillian A Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
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16
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Parker JA, Volmar AY, Pavlopoulos S, Mattos C. K-Ras Populates Conformational States Differently from Its Isoform H-Ras and Oncogenic Mutant K-RasG12D. Structure 2018; 26:810-820.e4. [PMID: 29706533 DOI: 10.1016/j.str.2018.03.018] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 02/04/2018] [Accepted: 03/28/2018] [Indexed: 10/17/2022]
Abstract
Structures of wild-type K-Ras from crystals obtained in the presence of guanosine triphosphate (GTP) or its analogs have remained elusive. Of the K-Ras mutants, only K-RasG12D and K-RasQ61H are available in the PDB representing the activated form of the GTPase not in complex with other proteins. We present the crystal structure of wild-type K-Ras bound to the GTP analog GppCH2p, with K-Ras in the state 1 conformation. Signatures of conformational states obtained by one-dimensional proton NMR confirm that K-Ras has a more substantial population of state 1 in solution than H-Ras, which predominantly favors state 2. The oncogenic mutant K-RasG12D favors state 2, changing the balance of conformational states in favor of interactions with effector proteins. Differences in the population of conformational states between K-Ras and H-Ras, as well as between K-Ras and its mutants, can provide a structural basis for focused targeting of the K-Ras isoform in cancer-specific strategies.
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Affiliation(s)
- Jillian A Parker
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Alicia Y Volmar
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Spiro Pavlopoulos
- Center for Drug Discovery, Northeastern University, Boston, MA 02115, USA
| | - Carla Mattos
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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17
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Jukič M, Konc J, Gobec S, Janežič D. Identification of Conserved Water Sites in Protein Structures for Drug Design. J Chem Inf Model 2017; 57:3094-3103. [DOI: 10.1021/acs.jcim.7b00443] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Marko Jukič
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI−1000, Ljubljana, Slovenia
| | - Janez Konc
- National Institute of Chemistry, Hajdrihova 19, SI−1000, Ljubljana, Slovenia
- Faculty of
Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI−6000 Koper, Slovenia
| | - Stanislav Gobec
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, SI−1000, Ljubljana, Slovenia
| | - Dušanka Janežič
- Faculty of
Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI−6000 Koper, Slovenia
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18
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Johnson CW, Reid D, Parker JA, Salter S, Knihtila R, Kuzmic P, Mattos C. The small GTPases K-Ras, N-Ras, and H-Ras have distinct biochemical properties determined by allosteric effects. J Biol Chem 2017; 292:12981-12993. [PMID: 28630043 PMCID: PMC5546037 DOI: 10.1074/jbc.m117.778886] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/09/2017] [Indexed: 11/06/2022] Open
Abstract
H-Ras, K-Ras, and N-Ras are small GTPases that are important in the control of cell proliferation, differentiation, and survival, and their mutants occur frequently in human cancers. The G-domain, which catalyzes GTP hydrolysis and mediates downstream signaling, is 95% conserved between the Ras isoforms. Because of their very high sequence identity, biochemical studies done on H-Ras have been considered representative of all three Ras proteins. We show here that this is not a valid assumption. Using enzyme kinetic assays under identical conditions, we observed clear differences between the three isoforms in intrinsic catalysis of GTP by Ras in the absence and presence of the Ras-binding domain (RBD) of the c-Raf kinase protein (Raf-RBD). Given their identical active sites, isoform G-domain differences must be allosteric in origin, due to remote isoform-specific residues that affect conformational states. We present the crystal structure of N-Ras bound to a GTP analogue and interpret the kinetic data in terms of structural features specific for H-, K-, and N-Ras.
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Affiliation(s)
- Christian W Johnson
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Derion Reid
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Jillian A Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Shores Salter
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Ryan Knihtila
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | | | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115.
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19
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Kauke MJ, Traxlmayr MW, Parker JA, Kiefer JD, Knihtila R, McGee J, Verdine G, Mattos C, Wittrup KD. An engineered protein antagonist of K-Ras/B-Raf interaction. Sci Rep 2017; 7:5831. [PMID: 28724936 PMCID: PMC5517481 DOI: 10.1038/s41598-017-05889-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/05/2017] [Indexed: 12/31/2022] Open
Abstract
Ras is at the hub of signal transduction pathways controlling cell proliferation and survival. Its mutants, present in about 30% of human cancers, are major drivers of oncogenesis and render tumors unresponsive to standard therapies. Here we report the engineering of a protein scaffold for preferential binding to K-Ras G12D. This is the first reported inhibitor to achieve nanomolar affinity while exhibiting specificity for mutant over wild type (WT) K-Ras. Crystal structures of the protein R11.1.6 in complex with K-Ras WT and K-Ras G12D offer insight into the structural basis for specificity, highlighting differences in the switch I conformation as the major defining element in the higher affinity interaction. R11.1.6 directly blocks interaction with Raf and reduces signaling through the Raf/MEK/ERK pathway. Our results support greater consideration of the state of switch I and provide a novel tool to study Ras biology. Most importantly, this work makes an unprecedented contribution to Ras research in inhibitor development strategy by revealing details of a targetable binding surface. Unlike the polar interfaces found for Ras/effector interactions, the K-Ras/R11.1.6 complex reveals an extensive hydrophobic interface that can serve as a template to advance the development of high affinity, non-covalent inhibitors of K-Ras oncogenic mutants.
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Affiliation(s)
- Monique J Kauke
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Michael W Traxlmayr
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jillian A Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, 02115, USA
| | - Jonathan D Kiefer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Ryan Knihtila
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, 02115, USA
| | - John McGee
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Greg Verdine
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA.,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, 02115, USA
| | - K Dane Wittrup
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA. .,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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20
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Sayyed-Ahmad A, Prakash P, Gorfe AA. Distinct dynamics and interaction patterns in H- and K-Ras oncogenic P-loop mutants. Proteins 2017; 85:1618-1632. [PMID: 28498561 DOI: 10.1002/prot.25317] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 04/27/2017] [Accepted: 05/05/2017] [Indexed: 12/31/2022]
Abstract
Despite years of study, the structural or dynamical basis for the differential reactivity and oncogenicity of Ras isoforms and mutants remains unclear. In this study, we investigated the effects of amino acid variations on the structure and dynamics of wild type and oncogenic mutants G12D, G12V, and G13D of H- and K-Ras proteins. Based on data from µs-scale molecular dynamics simulations, we show that the overall structure of the proteins remains similar but there are important differences in dynamics and interaction networks. We identified differences in residue interaction patterns around the canonical switch and distal loop regions, and persistent sodium ion binding near the GTP particularly in the G13D mutants. Our results also suggest that different Ras variants have distinct local structural features and interactions with the GTP, variations that have the potential to affect GTP release and hydrolysis. Furthermore, we found that H-Ras proteins and particularly the G12V and G13D variants are significantly more flexible than their K-Ras counterparts. Finally, while most of the simulated proteins sampled the effector-interacting state 2 conformational state, G12V and G13D H-Ras adopted an open switch state 1 conformation that is defective in effector interaction. These differences have implications for Ras GTPase activity, effector or exchange factor binding, dimerization and membrane interaction. Proteins 2017; 85:1618-1632. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Abdallah Sayyed-Ahmad
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, 77030
| | - Priyanka Prakash
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, 77030
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, 77030
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21
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Zhao J, Nussinov R, Ma B. Allosteric control of antibody-prion recognition through oxidation of a disulfide bond between the CH and CL chains. Protein Eng Des Sel 2017; 30:67-76. [PMID: 27899437 PMCID: PMC5157118 DOI: 10.1093/protein/gzw065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/05/2016] [Accepted: 11/14/2016] [Indexed: 12/12/2022] Open
Abstract
Molecular details of the recognition of disordered antigens by their cognate antibodies have not been studied as extensively as folded protein antigens and much is still unknown. To follow the conformational changes in the antibody and cross-talk between its subunits and with antigens, we performed molecular dynamics (MD) simulations of the complex of Fab and prion-associated peptide in the apo and bound forms. We observed that the inter-chain disulfide bond in constant domains restrains the conformational changes of Fab, especially the loops in the CH1 domain, resulting in inhibition of the cross-talk between Fab subdomains that thereby may prevent prion peptide binding. We further identified several negative and positive correlations of motions between the peptide and Fab constant domains, which suggested structural cross-talks between the constant domains and the antigen. The cross-talk was influenced by the inter-chain disulfide bond, which reduced the number of paths between them. Importantly, network analysis of the complex and its bound water molecules observed that those water molecules form an integral part of the Fab/peptide complex network and potential allosteric pathways. On-going work focuses on developing strategies aimed to incorporate these new network communications-including the associated water molecules-toward the grand challenge of antibody design.
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Affiliation(s)
- Jun Zhao
- Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
- Department of Human Genetics and Molecular Medicine, Sackler Institute of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
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22
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Intrinsic K-Ras dynamics: A novel molecular dynamics data analysis method shows causality between residue pair motions. Sci Rep 2016; 6:37012. [PMID: 27845397 PMCID: PMC5109477 DOI: 10.1038/srep37012] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 10/21/2016] [Indexed: 12/11/2022] Open
Abstract
K-Ras is the most frequently mutated oncogene in human cancers, but there are still no drugs that directly target it in the clinic. Recent studies utilizing dynamics information show promising results for selectively targeting mutant K-Ras. However, despite extensive characterization, the mechanisms by which K-Ras residue fluctuations transfer allosteric regulatory information remain unknown. Understanding the direction of information flow can provide new mechanistic insights for K-Ras targeting. Here, we present a novel approach –conditional time-delayed correlations (CTC) – using the motions of all residue pairs of a protein to predict directionality in the allosteric regulation of the protein fluctuations. Analyzing nucleotide-dependent intrinsic K-Ras motions with the new approach yields predictions that agree with the literature, showing that GTP-binding stabilizes K-Ras motions and leads to residue correlations with relatively long characteristic decay times. Furthermore, our study is the first to identify driver-follower relationships in correlated motions of K-Ras residue pairs, revealing the direction of information flow during allosteric modulation of its nucleotide-dependent intrinsic activity: active K-Ras Switch-II region motions drive Switch-I region motions, while α-helix-3L7 motions control both. Our results provide novel insights for strategies that directly target mutant K-Ras.
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23
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Tunable allosteric library of caspase-3 identifies coupling between conserved water molecules and conformational selection. Proc Natl Acad Sci U S A 2016; 113:E6080-E6088. [PMID: 27681633 DOI: 10.1073/pnas.1603549113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The native ensemble of caspases is described globally by a complex energy landscape where the binding of substrate selects for the active conformation, whereas targeting an allosteric site in the dimer interface selects an inactive conformation that contains disordered active-site loops. Mutations and posttranslational modifications stabilize high-energy inactive conformations, with mostly formed, but distorted, active sites. To examine the interconversion of active and inactive states in the ensemble, we used detection of related solvent positions to analyze 4,995 waters in 15 high-resolution (<2.0 Å) structures of wild-type caspase-3, resulting in 450 clusters with the most highly conserved set containing 145 water molecules. The data show that regions of the protein that contact the conserved waters also correspond to sites of posttranslational modifications, suggesting that the conserved waters are an integral part of allosteric mechanisms. To test this hypothesis, we created a library of 19 caspase-3 variants through saturation mutagenesis in a single position of the allosteric site of the dimer interface, and we show that the enzyme activity varies by more than four orders of magnitude. Altogether, our database consists of 37 high-resolution structures of caspase-3 variants, and we demonstrate that the decrease in activity correlates with a loss of conserved water molecules. The data show that the activity of caspase-3 can be fine-tuned through globally desolvating the active conformation within the native ensemble, providing a mechanism for cells to repartition the ensemble and thus fine-tune activity through conformational selection.
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24
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Affiliation(s)
- Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
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25
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Lu S, Jang H, Muratcioglu S, Gursoy A, Keskin O, Nussinov R, Zhang J. Ras Conformational Ensembles, Allostery, and Signaling. Chem Rev 2016; 116:6607-65. [PMID: 26815308 DOI: 10.1021/acs.chemrev.5b00542] [Citation(s) in RCA: 253] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ras proteins are classical members of small GTPases that function as molecular switches by alternating between inactive GDP-bound and active GTP-bound states. Ras activation is regulated by guanine nucleotide exchange factors that catalyze the exchange of GDP by GTP, and inactivation is terminated by GTPase-activating proteins that accelerate the intrinsic GTP hydrolysis rate by orders of magnitude. In this review, we focus on data that have accumulated over the past few years pertaining to the conformational ensembles and the allosteric regulation of Ras proteins and their interpretation from our conformational landscape standpoint. The Ras ensemble embodies all states, including the ligand-bound conformations, the activated (or inactivated) allosteric modulated states, post-translationally modified states, mutational states, transition states, and nonfunctional states serving as a reservoir for emerging functions. The ensemble is shifted by distinct mutational events, cofactors, post-translational modifications, and different membrane compositions. A better understanding of Ras biology can contribute to therapeutic strategies.
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Affiliation(s)
- Shaoyong Lu
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China.,Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | | | | | | | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States.,Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University , Tel Aviv 69978, Israel
| | - Jian Zhang
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China
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26
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Marcus K, Mattos C. Direct Attack on RAS: Intramolecular Communication and Mutation-Specific Effects. Clin Cancer Res 2016; 21:1810-8. [PMID: 25878362 DOI: 10.1158/1078-0432.ccr-14-2148] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The crystal structure of RAS was first solved 25 years ago. In spite of tremendous and sustained efforts, there are still no drugs in the clinic that directly target this major driver of human cancers. Recent success in the discovery of compounds that bind RAS and inhibit signaling has fueled renewed enthusiasm, and in-depth understanding of the structure and function of RAS has opened new avenues for direct targeting. To succeed, we must focus on the molecular details of the RAS structure and understand at a high-resolution level how the oncogenic mutants impair function. Structural networks of intramolecular communication between the RAS active site and membrane-interacting regions on the G-domain are disrupted in oncogenic mutants. Although conserved across the isoforms, these networks are near hot spots of protein-ligand interactions with amino acid composition that varies among RAS proteins. These differences could have an effect on stabilization of conformational states of interest in attenuating signaling through RAS. The development of strategies to target these novel sites will add a fresh direction in the quest to conquer RAS-driven cancers. Clin Cancer Res; 21(8); 1810-8. ©2015 AACR. See all articles in this CCR Focus section, "Targeting RAS-Driven Cancers."
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Affiliation(s)
- Kendra Marcus
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.
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27
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Knihtila R, Holzapfel G, Weiss K, Meilleur F, Mattos C. Neutron Crystal Structure of RAS GTPase Puts in Question the Protonation State of the GTP γ-Phosphate. J Biol Chem 2015; 290:31025-36. [PMID: 26515069 DOI: 10.1074/jbc.m115.679860] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Indexed: 11/06/2022] Open
Abstract
RAS GTPase is a prototype for nucleotide-binding proteins that function by cycling between GTP and GDP, with hydrogen atoms playing an important role in the GTP hydrolysis mechanism. It is one of the most well studied proteins in the superfamily of small GTPases, which has representatives in a wide range of cellular functions. These proteins share a GTP-binding pocket with highly conserved motifs that promote hydrolysis to GDP. The neutron crystal structure of RAS presented here strongly supports a protonated γ-phosphate at physiological pH. This counters the notion that the phosphate groups of GTP are fully deprotonated at the start of the hydrolysis reaction, which has colored the interpretation of experimental and computational data in studies of the hydrolysis mechanism. The neutron crystal structure presented here puts in question our understanding of the pre-catalytic state associated with the hydrolysis reaction central to the function of RAS and other GTPases.
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Affiliation(s)
- Ryan Knihtila
- From the Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Genevieve Holzapfel
- the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, and
| | - Kevin Weiss
- the Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Flora Meilleur
- the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, and the Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Carla Mattos
- From the Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, the Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, and
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28
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Chavan TS, Muratcioglu S, Marszalek R, Jang H, Keskin O, Gursoy A, Nussinov R, Gaponenko V. Plasma membrane regulates Ras signaling networks. CELLULAR LOGISTICS 2015; 5:e1136374. [PMID: 27054048 PMCID: PMC4820813 DOI: 10.1080/21592799.2015.1136374] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Ras GTPases activate more than 20 signaling pathways, regulating such essential cellular functions as proliferation, survival, and migration. How Ras proteins control their signaling diversity is still a mystery. Several pieces of evidence suggest that the plasma membrane plays a critical role. Among these are: (1) selective recruitment of Ras and its effectors to particular localities allowing access to Ras regulators and effectors; (2) specific membrane-induced conformational changes promoting Ras functional diversity; and (3) oligomerization of membrane-anchored Ras to recruit and activate Raf. Taken together, the membrane does not only attract and retain Ras but also is a key regulator of Ras signaling. This can already be gleaned from the large variability in the sequences of Ras membrane targeting domains, suggesting that localization, environment and orientation are important factors in optimizing the function of Ras isoforms.
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Affiliation(s)
- Tanmay Sanjeev Chavan
- Department of Medicinal Chemistry; University of Illinois at Chicago; Chicago, IL USA
| | - Serena Muratcioglu
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Richard Marszalek
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
| | - Hyunbum Jang
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
| | - Ozlem Keskin
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Attila Gursoy
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Ruth Nussinov
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
- Sackler Institute of Molecular Medicine; Department of Human Genetics and Molecular Medicine; Sackler School of Medicine; Tel Aviv University; Tel Aviv, Israel
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
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Ting PY, Johnson CW, Fang C, Cao X, Graeber TG, Mattos C, Colicelli J. Tyrosine phosphorylation of RAS by ABL allosterically enhances effector binding. FASEB J 2015; 29:3750-61. [PMID: 25999467 PMCID: PMC4550377 DOI: 10.1096/fj.15-271510] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/11/2015] [Indexed: 01/07/2023]
Abstract
RAS proteins are signal transduction gatekeepers that mediate cell growth, survival, and differentiation through interactions with multiple effector proteins. The RAS effector RAS- and RAB-interacting protein 1 (RIN1) activates its own downstream effectors, the small GTPase RAB5 and the tyrosine kinase Abelson tyrosine-protein kinase (ABL), to modulate endocytosis and cytoskeleton remodeling. To identify ABL substrates downstream of RAS-to-RIN1 signaling, we examined human HEK293T cells overexpressing components of this pathway. Proteomic analysis revealed several novel phosphotyrosine peptides, including Harvey rat sarcoma oncogene (HRAS)-pTyr(137). Here we report that ABL phosphorylates tyrosine 137 of H-, K-, and NRAS. Increased RIN1 levels enhanced HRAS-Tyr(137) phosphorylation by nearly 5-fold, suggesting that RAS-stimulated RIN1 can drive ABL-mediated RAS modification in a feedback circuit. Tyr(137) is well conserved among RAS orthologs and is part of a transprotein H-bond network. Crystal structures of HRAS(Y137F) and HRAS(Y137E) revealed conformation changes radiating from the mutated residue. Although consistent with Tyr(137) participation in allosteric control of HRAS function, the mutations did not alter intrinsic GTP hydrolysis rates in vitro. HRAS-Tyr(137) phosphorylation enhanced HRAS signaling capacity in cells, however, as reflected by a 4-fold increase in the association of phosphorylated HRAS(G12V) with its effector protein RAF proto-oncogene serine/threonine protein kinase 1 (RAF1). These data suggest that RAS phosphorylation at Tyr(137) allosterically alters protein conformation and effector binding, providing a mechanism for effector-initiated modulation of RAS signaling.
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Affiliation(s)
| | | | | | | | | | | | - John Colicelli
- Correspondence: University of California, Los Angeles, Box 951737, 350C BSRB, Los Angeles, CA 90095-1737, USA. E-mail:
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Fetics SK, Guterres H, Kearney BM, Buhrman G, Ma B, Nussinov R, Mattos C. Allosteric effects of the oncogenic RasQ61L mutant on Raf-RBD. Structure 2015; 23:505-516. [PMID: 25684575 PMCID: PMC7755167 DOI: 10.1016/j.str.2014.12.017] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/07/2014] [Accepted: 12/17/2014] [Indexed: 10/24/2022]
Abstract
The Ras/Raf/MEK/ERK signal transduction pathway is a major regulator of cell proliferation activated by Ras-guanosine triphosphate (GTP). The oncogenic mutant RasQ61L is not able to hydrolyze GTP in the presence of Raf and thus is a constitutive activator of this mitogenic pathway. The Ras/Raf interaction is essential for the activation of the Raf kinase domain through a currently unknown mechanism. We present the crystal structures of the Ras-GppNHp/Raf-RBD and RasQ61L-GppNHp/Raf-RBD complexes, which, in combination with MD simulations, reveal differences in allosteric interactions leading from the Ras/Raf interface to the Ras calcium-binding site and to the remote Raf-RBD loop L4. In the presence of Raf, the RasQ61L mutant has a rigid switch II relative to the wild-type and increased flexibility at the interface with switch I, which propagates across Raf-RBD. We show that in addition to local perturbations on Ras, RasQ61L has substantial long-range effects on the Ras allosteric lobe and on Raf-RBD.
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Affiliation(s)
- Susan K Fetics
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Hugo Guterres
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Bradley M Kearney
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Greg Buhrman
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Buyong Ma
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Cancer and Inflammation Program, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Genetics, Sackler Institute of Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA.
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Parker JA, Mattos C. The Ras-Membrane Interface: Isoform-specific Differences in The Catalytic Domain. Mol Cancer Res 2015; 13:595-603. [PMID: 25566993 DOI: 10.1158/1541-7786.mcr-14-0535] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/11/2014] [Indexed: 11/16/2022]
Abstract
The small GTPase Ras is mutated in about 20% of human cancers, primarily at active site amino acid residues G12, G13, and Q61. Thus, structural biology research has focused on the active site, impairment of GTP hydrolysis by oncogenic mutants, and characterization of protein-protein interactions in the effector lobe half of the protein. The C-terminal hypervariable region has increasingly gained attention due to its importance in H-Ras, N-Ras, and K-Ras differences in membrane association. A high-resolution molecular view of the Ras-membrane interaction involving the allosteric lobe of the catalytic domain has lagged behind, although evidence suggests that it contributes to isoform specificity. The allosteric lobe has recently gained interest for harboring potential sites for more selective targeting of this elusive "undruggable" protein. The present review reveals critical insight that isoform-specific differences appear prominently at these potentially targetable sites and integrates these differences with knowledge of Ras plasma membrane localization, with the intent to better understand the structure-function relationships needed to design isoform-specific Ras inhibitors.
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Affiliation(s)
- Jillian A Parker
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts
| | - Carla Mattos
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts.
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Communication routes in ARID domains between distal residues in helix 5 and the DNA-binding loops. PLoS Comput Biol 2014; 10:e1003744. [PMID: 25187961 PMCID: PMC4154638 DOI: 10.1371/journal.pcbi.1003744] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Accepted: 06/12/2014] [Indexed: 11/19/2022] Open
Abstract
ARID is a DNA-binding domain involved in several transcriptional regulatory processes, including cell-cycle regulation and embryonic development. ARID domains are also targets of the Human Cancer Protein Interaction Network. Little is known about the molecular mechanisms related to conformational changes in the family of ARID domains. Thus, we have examined their structural dynamics to enrich the knowledge on this important family of regulatory proteins. In particular, we used an approach that integrates atomistic simulations and methods inspired by graph theory. To relate these properties to protein function we studied both the free and DNA-bound forms. The interaction with DNA not only stabilizes the conformations of the DNA-binding loops, but also strengthens pre-existing paths in the native ARID ensemble for long-range communication to those loops. Residues in helix 5 are identified as critical mediators for intramolecular communication to the DNA-binding regions. In particular, we identified a distal tyrosine that plays a key role in long-range communication to the DNA-binding loops and that is experimentally known to impair DNA-binding. Mutations at this tyrosine and in other residues of helix 5 are also demonstrated, by our approach, to affect the paths of communication to the DNA-binding loops and alter their native dynamics. Overall, our results are in agreement with a scenario in which ARID domains exist as an ensemble of substates, which are shifted by external perturbation, such as the interaction with DNA. Conformational changes at the DNA-binding loops are transmitted long-range by intramolecular paths, which have their heart in helix 5.
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