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Kim Y, Maltseva N, Tesar C, Jedrzejczak R, Endres M, Ma H, Dugan HL, Stamper CT, Chang C, Li L, Changrob S, Zheng NY, Huang M, Ramanathan A, Wilson P, Michalska K, Joachimiak A. Epitopes recognition of SARS-CoV-2 nucleocapsid RNA binding domain by human monoclonal antibodies. iScience 2024; 27:108976. [PMID: 38327783 PMCID: PMC10847736 DOI: 10.1016/j.isci.2024.108976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/02/2023] [Accepted: 01/16/2024] [Indexed: 02/09/2024] Open
Abstract
Coronavirus nucleocapsid protein (NP) of SARS-CoV-2 plays a central role in many functions important for virus proliferation including packaging and protecting genomic RNA. The protein shares sequence, structure, and architecture with nucleocapsid proteins from betacoronaviruses. The N-terminal domain (NPRBD) binds RNA and the C-terminal domain is responsible for dimerization. After infection, NP is highly expressed and triggers robust host immune response. The anti-NP antibodies are not protective and not neutralizing but can effectively detect viral proliferation soon after infection. Two structures of SARS-CoV-2 NPRBD were determined providing a continuous model from residue 48 to 173, including RNA binding region and key epitopes. Five structures of NPRBD complexes with human mAbs were isolated using an antigen-bait sorting. Complexes revealed a distinct complement-determining regions and unique sets of epitope recognition. This may assist in the early detection of pathogens and designing peptide-based vaccines. Mutations that significantly increase viral load were mapped on developed, full length NP model, likely impacting interactions with host proteins and viral RNA.
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Affiliation(s)
- Youngchang Kim
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Natalia Maltseva
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Christine Tesar
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Robert Jedrzejczak
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Michael Endres
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Heng Ma
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Haley L. Dugan
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Christopher T. Stamper
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Changsoo Chang
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Lei Li
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Siriruk Changrob
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Nai-Ying Zheng
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Min Huang
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
| | - Arvind Ramanathan
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Patrick Wilson
- Gale and Ira Drukier Institute for Children’s Health, Weill Cornell Medicine, New York, NY 10021, USA
| | - Karolina Michalska
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Andrzej Joachimiak
- Center for Structural Biology of Infectious Diseases, Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60367, USA
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL 60439, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60367, USA
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2
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Schröder GC, O'Dell WB, Webb SP, Agarwal PK, Meilleur F. Capture of activated dioxygen intermediates at the copper-active site of a lytic polysaccharide monooxygenase. Chem Sci 2022; 13:13303-13320. [PMID: 36507176 PMCID: PMC9683017 DOI: 10.1039/d2sc05031e] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/19/2022] [Indexed: 11/24/2022] Open
Abstract
Metalloproteins perform a diverse array of redox-related reactions facilitated by the increased chemical functionality afforded by their metallocofactors. Lytic polysaccharide monooxygenases (LPMOs) are a class of copper-dependent enzymes that are responsible for the breakdown of recalcitrant polysaccharides via oxidative cleavage at the glycosidic bond. The activated copper-oxygen intermediates and their mechanism of formation remains to be established. Neutron protein crystallography which permits direct visualization of protonation states was used to investigate the initial steps of oxygen activation directly following active site copper reduction in Neurospora crassa LPMO9D. Herein, we cryo-trap an activated dioxygen intermediate in a mixture of superoxo and hydroperoxo states, and we identify the conserved second coordination shell residue His157 as the proton donor. Density functional theory calculations indicate that both superoxo and hydroperoxo active site states are stable. The hydroperoxo formed is potentially an early LPMO catalytic reaction intermediate or the first step in the mechanism of hydrogen peroxide formation in the absence of substrate. We observe that the N-terminal amino group of the copper coordinating His1 remains doubly protonated directly following molecular oxygen reduction by copper. Aided by molecular dynamics and mining minima free energy calculations we establish that the conserved second-shell His161 in MtPMO3* displays conformational flexibility in solution and that this flexibility is also observed, though to a lesser extent, in His157 of NcLPMO9D. The imidazolate form of His157 observed in our structure following oxygen intermediate protonation can be attributed to abolished His157 flexibility due steric hindrance in the crystal as well as the solvent-occluded active site environment due to crystal packing. A neutron crystal structure of NcLPMO9D at low pH further supports occlusion of the active site since His157 remains singly protonated even at acidic conditions.
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Affiliation(s)
- Gabriela C. Schröder
- Department of Molecular and Structural Biochemistry, North Carolina State UniversityRaleighNC 27695USA,Neutron Scattering Division, Oak Ridge National LaboratoryOak RidgeTN 37831USA
| | - William B. O'Dell
- Department of Molecular and Structural Biochemistry, North Carolina State UniversityRaleighNC 27695USA,Neutron Scattering Division, Oak Ridge National LaboratoryOak RidgeTN 37831USA
| | - Simon P. Webb
- VeraChem LLC12850 Middlebrook Rd. Ste 205GermantownMD 20874-5244USA
| | - Pratul K. Agarwal
- Department of Physiological Sciences and High-Performance Computing Center, Oklahoma State UniversityStillwaterOK 74078USA
| | - Flora Meilleur
- Department of Molecular and Structural Biochemistry, North Carolina State UniversityRaleighNC 27695USA,Neutron Scattering Division, Oak Ridge National LaboratoryOak RidgeTN 37831USA
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3
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Agarwal PK, Bernard DN, Bafna K, Doucet N. Enzyme dynamics: Looking beyond a single structure. ChemCatChem 2020; 12:4704-4720. [PMID: 33897908 PMCID: PMC8064270 DOI: 10.1002/cctc.202000665] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Indexed: 12/23/2022]
Abstract
Conventional understanding of how enzymes function strongly emphasizes the role of structure. However, increasing evidence clearly indicates that enzymes do not remain fixed or operate exclusively in or close to their native structure. Different parts of the enzyme (from individual residues to full domains) undergo concerted motions on a wide range of time-scales, including that of the catalyzed reaction. Information obtained on these internal motions and conformational fluctuations has so far uncovered and explained many aspects of enzyme mechanisms, which could not have been understood from a single structure alone. Although there is wide interest in understanding enzyme dynamics and its role in catalysis, several challenges remain. In addition to technical difficulties, the vast majority of investigations are performed in dilute aqueous solutions, where conditions are significantly different than the cellular milieu where a large number of enzymes operate. In this review, we discuss recent developments, several challenges as well as opportunities related to this topic. The benefits of considering dynamics as an integral part of the enzyme function can also enable new means of biocatalysis, engineering enzymes for industrial and medicinal applications.
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Affiliation(s)
- Pratul K. Agarwal
- Department of Physiological Sciences and High-Performance Computing Center, Oklahoma State University, Stillwater, Oklahoma 74078
- Arium BioLabs, 2519 Caspian Drive, Knoxville, Tennessee 37932
| | - David N. Bernard
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Khushboo Bafna
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Nicolas Doucet
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Structure, and Engineering, 1045 Avenue de la Médecine, Université Laval, Québec, QC, G1V 0A6, Canada
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4
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Visualizing Rev1 catalyze protein-template DNA synthesis. Proc Natl Acad Sci U S A 2020; 117:25494-25504. [PMID: 32999062 DOI: 10.1073/pnas.2010484117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During DNA replication, replicative DNA polymerases may encounter DNA lesions, which can stall replication forks. One way to prevent replication fork stalling is through the recruitment of specialized translesion synthesis (TLS) polymerases that have evolved to incorporate nucleotides opposite DNA lesions. Rev1 is a specialized TLS polymerase that bypasses abasic sites, as well as minor-groove and exocyclic guanine adducts. Lesion bypass is accomplished using a unique protein-template mechanism in which the templating base is evicted from the DNA helix and the incoming dCTP hydrogen bonds with an arginine side chain of Rev1. To understand the protein-template mechanism at an atomic level, we employed a combination of time-lapse X-ray crystallography, molecular dynamics simulations, and DNA enzymology on the Saccharomyces cerevisiae Rev1 protein. We find that Rev1 evicts the templating base from the DNA helix prior to binding the incoming nucleotide. Binding the incoming nucleotide changes the conformation of the DNA substrate to orient it for nucleotidyl transfer, although this is not coupled to large structural changes in Rev1 like those observed with other DNA polymerases. Moreover, we found that following nucleotide incorporation, Rev1 converts the pyrophosphate product to two monophosphates, which drives the reaction in the forward direction and prevents pyrophosphorolysis. Following nucleotide incorporation, the hydrogen bonds between the incorporated nucleotide and the arginine side chain are broken, but the templating base remains extrahelical. These postcatalytic changes prevent potentially mutagenic processive synthesis by Rev1 and facilitate dissociation of the DNA product from the enzyme.
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5
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Transient Unfolding and Long-Range Interactions in Viral BCL2 M11 Enable Binding to the BECN1 BH3 Domain. Biomolecules 2020; 10:biom10091308. [PMID: 32932757 PMCID: PMC7564285 DOI: 10.3390/biom10091308] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 01/07/2023] Open
Abstract
Viral BCL2 proteins (vBCL2s) help to sustain chronic infection of host proteins to inhibit apoptosis and autophagy. However, details of conformational changes in vBCL2s that enable binding to BH3Ds remain unknown. Using all-atom, multiple microsecond-long molecular dynamic simulations (totaling 17 μs) of the murine γ-herpesvirus 68 vBCL2 (M11), and statistical inference techniques, we show that regions of M11 transiently unfold and refold upon binding of the BH3D. Further, we show that this partial unfolding/refolding within M11 is mediated by a network of hydrophobic interactions, which includes residues that are 10 Å away from the BH3D binding cleft. We experimentally validate the role of these hydrophobic interactions by quantifying the impact of mutating these residues on binding to the Beclin1/BECN1 BH3D, demonstrating that these mutations adversely affect both protein stability and binding. To our knowledge, this is the first study detailing the binding-associated conformational changes and presence of long-range interactions within vBCL2s.
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6
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Hu QH, Williams MT, Shulgina I, Fossum CJ, Weeks KM, Adams LM, Reinhardt CR, Musier-Forsyth K, Hati S, Bhattacharyya S. Editing Domain Motions Preorganize the Synthetic Active Site of Prolyl-tRNA Synthetase. ACS Catal 2020; 10:10229-10242. [PMID: 34295570 DOI: 10.1021/acscatal.0c02381] [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] [Indexed: 11/29/2022]
Abstract
Prolyl-tRNA synthetases (ProRSs) catalyze the covalent attachment of proline onto cognate tRNAs, an indispensable step for protein synthesis in all living organisms. ProRSs are modular enzymes and the "prokaryotic-like" ProRSs are distinguished from "eukaryotic-like" ProRSs by the presence of an editing domain (INS) inserted between motifs 2 and 3 of the main catalytic domain. Earlier studies suggested the presence of coupled-domain dynamics could contribute to catalysis; however, the role that the distal, highly mobile INS domain plays in catalysis at the synthetic active site is not completely understood. In the present study, a combination of theoretical and experimental approaches has been used to elucidate the precise role of INS domain dynamics. Quantum mechanical/molecular mechanical simulations were carried out to model catalytic Pro-AMP formation by Enterococcus faecalis ProRS. The energetics of the adenylate formation by the wild-type enzyme was computed and contrasted with variants containing active site mutations, as well as a deletion mutant lacking the INS domain. The combined results revealed that two distinct types of dynamics contribute to the enzyme's catalytic power. One set of motions is intrinsic to the INS domain and leads to conformational preorganization that is essential for catalysis. A second type of motion, stemming from the electrostatic reorganization of active site residues, impacts the height and width of the energy profile and has a critical role in fine tuning the substrate orientation to facilitate reactive collisions. Thus, motions in a distal domain can preorganize the active site of an enzyme to optimize catalysis.
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Affiliation(s)
- Quin H. Hu
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Murphi T. Williams
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Irina Shulgina
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Carl J. Fossum
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Katelyn M. Weeks
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Lauren M. Adams
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Clorice R. Reinhardt
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sanchita Hati
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
| | - Sudeep Bhattacharyya
- Department of Chemistry and Biochemistry, University of Wisconsin, Eau Claire, Wisconsin 54701, United States
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7
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Hoitsma NM, Whitaker AM, Beckwitt EC, Jang S, Agarwal P, Van Houten B, Freudenthal BD. AP-endonuclease 1 sculpts DNA through an anchoring tyrosine residue on the DNA intercalating loop. Nucleic Acids Res 2020; 48:7345-7355. [PMID: 32542366 PMCID: PMC7367167 DOI: 10.1093/nar/gkaa496] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/30/2020] [Accepted: 06/01/2020] [Indexed: 02/07/2023] Open
Abstract
Base excision repair (BER) maintains genomic stability through the repair of DNA damage. Within BER, AP-endonuclease 1 (APE1) is a multifunctional enzyme that processes DNA intermediates through its backbone cleavage activity. To accomplish these repair activities, APE1 must recognize and accommodate several diverse DNA substrates. This is hypothesized to occur through a DNA sculpting mechanism where structural adjustments of the DNA substrate are imposed by the protein; however, how APE1 uniquely sculpts each substrate within a single rigid active site remains unclear. Here, we utilize structural and biochemical approaches to probe the DNA sculpting mechanism of APE1, specifically by characterizing a protein loop that intercalates the minor groove of the DNA (termed the intercalating loop). Pre-steady-state kinetics reveal a tyrosine residue within the intercalating loop (Y269) that is critical for AP-endonuclease activity. Using X-ray crystallography and molecular dynamics simulations, we determined the Y269 residue acts to anchor the intercalating loop on abasic DNA. Atomic force microscopy reveals the Y269 residue is required for proper DNA bending by APE1, providing evidence for the importance of this mechanism. We conclude that this previously unappreciated tyrosine residue is key to anchoring the intercalating loop and stabilizing the DNA in the APE1 active site.
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Affiliation(s)
- Nicole M Hoitsma
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Emily C Beckwitt
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Laboratory of DNA Replication, The Rockefeller University, New York, NY 10065, USA
- Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Sunbok Jang
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Pratul K Agarwal
- Department of Physiological Sciences and High-Performance Computing Center, Oklahoma State University, Stillwater, OK 74078, USA
| | - Bennett Van Houten
- Program in Molecular Biophysics and Structural Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
- UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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8
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Nambiar D, Sharma O, Duff MR, Howell EE. Effects of Osmolytes on Ligand Binding to Dihydropteroate Synthase from Bacillus anthracis. J Phys Chem B 2020; 124:6212-6224. [PMID: 32580556 DOI: 10.1021/acs.jpcb.0c03311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Osmolyte interactions with ligands can affect their affinity for proteins and are dependent upon the cosolute and the functional groups of the ligand. Here, we explored ligand binding to Bacillus anthracis dihydropteroate synthase (BaDHPS) under osmotic stress conditions. Osmolyte effects were specific to the cosolute and ligand, suggesting interaction of the osmolytes with the free ligands in solution. The association rates of pterin pyrophosphate were mostly unaffected by the osmolytes, except for a 2-fold decrease in the presence of 1 M trehalose, while the dissociation rates decreased in most osmolyte solutions. The viscosity and dielectric constant of the solution did not correlate with the effects of the osmolytes. Experimental results were compared with predicted preferential interaction coefficients (Δμ23/RT) between the osmolytes and ligands. The Δμ23/RT were able to predict the experimental data for most of the osmolytes. Trehalose and proline effects did not correlate with the predicted values, indicating that these two osmolytes may affect binding in more complex ways than simple preferential interactions. Additionally, osmolytes weakly interacted with the sulfa drug sulfathiazole, which altered its affinity for BaDHPS, suggesting that these types of weak interactions can also impact drug binding. As osmolytes affect ligands binding to two different folate cycle enzymes (DHFRs and DHPS), we predicted how ligand binding to other folate cycle enzymes will be altered by the presence of osmolytes.
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Affiliation(s)
- Deepika Nambiar
- Department of Biochemistry & Cellular and Molecular Biology Department, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Ojaswini Sharma
- Department of Biochemistry & Cellular and Molecular Biology Department, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Michael R Duff
- Department of Biochemistry & Cellular and Molecular Biology Department, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Elizabeth E Howell
- Department of Biochemistry & Cellular and Molecular Biology Department, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
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9
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Darbari VC, Ciccone J, Patel JS, Islam B, Agarwal PK, Haider S. Electrostatic Switching Controls Channel Dynamics of the Sensor Protein VirB10 in A. tumefaciens Type IV Secretion System. ACS OMEGA 2020; 5:3271-3281. [PMID: 32118142 PMCID: PMC7045316 DOI: 10.1021/acsomega.9b03313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/20/2020] [Indexed: 05/19/2023]
Abstract
Type IV secretion systems are large nanomachines assembled across the bacterial cell envelope for effector translocation and conjugation. VirB10 traverses the inner and outer membranes, sensing cellular signals for coordinating the conformational switch for pilus biogenesis and/or secretion. Mutations uncoupling secretion from pilus biogenesis were identified in Agrobacterium tumefaciens VirB10 including a gating defect mutation G272R that made VirB10 unresponsive to intracellular ATP, causing unregulated secretion of VirE2 in a contact-independent manner. Comparative long-timescale molecular dynamics of the wild type and G272R mutant of the A. tumefaciens VirB10CTD tetradecamer reveals how the G272R mutation locks the oligomer in a rigid conformation by swapping the ionic interactions between the loops from the β-barrel close to the inner leaflet of the outer membrane. This electrostatic switching changes the allosteric communication pathway from the extracellular loop to the base of the barrel, suggesting that the local conformational dynamics in the loops can gate information across VirB10.
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Affiliation(s)
- Vidya Chandran Darbari
- School
of Biological and Chemical Sciences, Queen
Mary University of London, Mile End Road, London E1 4NS, United Kingdom
- E-mail: . Tel: +44 (0)
20 7882 6360 (V.C.D.)
| | - Jonah Ciccone
- Department
of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, WC1N 1AX London, United Kingdom
| | - Jagdish Suresh Patel
- Department
of Biological Sciences, University of Idaho, C/O IRIC 333, 875 Perimeter MS 1122, Moscow, Idaho 83844-1122, United States
| | - Barira Islam
- Centre
for Biomarker Research, School of Applied Sciences, University of Huddersfield, HD1 3DH Huddersfield, United Kingdom
| | - Pratul K Agarwal
- Department
of Biochemistry & Cellular and Molecular Biology Department, University of Tennessee-Knoxville, Knoxville, Tennessee 37996, United States
| | - Shozeb Haider
- Department
of Pharmaceutical and Biological Chemistry, University College London School of Pharmacy, WC1N 1AX London, United Kingdom
- E-mail: . Tel: +44 (0) 20 7753 5883 (S.H.)
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10
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Narayanan C, Bernard DN, Létourneau M, Gagnon J, Gagné D, Bafna K, Calmettes C, Couture JF, Agarwal PK, Doucet N. Insights into Structural and Dynamical Changes Experienced by Human RNase 6 upon Ligand Binding. Biochemistry 2020; 59:755-765. [PMID: 31909602 PMCID: PMC7296828 DOI: 10.1021/acs.biochem.9b00888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ribonuclease 6 (RNase 6) is one of eight catalytically active human pancreatic-type RNases that belong to a superfamily of rapidly evolving enzymes. Like some of its human homologues, RNase 6 exhibits host defense properties such as antiviral and antibacterial activities. Recently solved crystal structures of this enzyme in its nucleotide-free form show the conservation of the prototypical kidney-shaped fold preserved among vertebrate RNases, in addition to revealing the presence of a unique secondary active site. In this study, we determine the structural and conformational properties experienced by RNase 6 upon binding to substrate and product analogues. We present the first crystal structures of RNase 6 bound to a nucleotide ligand (adenosine 5'-monophosphate), in addition to RNase 6 bound to phosphate ions. While the enzyme preserves B2 subsite ligand preferences, our results show a lack of typical B2 subsite interactions normally observed in homologous ligand-bound RNases. A comparison of the dynamical properties of RNase 6 in its apo-, substrate-, and product-bound states highlight the unique dynamical properties experienced on time scales ranging from nano- to milliseconds. Overall, our results confirm the specific evolutionary adaptation of RNase 6 relative to its unique catalytic and biological activities.
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Affiliation(s)
- Chitra Narayanan
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - David N. Bernard
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Myriam Létourneau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Jacinthe Gagnon
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Donald Gagné
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
| | - Khushboo Bafna
- Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Charles Calmettes
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
- PROTEO, the Québec Network for Research on Protein Function, Engineering, and Applications, 1045 Avenue de la Médecine, Université Laval, Quebec, G1V 0A6, Canada
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
| | - Pratul K. Agarwal
- Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Nicolas Doucet
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Université du Québec, 531 Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada
- PROTEO, the Québec Network for Research on Protein Function, Engineering, and Applications, 1045 Avenue de la Médecine, Université Laval, Quebec, G1V 0A6, Canada
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11
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Hester KP, Bhattarai K, Jiang H, Agarwal PK, Pope C. Engineering Dynamic Surface Peptide Networks on Butyrylcholinesterase G117H for Enhanced Organophosphosphorus Anticholinesterase Catalysis. Chem Res Toxicol 2019; 32:1801-1810. [PMID: 31411024 DOI: 10.1021/acs.chemrestox.9b00146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The single residue mutation of butyrylcholinesterase (BChEG117H) hydrolyzes a number of organophosphosphorus (OP) anticholinesterases. Whereas other BChE active site/proximal mutations have been investigated, none are sufficiently active to be prophylactically useful. In a fundamentally different computer simulations driven strategy, we identified a surface peptide loop (residues 278-285) exhibiting dynamic motions during catalysis and modified it via residue insertions. We evaluated these loop mutants using computer simulations, substrate kinetics, resistance to inhibition, and enzyme reactivation assays using both the choline ester and OP substrates. A slight but significant increase in reactivation was noted with paraoxon with one of the mutants, and changes in KM and catalytic efficiency were noted in others. Simulations suggested weaker interactions between OP versus choline substrates and the active site of all engineered versions of the enzyme. The results indicate that an improvement of OP anticholinesterase hydrolysis through surface loop engineering may be a more effective strategy in an enzyme with higher intrinsic OP compound hydrolase activity.
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Affiliation(s)
- Kirstin P Hester
- Department of Physiological Sciences , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Krishna Bhattarai
- Department of Entomology and Plant Pathology , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Haobo Jiang
- Department of Entomology and Plant Pathology , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Pratul K Agarwal
- Department of Biochemistry & Cellular and Molecular Biology , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Arium BioLabs , 2519 Caspian Drive , Knoxville , Tennessee 37932 , United States
| | - Carey Pope
- Department of Physiological Sciences , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
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12
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Bafna K, Narayanan C, Chennubhotla SC, Doucet N, Agarwal PK. Nucleotide substrate binding characterization in human pancreatic-type ribonucleases. PLoS One 2019; 14:e0220037. [PMID: 31393891 PMCID: PMC6687278 DOI: 10.1371/journal.pone.0220037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/07/2019] [Indexed: 12/15/2022] Open
Abstract
Human genome contains a group of more than a dozen similar genes with diverse biological functions including antiviral, antibacterial and angiogenesis activities. The characterized gene products of this group show significant sequence similarity and a common structural fold associated with binding and cleavage of ribonucleic acid (RNA) substrates. Therefore, these proteins have been categorized as members of human pancreatic-type ribonucleases (hRNases). hRNases differ in cell/tissue localization and display distinct substrate binding preferences and a wide range of ribonucleolytic catalytic efficiencies. Limited information is available about structural and dynamical properties that influence this diversity among these homologous RNases. Here, we use computer simulations to characterize substrate interactions, electrostatics and dynamical properties of hRNases 1-7 associated with binding to two nucleotide substrates (ACAC and AUAU). Results indicate that even with complete conservation of active-site catalytic triad associated with ribonucleolytic activity, these enzymes show significant differences in substrate interactions. Detailed characterization suggests that in addition to binding site electrostatic and van der Waals interactions, dynamics of distal regions may also play a role in binding. Another key insight is that a small difference in temperature of 300 K (used in experimental studies) and 310 K (physiological temperature) shows significant changes in enzyme-substrate interactions.
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Affiliation(s)
- Khushboo Bafna
- Genome Science and Technology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Chitra Narayanan
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada
| | - S. Chakra Chennubhotla
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada
- PROTEO, the Quebec Network for Research on Protein Function, Structure, and Engineering, Université Laval, Québec, Quebec, Canada
| | - Pratul K. Agarwal
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, United States of America
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13
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Abstract
Even after a century of investigation, our understanding of how enzymes work remains far from complete. In particular, several factors that enable enzymes to achieve high catalytic efficiencies remain only poorly understood. A number of theories have been developed, which propose or reaffirm that enzymes work as structural scaffolds, serving to bring together and properly orient the participants so that the reaction can proceed; therefore, leading to enzymes being viewed as only passive participants in the catalyzed reaction. A growing body of evidence shows that enzymes are not rigid structures but are constantly undergoing a wide range of internal motions and conformational fluctuations. In this Perspective, on the basis of studies from our group, we discuss the emerging biophysical model of enzyme catalysis that provides a detailed understanding of the interconnection among internal protein motions, conformational substates, enzyme mechanisms, and the catalytic efficiency of enzymes. For a number of enzymes, networks of conserved residues that extend from the surface of the enzyme all the way to the active site have been discovered. These networks are hypothesized to serve as pathways of energy transfer that enables thermodynamical coupling of the surrounding solvent with enzyme catalysis and play a role in promoting enzyme function. Additionally, the role of enzyme structure and electrostatic effects has been well acknowledged for quite some time. Collectively, the recent knowledge gained about enzyme mechanisms suggests that the conventional paradigm of enzyme structure encoding function is incomplete and needs to be extended to structure encodes dynamics, and together these enzyme features encode function including catalytic rate acceleration.
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Affiliation(s)
- Pratul K Agarwal
- Department of Biochemistry & Cellular and Molecular Biology , University of Tennessee , Knoxville , Tennessee 37996 , United States
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14
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Shukla S, Bafna K, Gullett C, Myles DAA, Agarwal PK, Cuneo MJ. Differential Substrate Recognition by Maltose Binding Proteins Influenced by Structure and Dynamics. Biochemistry 2018; 57:5864-5876. [PMID: 30204415 PMCID: PMC6189639 DOI: 10.1021/acs.biochem.8b00783] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The genome of the hyperthermophile Thermotoga maritima contains three isoforms of maltose binding protein (MBP) that are high-affinity receptors for di-, tri-, and tetrasaccharides. Two of these proteins (tmMBP1 and tmMBP2) share significant sequence identity, approximately 90%, while the third (tmMBP3) shares less than 40% identity. MBP from Escherichia coli (ecMBP) shares 35% sequence identity with the tmMBPs. This subset of MBP isoforms offers an interesting opportunity to investigate the mechanisms underlying the evolution of substrate specificity and affinity profiles in a genome where redundant MBP genes are present. In this study, the X-ray crystal structures of tmMBP1, tmMBP2, and tmMBP3 are reported in the absence and presence of oligosaccharides. tmMBP1 and tmMBP2 have binding pockets that are larger than that of tmMBP3, enabling them to bind to larger substrates, while tmMBP1 and tmMBP2 also undergo substrate-induced hinge bending motions (∼52°) that are larger than that of tmMBP3 (∼35°). Small-angle X-ray scattering was used to compare protein behavior in solution, and computer simulations provided insights into dynamics of these proteins. Comparing quantitative protein-substrate interactions and dynamical properties of tmMBPs with those of the promiscuous ecMBP and disaccharide selective Thermococcus litoralis MBP provides insights into the features that enable selective binding. Collectively, the results provide insights into how the structure and dynamics of tmMBP homologues enable them to differentiate between a myriad of chemical entities while maintaining their common fold.
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Affiliation(s)
- Shantanu Shukla
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Khushboo Bafna
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee
| | - Caeley Gullett
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Dean A. A. Myles
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, Tennessee
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Pratul K. Agarwal
- Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee
| | - Matthew J. Cuneo
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee
- Deparment of Structural Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee
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15
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Conservation of Dynamics Associated with Biological Function in an Enzyme Superfamily. Structure 2018; 26:426-436.e3. [PMID: 29478822 DOI: 10.1016/j.str.2018.01.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/06/2017] [Accepted: 01/24/2018] [Indexed: 11/21/2022]
Abstract
Enzyme superfamily members that share common chemical and/or biological functions also share common features. While the role of structure is well characterized, the link between enzyme function and dynamics is not well understood. We present a systematic characterization of intrinsic dynamics of over 20 members of the pancreatic-type RNase superfamily, which share a common structural fold. This study is motivated by the fact that the range of chemical activity as well as molecular motions of RNase homologs spans over 105 folds. Dynamics was characterized using a combination of nuclear magnetic resonance experiments and computer simulations. Phylogenetic clustering led to the grouping of sequences into functionally distinct subfamilies. Detailed characterization of the diverse RNases showed conserved dynamical traits for enzymes within subfamilies. These results suggest that selective pressure for the conservation of dynamical behavior, among other factors, may be linked to the distinct chemical and biological functions in an enzyme superfamily.
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16
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Li L, Ghimire-Rijal S, Lucas SL, Stanley CB, Wright E, Agarwal PK, Myles DA, Cuneo MJ. Periplasmic Binding Protein Dimer Has a Second Allosteric Event Tied to Ligand Binding. Biochemistry 2017; 56:5328-5337. [PMID: 28876049 DOI: 10.1021/acs.biochem.7b00657] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The ligand-induced conformational changes of periplasmic binding proteins (PBP) play a key role in the acquisition of metabolites in ATP binding cassette (ABC) transport systems. This conformational change allows for differential recognition of the ligand occupancy of the PBP by the ABC transporter. This minimizes futile ATP hydrolysis in the transporter, a phenomenon in which ATP hydrolysis is not coupled to metabolite transport. In many systems, the PBP conformational change is insufficient at eliminating futile ATP hydrolysis. Here we identify an additional state of the PBP that is also allosterically regulated by the ligand. Ligand binding to the homodimeric apo PBP leads to a tightening of the interface α-helices so that the hydrogen bonding pattern shifts to that of a 310 helix, in-turn altering the contacts and the dynamics of the protein interface so that the monomer exists in the presence of ligand.
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Affiliation(s)
| | | | - Sarah L Lucas
- Department of Biomedical Engineering, North Carolina State University , Raleigh North Carolina 27607, United States
| | | | - Edward Wright
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Pratul K Agarwal
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
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17
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Norris V, Krylov SN, Agarwal PK, White GJ. Synthetic, Switchable Enzymes. J Mol Microbiol Biotechnol 2017; 27:117-127. [PMID: 28448969 DOI: 10.1159/000464443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The construction of switchable, radiation-controlled, aptameric enzymes - "swenzymes" - is, in principle, feasible. We propose a strategy to make such catalysts from 2 (or more) aptamers each selected to bind specifically to one of the substrates in, for example, a 2-substrate reaction. Construction of a combinatorial library of candidate swenzymes entails selecting a set of a million aptamers that bind one substrate and a second set of a million aptamers that bind the second substrate; the aptamers in these sets are then linked pairwise by a linker, thus bringing together the substrates. In the presence of the substrates, some linked aptamer pairs catalyze the reaction when exposed to external energy in the form of a specific frequency of low-intensity, nonionizing electromagnetic or acoustic radiation. Such swenzymes are detected via a separate product-capturing aptamer that changes conformation on capturing the product; this altered conformation allows it (1) to bind to every potential swenzyme in its vicinity (thereby giving a higher probability of capture to the swenzymes that generate the product) and (2) to bind to a sequence on a magnetic bead (thereby permitting purification of the swenzyme plus product-capturing aptamer by precipitation). Attempts to implement the swenzyme strategy may help elucidate fundamental problems in enzyme catalysis.
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Affiliation(s)
- Vic Norris
- Theoretical Biology Unit, EA 4312, Department of Biology, University of Rouen, Mont Saint Aignan, France
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18
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Kuffel A. How water mediates the long-range interactions between remote protein molecules. Phys Chem Chem Phys 2017; 19:5441-5448. [DOI: 10.1039/c6cp05788h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mechanism of the influence of the presence of one protein molecule on the internal dynamics of another is proposed.
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Affiliation(s)
- Anna Kuffel
- Faculty of Chemistry
- Department of Physical Chemistry
- Gdansk University of Technology
- 80-233 Gdansk
- Poland
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19
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Gagné D, Narayanan C, Nguyen-Thi N, Roux LD, Bernard DN, Brunzelle JS, Couture JF, Agarwal PK, Doucet N. Ligand Binding Enhances Millisecond Conformational Exchange in Xylanase B2 from Streptomyces lividans. Biochemistry 2016; 55:4184-96. [PMID: 27387012 DOI: 10.1021/acs.biochem.6b00130] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Xylanases catalyze the hydrolysis of xylan, an abundant carbon and energy source with important commercial ramifications. Despite tremendous efforts devoted to the catalytic improvement of xylanases, success remains limited because of our relatively poor understanding of their molecular properties. Previous reports suggested the potential role of atomic-scale residue dynamics in modulating the catalytic activity of GH11 xylanases; however, dynamics in these studies was probed on time scales orders of magnitude faster than the catalytic time frame. Here, we used nuclear magnetic resonance titration and relaxation dispersion experiments ((15)N-CPMG) in combination with X-ray crystallography and computational simulations to probe conformational motions occurring on the catalytically relevant millisecond time frame in xylanase B2 (XlnB2) and its catalytically impaired mutant E87A from Streptomyces lividans 66. Our results show distinct dynamical properties for the apo and ligand-bound states of the enzymes. The apo form of XlnB2 experiences conformational exchange for residues in the fingers and palm regions of the catalytic cleft, while the catalytically impaired E87A variant displays millisecond dynamics only in the fingers, demonstrating the long-range effect of the mutation on flexibility. Ligand binding induces enhanced conformational exchange of residues interacting with the ligand in the fingers and thumb loop regions, emphasizing the potential role of residue motions in the fingers and thumb loop regions for recognition, positioning, processivity, and/or stabilization of ligands in XlnB2. To the best of our knowledge, this work represents the first experimental characterization of millisecond dynamics in a GH11 xylanase family member. These results offer new insights into the potential role of conformational exchange in GH11 enzymes, providing essential dynamic information to help improve protein engineering and design applications.
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Affiliation(s)
- Donald Gagné
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada
| | - Chitra Narayanan
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada
| | - Nhung Nguyen-Thi
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada
| | - Louise D Roux
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada
| | - David N Bernard
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada
| | - Joseph S Brunzelle
- Department of Molecular Pharmacology and Biological Chemistry, Feinberg School of Medicine, Northwestern University , 320 East Superior Street, Chicago, Illinois 60611, United States
| | - Jean-François Couture
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa , 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada.,PROTEO, Québec Network for Research on Protein Function, Engineering, and Applications, Université Laval , 1045 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada.,GRASP, Groupe de Recherche Axé sur la Structure des Protéines, McGill University , 3649 Promenade Sir William Osler, Montréal, Québec H3G 0B1, Canada
| | - Pratul K Agarwal
- Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge National Laboratory , 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States.,Department of Biochemistry, Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Nicolas Doucet
- INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada.,PROTEO, Québec Network for Research on Protein Function, Engineering, and Applications, Université Laval , 1045 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada.,GRASP, Groupe de Recherche Axé sur la Structure des Protéines, McGill University , 3649 Promenade Sir William Osler, Montréal, Québec H3G 0B1, Canada
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20
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Agarwal PK, Doucet N, Chennubhotla C, Ramanathan A, Narayanan C. Conformational Sub-states and Populations in Enzyme Catalysis. Methods Enzymol 2016; 578:273-97. [PMID: 27497171 DOI: 10.1016/bs.mie.2016.05.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Enzyme function involves substrate and cofactor binding, precise positioning of reactants in the active site, chemical turnover, and release of products. In addition to formation of crucial structural interactions between enzyme and substrate(s), coordinated motions within the enzyme-substrate complex allow reaction to proceed at a much faster rate, compared to the reaction in solution and in the absence of enzyme. An increasing number of enzyme systems show the presence of conserved protein motions that are important for function. A wide variety of motions are naturally sampled (over femtosecond to millisecond time-scales) as the enzyme complex moves along the energetic landscape, driven by temperature and dynamical events from the surrounding environment. Areas of low energy along the landscape form conformational sub-states, which show higher conformational populations than surrounding areas. A small number of these protein conformational sub-states contain functionally important structural and dynamical features, which assist the enzyme mechanism along the catalytic cycle. Identification and characterization of these higher-energy (also called excited) sub-states and the associated populations are challenging, as these sub-states are very short-lived and therefore rarely populated. Specialized techniques based on computer simulations, theoretical modeling, and nuclear magnetic resonance have been developed for quantitative characterization of these sub-states and populations. This chapter discusses these techniques and provides examples of their applications to enzyme systems.
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Affiliation(s)
- P K Agarwal
- Computational Biology Institute, Oak Ridge National Laboratory, Oak Ridge, TN, United States; University of Tennessee, Knoxville, TN, United States.
| | - N Doucet
- INRS-Institut Armand-Frappier, Université du Québec, Laval, QC, Canada
| | | | - A Ramanathan
- Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - C Narayanan
- INRS-Institut Armand-Frappier, Université du Québec, Laval, QC, Canada
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21
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Fischer AW, Heinze S, Putnam DK, Li B, Pino JC, Xia Y, Lopez CF, Meiler J. CASP11--An Evaluation of a Modular BCL::Fold-Based Protein Structure Prediction Pipeline. PLoS One 2016; 11:e0152517. [PMID: 27046050 PMCID: PMC4821492 DOI: 10.1371/journal.pone.0152517] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 03/15/2016] [Indexed: 11/18/2022] Open
Abstract
In silico prediction of a protein's tertiary structure remains an unsolved problem. The community-wide Critical Assessment of Protein Structure Prediction (CASP) experiment provides a double-blind study to evaluate improvements in protein structure prediction algorithms. We developed a protein structure prediction pipeline employing a three-stage approach, consisting of low-resolution topology search, high-resolution refinement, and molecular dynamics simulation to predict the tertiary structure of proteins from the primary structure alone or including distance restraints either from predicted residue-residue contacts, nuclear magnetic resonance (NMR) nuclear overhauser effect (NOE) experiments, or mass spectroscopy (MS) cross-linking (XL) data. The protein structure prediction pipeline was evaluated in the CASP11 experiment on twenty regular protein targets as well as thirty-three 'assisted' protein targets, which also had distance restraints available. Although the low-resolution topology search module was able to sample models with a global distance test total score (GDT_TS) value greater than 30% for twelve out of twenty proteins, frequently it was not possible to select the most accurate models for refinement, resulting in a general decay of model quality over the course of the prediction pipeline. In this study, we provide a detailed overall analysis, study one target protein in more detail as it travels through the protein structure prediction pipeline, and evaluate the impact of limited experimental data.
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Affiliation(s)
- Axel W. Fischer
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Sten Heinze
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Daniel K. Putnam
- Department of Biomedical Informatics, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Bian Li
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - James C. Pino
- Chemical and Physical Biology Graduate Program, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Yan Xia
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Carlos F. Lopez
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
- Department of Cancer Biology and Center for Quantitative Sciences, Vanderbilt University, Nashville, TN, 37232, United States of America
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, TN, 37232, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, United States of America
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22
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Mei Y, Ramanathan A, Glover K, Stanley C, Sanishvili R, Chakravarthy S, Yang Z, Colbert CL, Sinha SC. Conformational Flexibility Enables the Function of a BECN1 Region Essential for Starvation-Mediated Autophagy. Biochemistry 2016; 55:1945-58. [PMID: 26937551 DOI: 10.1021/acs.biochem.5b01264] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BECN1 is essential for autophagy, a critical eukaryotic cellular homeostasis pathway. Here we delineate a highly conserved BECN1 domain located between previously characterized BH3 and coiled-coil domains and elucidate its structure and role in autophagy. The 2.0 Å sulfur-single-wavelength anomalous dispersion X-ray crystal structure of this domain demonstrates that its N-terminal half is unstructured while its C-terminal half is helical; hence, we name it the flexible helical domain (FHD). Circular dichroism spectroscopy, double electron-electron resonance-electron paramagnetic resonance, and small-angle X-ray scattering (SAXS) analyses confirm that the FHD is partially disordered, even in the context of adjacent BECN1 domains. Molecular dynamic simulations fitted to SAXS data indicate that the FHD transiently samples more helical conformations. FHD helicity increases in 2,2,2-trifluoroethanol, suggesting it may become more helical upon binding. Lastly, cellular studies show that conserved FHD residues are required for starvation-induced autophagy. Thus, the FHD likely undergoes a binding-associated disorder-to-helix transition, and conserved residues critical for this interaction are essential for starvation-induced autophagy.
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Affiliation(s)
- Yang Mei
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Arvind Ramanathan
- Health Data Sciences Institute, Computational Science and Engineering Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
| | - Karen Glover
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Christopher Stanley
- Biology and Soft Matter Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States
| | - Ruslan Sanishvili
- GMCA@APS, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Srinivas Chakravarthy
- Bio-CAT, Advanced Photon Source , 9700 South Cass Avenue, Building 435B, Argonne, Illinois 60439, United States
| | - Zhongyu Yang
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Christopher L Colbert
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
| | - Sangita C Sinha
- Department of Chemistry and Biochemistry, North Dakota State University , Fargo, North Dakota 58108-6050, United States
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23
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Iconaru LI, Ban D, Bharatham K, Ramanathan A, Zhang W, Shelat AA, Zuo J, Kriwacki RW. Discovery of Small Molecules that Inhibit the Disordered Protein, p27(Kip1). Sci Rep 2015; 5:15686. [PMID: 26507530 PMCID: PMC4623604 DOI: 10.1038/srep15686] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 09/25/2015] [Indexed: 01/13/2023] Open
Abstract
Disordered proteins are highly prevalent in biological systems, they control myriad signaling and regulatory processes, and their levels and/or cellular localization are often altered in human disease. In contrast to folded proteins, disordered proteins, due to conformational heterogeneity and dynamics, are not considered viable drug targets. We challenged this paradigm by identifying through NMR-based screening small molecules that bound specifically, albeit weakly, to the disordered cell cycle regulator, p27Kip1 (p27). Two groups of molecules bound to sites created by transient clusters of aromatic residues within p27. Conserved chemical features within these two groups of small molecules exhibited complementarity to their binding sites within p27, establishing structure-activity relationships for small molecule:disordered protein interactions. Finally, one compound counteracted the Cdk2/cyclin A inhibitory function of p27 in vitro, providing proof-of-principle that small molecules can inhibit the function of a disordered protein (p27) through sequestration in a conformation incapable of folding and binding to a natural regulatory target (Cdk2/cyclin A).
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Affiliation(s)
- Luigi I Iconaru
- Department of Structural Biology, Memphis, TN 38105.,Department of Developmental Neurobiology, Memphis, TN 38105
| | - David Ban
- Department of Structural Biology, Memphis, TN 38105
| | - Kavitha Bharatham
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Arvind Ramanathan
- Computational Science and Engineering Division, Health Data Sciences Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37830
| | | | - Anang A Shelat
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Jian Zuo
- Department of Developmental Neurobiology, Memphis, TN 38105
| | - Richard W Kriwacki
- Department of Structural Biology, Memphis, TN 38105.,Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN 38163
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Davis BC, Thorpe IF. Molecular simulations illuminate the role of regulatory components of the RNA polymerase from the hepatitis C virus in influencing protein structure and dynamics. Biochemistry 2013; 52:4541-52. [PMID: 23738897 DOI: 10.1021/bi400251g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The RNA polymerase (gene product NS5B) from the hepatitis C virus is responsible for replication of the viral genome and is a validated drug target for new therapeutic agents. NS5B has a structure resembling an open right hand (containing the fingers, palm, and thumb subdomains), a hydrophobic C-terminal region, and two magnesium ions coordinated in the palm domain. Biochemical data suggest that the magnesium ions provide structural stability and are directly involved in catalysis, while the C-terminus plays a regulatory role in NS5B function. Nevertheless, the molecular mechanisms by which these two features regulate polymerase activity remain unclear. To answer this question, we performed molecular dynamics simulations of NS5B variants with different C-terminal lengths in the presence or absence of magnesium ions to determine the impact on enzyme properties. We observed that metal binding increases both the magnitude and the degree of correlated enzyme motions. In contrast, we observed that the C-terminus restricts enzyme dynamics. Under certain conditions, our simulations revealed a fully closed conformation of NS5B that may facilitate de novo initiation of RNA replication. This knowledge is important because it fosters the development of a comprehensive description of RNA replication by NS5B and is relevant to understanding the functional properties of a broad class of related RNA polymerases such as 3D-pol from poliovirus. Ultimately, this information may also be pertinent to designing novel NS5B therapeutics.
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Affiliation(s)
- Brittny C Davis
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, Baltimore, Maryland 21250, USA
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25
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Rodgers TL, Burnell D, Townsend PD, Pohl E, Cann MJ, Wilson MR, McLeish TCB. ΔΔPT: a comprehensive toolbox for the analysis of protein motion. BMC Bioinformatics 2013; 14:183. [PMID: 23758746 PMCID: PMC3689072 DOI: 10.1186/1471-2105-14-183] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/24/2013] [Indexed: 11/30/2022] Open
Abstract
Background Normal Mode Analysis is one of the most successful techniques for studying motions in proteins and macromolecules. It can provide information on the mechanism of protein functions, used to aid crystallography and NMR data reconstruction, and calculate protein free energies. Results ΔΔPT is a toolbox allowing calculation of elastic network models and principle component analysis. It allows the analysis of pdb files or trajectories taken from; Gromacs, Amber, and DL_POLY. As well as calculation of the normal modes it also allows comparison of the modes with experimental protein motion, variation of modes with mutation or ligand binding, and calculation of molecular dynamic entropies. Conclusions This toolbox makes the respective tools available to a wide community of potential NMA users, and allows them unrivalled ability to analyse normal modes using a variety of techniques and current software.
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Ghosh MC, Ray AK. Membrane phospholipid augments cytochrome P4501a enzymatic activity by modulating structural conformation during detoxification of xenobiotics. PLoS One 2013; 8:e57919. [PMID: 23469105 PMCID: PMC3585281 DOI: 10.1371/journal.pone.0057919] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/27/2013] [Indexed: 12/08/2022] Open
Abstract
Cytochrome P450 is a superfamily of membrane-bound hemoprotein that gets involved with the degradation of xenobiotics and internal metabolites. Accumulated body of evidence indicates that phospholipids play a crucial role in determining the enzymatic activity of cytochrome P450 in the microenvironment by modulating its structure during detoxification; however, the structure-function relationship of cytochrome P4501A, a family of enzymes responsible for degrading lipophilic aromatic hydrocarbons, is still not well defined. Inducibility of cytochrome P4501A in cultured catfish hepatocytes in response to carbofuran, a widely used pesticide around the world, was studied earlier in our laboratory. In this present investigation, we observed that treating catfish with carbofuran augmented total phospholipid in the liver. We examined the role of phospholipid on the of cytochrome P4501A-marker enzyme which is known as ethoxyresorufin-O-deethylase (EROD) in the context of structure and function. We purified the carbofuran-induced cytochrome P4501A protein from catfish liver. Subsequently, we examined the enzymatic activity of purified P4501A protein in the presence of phospholipid, and studied how the structure of purified protein was influenced in the phospholipid environment. Membrane phospholipid appeared to accelerate the enzymatic activity of EROD by changing its structural conformation and thus controlling the detoxification of xenobiotics. Our study revealed the missing link of how the cytochrome P450 restores its enzymatic activity by changing its structural conformation in the phospholipid microenvironment.
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Affiliation(s)
- Manik C Ghosh
- Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America.
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Davis BC, Thorpe IF. Thumb inhibitor binding eliminates functionally important dynamics in the hepatitis C virus RNA polymerase. Proteins 2012; 81:40-52. [PMID: 22855387 DOI: 10.1002/prot.24154] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Revised: 07/12/2012] [Accepted: 07/23/2012] [Indexed: 11/09/2022]
Abstract
Hepatitis C virus (HCV) has infected almost 200 million people worldwide, typically causing chronic liver damage and severe complications such as liver failure. Currently, there are few approved treatments for viral infection. Thus, the HCV RNA-dependent RNA polymerase (gene product NS5B) has emerged as an important target for small molecule therapeutics. Potential therapeutic agents include allosteric inhibitors that bind distal to the enzyme active site. While their mechanism of action is not conclusively known, it has been suggested that certain inhibitors prevent a conformational change in NS5B that is crucial for RNA replication. To gain insight into the molecular origin of long-range allosteric inhibition of NS5B, we employed molecular dynamics simulations of the enzyme with and without an inhibitor bound to the thumb domain. These studies indicate that the presence of an inhibitor in the thumb domain alters both the structure and internal motions of NS5B. Principal components analysis identified motions that are severely attenuated by inhibitor binding. These motions may have functional relevance by facilitating interactions between NS5B and RNA template or nascent RNA duplex, with presence of the ligand leading to enzyme conformations with narrower and thus less accessible RNA binding channels. This study provides the first evidence for a mechanistic basis of allosteric inhibition in NS5B. Moreover, we present evidence that allosteric inhibition of NS5B results from intrinsic features of the enzyme free energy landscape, suggesting a common mechanism for the action of diverse allosteric ligands.
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Affiliation(s)
- Brittny C Davis
- Department of Chemistry and Biochemistry, University of Maryland-Baltimore County, Baltimore, Maryland 21250, USA
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28
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Ramanathan A, Savol AJ, Agarwal PK, Chennubhotla CS. Event detection and sub-state discovery from biomolecular simulations using higher-order statistics: application to enzyme adenylate kinase. Proteins 2012; 80:2536-51. [PMID: 22733562 DOI: 10.1002/prot.24135] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/08/2012] [Accepted: 06/10/2012] [Indexed: 12/25/2022]
Abstract
Biomolecular simulations at millisecond and longer time-scales can provide vital insights into functional mechanisms. Because post-simulation analyses of such large trajectory datasets can be a limiting factor in obtaining biological insights, there is an emerging need to identify key dynamical events and relating these events to the biological function online, that is, as simulations are progressing. Recently, we have introduced a novel computational technique, quasi-anharmonic analysis (QAA) (Ramanathan et al., PLoS One 2011;6:e15827), for partitioning the conformational landscape into a hierarchy of functionally relevant sub-states. The unique capabilities of QAA are enabled by exploiting anharmonicity in the form of fourth-order statistics for characterizing atomic fluctuations. In this article, we extend QAA for analyzing long time-scale simulations online. In particular, we present HOST4MD--a higher-order statistical toolbox for molecular dynamics simulations, which (1) identifies key dynamical events as simulations are in progress, (2) explores potential sub-states, and (3) identifies conformational transitions that enable the protein to access those sub-states. We demonstrate HOST4MD on microsecond timescale simulations of the enzyme adenylate kinase in its apo state. HOST4MD identifies several conformational events in these simulations, revealing how the intrinsic coupling between the three subdomains (LID, CORE, and NMP) changes during the simulations. Further, it also identifies an inherent asymmetry in the opening/closing of the two binding sites. We anticipate that HOST4MD will provide a powerful and extensible framework for detecting biophysically relevant conformational coordinates from long time-scale simulations.
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Affiliation(s)
- Arvind Ramanathan
- Computational Biology Institute & Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
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BURGER VIRGINIAM, RAMANATHAN ARVIND, SAVOL ANDREJJ, STANLEY CHRISTOPHERB, AGARWAL PRATULK, CHENNUBHOTLA CHAKRAS. Quasi-anharmonic analysis reveals intermediate states in the nuclear co-activator receptor binding domain ensemble. PACIFIC SYMPOSIUM ON BIOCOMPUTING. PACIFIC SYMPOSIUM ON BIOCOMPUTING 2012:70-81. [PMID: 22174264 PMCID: PMC6568261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The molten globule nuclear receptor co-activator binding domain (NCBD) of CREB binding protein (CBP) selectively recruits transcription co-activators (TCAs) during the formation of the transcription preinitiation complex. NCBD:TCA interactions have been implicated in several cancers, however, the mechanisms of NCBD:TCA recognition remain uncharacterized. NCBD:TCA intermolecular recognition has challenged traditional investigation as both NCBD and several of its corresponding TCAs are intrinsically disordered. Using 40μs of explicit solvent molecular dynamics simulations, we relate the conformational diversity of ligand-free NCBD to its bound configurations. We introduce two novel techniques to quantify the conformational heterogeneity of ligand-free NCBD, dihedral quasi-anharmonic analysis (dQAA) and hierarchical graph-based diffusive clustering. With this integrated approach we find that three of four ligand-bound states are natively accessible to the ligand-free NCBD simulations with root-mean squared deviation (RMSD) less than 2Å These conformations are accessible via diverse pathways while a rate-limiting barrier must be crossed in order to access the fourth bound state.
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Affiliation(s)
- VIRGINIA M. BURGER
- Joint Carnegie Mellon University-University of Pittsburgh Ph.D. Program in Computational Biology, Oak Ridge, Tennessee 37831, USA
- Department of Computational and Systems Biology, University of Pittsburgh, Pennsylvania 15260, USA
| | - ARVIND RAMANATHAN
- Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge, Tennessee 37831, USA
| | - ANDREJ J. SAVOL
- Joint Carnegie Mellon University-University of Pittsburgh Ph.D. Program in Computational Biology, Oak Ridge, Tennessee 37831, USA
- Department of Computational and Systems Biology, University of Pittsburgh, Pennsylvania 15260, USA
| | - CHRISTOPHER B. STANLEY
- Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - PRATUL K. AGARWAL
- Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge, Tennessee 37831, USA
| | - CHAKRA S. CHENNUBHOTLA
- Department of Computational and Systems Biology, University of Pittsburgh, Pennsylvania 15260, USA
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Kuffel A, Zielkiewicz J. The importance of the shape of the protein–water interface of a kinesin motor domain for dynamics of the surface atoms of the protein. Phys Chem Chem Phys 2012; 14:5561-9. [DOI: 10.1039/c2cp40105c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Evolutionarily conserved linkage between enzyme fold, flexibility, and catalysis. PLoS Biol 2011; 9:e1001193. [PMID: 22087074 PMCID: PMC3210774 DOI: 10.1371/journal.pbio.1001193] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Accepted: 09/27/2011] [Indexed: 11/19/2022] Open
Abstract
Proteins are intrinsically flexible molecules. The role of internal motions in a protein's designated function is widely debated. The role of protein structure in enzyme catalysis is well established, and conservation of structural features provides vital clues to their role in function. Recently, it has been proposed that the protein function may involve multiple conformations: the observed deviations are not random thermodynamic fluctuations; rather, flexibility may be closely linked to protein function, including enzyme catalysis. We hypothesize that the argument of conservation of important structural features can also be extended to identification of protein flexibility in interconnection with enzyme function. Three classes of enzymes (prolyl-peptidyl isomerase, oxidoreductase, and nuclease) that catalyze diverse chemical reactions have been examined using detailed computational modeling. For each class, the identification and characterization of the internal protein motions coupled to the chemical step in enzyme mechanisms in multiple species show identical enzyme conformational fluctuations. In addition to the active-site residues, motions of protein surface loop regions (>10 Å away) are observed to be identical across species, and networks of conserved interactions/residues connect these highly flexible surface regions to the active-site residues that make direct contact with substrates. More interestingly, examination of reaction-coupled motions in non-homologous enzyme systems (with no structural or sequence similarity) that catalyze the same biochemical reaction shows motions that induce remarkably similar changes in the enzyme–substrate interactions during catalysis. The results indicate that the reaction-coupled flexibility is a conserved aspect of the enzyme molecular architecture. Protein motions in distal areas of homologous and non-homologous enzyme systems mediate similar changes in the active-site enzyme–substrate interactions, thereby impacting the mechanism of catalyzed chemistry. These results have implications for understanding the mechanism of allostery, and for protein engineering and drug design.
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Grossman M, Sela-Passwell N, Sagi I. Achieving broad molecular insights into dynamic protein interactions by integrated structural-kinetic approaches. Curr Opin Struct Biol 2011; 21:678-85. [PMID: 21945040 DOI: 10.1016/j.sbi.2011.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 07/21/2011] [Accepted: 07/31/2011] [Indexed: 11/30/2022]
Abstract
A network of dynamic protein interactions with their protein partners, substrates, and ligands is known to be crucial for biological function. Revealing molecular and structural-based mechanisms at atomic resolution and in real-time is fundamental for achieving a basic understanding of cellular processes. These technically challenging goals may be achieved by combining time-resolved spectroscopic and structural-kinetic tools, thus providing broad insights into specific molecular events over a wide range of timescales. Here we review representative studies utilizing such an integrated real-time structural approach designed to reveal molecular mechanisms underlying protein interactions at atomic resolution.
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Affiliation(s)
- Moran Grossman
- Departments of Structural Biology and Biological Regulation, The Weizmann Institute of Science, Rehovot 76100, Israel
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Savol AJ, Burger VM, Agarwal PK, Ramanathan A, Chennubhotla CS. QAARM: quasi-anharmonic autoregressive model reveals molecular recognition pathways in ubiquitin. Bioinformatics 2011; 27:i52-60. [PMID: 21685101 PMCID: PMC3117343 DOI: 10.1093/bioinformatics/btr248] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
MOTIVATION Molecular dynamics (MD) simulations have dramatically improved the atomistic understanding of protein motions, energetics and function. These growing datasets have necessitated a corresponding emphasis on trajectory analysis methods for characterizing simulation data, particularly since functional protein motions and transitions are often rare and/or intricate events. Observing that such events give rise to long-tailed spatial distributions, we recently developed a higher-order statistics based dimensionality reduction method, called quasi-anharmonic analysis (QAA), for identifying biophysically-relevant reaction coordinates and substates within MD simulations. Further characterization of conformation space should consider the temporal dynamics specific to each identified substate. RESULTS Our model uses hierarchical clustering to learn energetically coherent substates and dynamic modes of motion from a 0.5 μs ubiqutin simulation. Autoregressive (AR) modeling within and between states enables a compact and generative description of the conformational landscape as it relates to functional transitions between binding poses. Lacking a predictive component, QAA is extended here within a general AR model appreciative of the trajectory's temporal dependencies and the specific, local dynamics accessible to a protein within identified energy wells. These metastable states and their transition rates are extracted within a QAA-derived subspace using hierarchical Markov clustering to provide parameter sets for the second-order AR model. We show the learned model can be extrapolated to synthesize trajectories of arbitrary length. CONTACT ramanathana@ornl.gov; chakracs@pitt.edu.
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Affiliation(s)
- Andrej J Savol
- Joint Carnegie Mellon University-University of Pittsburgh Ph.D. Program in Computational Biology, Department of Computational and Systems Biology, University of Pittsburgh, PA 15260, USA
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34
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Borreguero JM, He J, Meilleur F, Weiss KL, Brown CM, Myles DA, Herwig KW, Agarwal PK. Redox-promoting protein motions in rubredoxin. J Phys Chem B 2011; 115:8925-36. [PMID: 21608980 DOI: 10.1021/jp201346x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proteins are dynamic objects, constantly undergoing conformational fluctuations, yet the linkage between internal protein motion and function is widely debated. This study reports on the characterization of temperature-activated collective and individual atomic motions of oxidized rubredoxin, a small 53 residue protein from thermophilic Pyrococcus furiosus (RdPf). Computational modeling allows detailed investigations of protein motions as a function of temperature, and neutron scattering experiments are used to compare to computational results. Just above the dynamical transition temperature which marks the onset of significant anharmonic motions of the protein, the computational simulations show both a significant reorientation of the average electrostatic force experienced by the coordinated Fe(3+) ion and a dramatic rise in its strength. At higher temperatures, additional anharmonic modes become activated and dominate the electrostatic fluctuations experienced by the ion. At 360 K, close to the optimal growth temperature of P. furiosus, simulations show that three anharmonic modes including motions of two conserved residues located at the protein active site (Ile7 and Ile40) give rise to the majority of the electrostatic fluctuations experienced by the Fe(3+) ion. The motions of these residues undergo displacements which may facilitate solvent access to the ion.
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Affiliation(s)
- Jose M Borreguero
- Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States.
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35
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Wavelet transform analysis of NMR structure ensembles to reveal internal fluctuations of enzymes. Amino Acids 2011; 42:1773-81. [PMID: 21479702 DOI: 10.1007/s00726-011-0895-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 03/21/2011] [Indexed: 10/18/2022]
Abstract
Internal motions and flexibility are essential for biological functions in proteins. To assess the internal fluctuations and conformational flexibility of proteins, reliable computational methods are needed. In this study, wavelet transformation was used to filter out the noise and facilitate investigating the internal positional fluctuations of enzymes within nuclear magnetic resonance (NMR) structure ensembles. Moreover, potential active sites were identified by combining with positional fluctuation score, sequence conservation, and solvent accessible surface area. Among the total 107 catalytic residues in 44 examined enzymes, 69 residues were identified correctly. Our results suggest that wavelet transform analysis of structure ensemble is applicable to extract essential fluctuation information of proteins; furthermore, analysis of positional fluctuations is helpful for the identification of catalytic residues.
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36
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Huang KY, Amodeo GA, Tong L, McDermott A. The structure of human ubiquitin in 2-methyl-2,4-pentanediol: a new conformational switch. Protein Sci 2011; 20:630-9. [PMID: 21432937 PMCID: PMC3064841 DOI: 10.1002/pro.584] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A new crystal structure of human ubiquitin is reported at 1.8 Å resolution. Compared with the other known crystal structure or the solution NMR structure of monomeric human ubiquitin, this new structure is similar in its overall fold but differs with respect to the conformation of the backbone in a surface-exposed region. The conformation reported here resembles conformations previously seen in complex with deubiquinating enzymes, wherein the Asp52/Gly53 main chain and Glu24 side chain move. This movement exposes the backbone carbonyl of Asp52 to the exterior of the molecule, making it possible to engage in hydrogen-bond contacts with neighboring molecules, rather than in an internal hydrogen bond with the backbone of Glu24. This particular crystal form of ubiquitin has been used in a large number of solid state NMR studies. The structure described here elucidates the origin of many of the chemical shift differences comparing solution and solid state studies.
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Affiliation(s)
- Kuo Ying Huang
- Department of Chemistry, Columbia UniversityNew York, New York 10027
| | - Gabriele A Amodeo
- Department of Biological Science, Columbia UniversityNew York, New York 10027
| | - Liang Tong
- Department of Biological Science, Columbia UniversityNew York, New York 10027
| | - Ann McDermott
- Department of Chemistry, Columbia UniversityNew York, New York 10027,*Correspondence to: Ann McDermott, Columbia University, Department of Chemistry, MC3113, New York, NY 10027. E-mail:
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Ramanathan A, Yoo JO, Langmead CJ. On-the-Fly Identification of Conformational Substates from Molecular Dynamics Simulations. J Chem Theory Comput 2011; 7:778-89. [DOI: 10.1021/ct100531j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Arvind Ramanathan
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Ji Oh Yoo
- Computer Science Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Christopher J. Langmead
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
- Computer Science Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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Ramanathan A, Savol AJ, Langmead CJ, Agarwal PK, Chennubhotla CS. Discovering conformational sub-states relevant to protein function. PLoS One 2011; 6:e15827. [PMID: 21297978 PMCID: PMC3030567 DOI: 10.1371/journal.pone.0015827] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 11/25/2010] [Indexed: 11/23/2022] Open
Abstract
Background Internal motions enable proteins to explore a range of conformations, even in the vicinity of native state. The role of conformational fluctuations in the designated function of a protein is widely debated. Emerging evidence suggests that sub-groups within the range of conformations (or sub-states) contain properties that may be functionally relevant. However, low populations in these sub-states and the transient nature of conformational transitions between these sub-states present significant challenges for their identification and characterization. Methods and Findings To overcome these challenges we have developed a new computational technique, quasi-anharmonic analysis (QAA). QAA utilizes higher-order statistics of protein motions to identify sub-states in the conformational landscape. Further, the focus on anharmonicity allows identification of conformational fluctuations that enable transitions between sub-states. QAA applied to equilibrium simulations of human ubiquitin and T4 lysozyme reveals functionally relevant sub-states and protein motions involved in molecular recognition. In combination with a reaction pathway sampling method, QAA characterizes conformational sub-states associated with cis/trans peptidyl-prolyl isomerization catalyzed by the enzyme cyclophilin A. In these three proteins, QAA allows identification of conformational sub-states, with critical structural and dynamical features relevant to protein function. Conclusions Overall, QAA provides a novel framework to intuitively understand the biophysical basis of conformational diversity and its relevance to protein function.
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Affiliation(s)
- Arvind Ramanathan
- Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- Lane Center for Computational Biology, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Andrej J. Savol
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Joint Carnegie Mellon University–University of Pittsburgh Ph.D. Program in Computational Biology, Pittsburgh, Pennsylvania, United States of America
| | - Christopher J. Langmead
- Computer Science Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- Lane Center for Computational Biology, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Pratul K. Agarwal
- Computational Biology Institute and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America
- * E-mail: (PKA); (CSC)
| | - Chakra S. Chennubhotla
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (PKA); (CSC)
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Dykeman EC, Sankey OF. Normal mode analysis and applications in biological physics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:423202. [PMID: 21403307 DOI: 10.1088/0953-8984/22/42/423202] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Normal mode analysis has become a popular and often used theoretical tool in the study of functional motions in enzymes, viruses, and large protein assemblies. The use of normal modes in the study of these motions is often extremely fruitful since many of the functional motions of large proteins can be described using just a few normal modes which are intimately related to the overall structure of the protein. In this review, we present a broad overview of several popular methods used in the study of normal modes in biological physics including continuum elastic theory, the elastic network model, and a new all-atom method, recently developed, which is capable of computing a subset of the low frequency vibrational modes exactly. After a review of the various methods, we present several examples of applications of normal modes in the study of functional motions, with an emphasis on viral capsids.
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Affiliation(s)
- Eric C Dykeman
- Department of Physics, Center for Biological Physics, Arizona State University, Tempe, AZ 85287-1504, USA
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