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Zhang X, Luo Y, Hao H, Krahn JM, Su G, Dutcher R, Xu Y, Liu J, Pedersen LC, Xu D. Heparan sulfate selectively inhibits the collagenase activity of cathepsin K. Matrix Biol 2024; 129:S0945-053X(24)00050-7. [PMID: 38548090 DOI: 10.1016/j.matbio.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/09/2024]
Abstract
Cathepsin K (CtsK) is a cysteine protease with potent collagenase activity. CtsK is highly expressed by bone-resorbing osteoclasts and plays an essential role in resorption of bone matrix. Although CtsK is known to bind heparan sulfate (HS), the structural details of the interaction, and how HS regulates the biological functions of CtsK, remains largely unknown. In this report, we discovered that HS is a multifaceted regulator of the structure and function of CtsK. Structurally, HS forms a highly stable complex with CtsK and induces its dimerization. Co-crystal structures of CtsK with bound HS oligosaccharides reveal the location of the HS binding site and suggest how HS may support dimerization. Functionally, HS plays a dual role in regulating the enzymatic activity of CtsK. While it preserves the peptidase activity of CtsK by stabilizing its active conformation, it inhibits the collagenase activity of CtsK in a sulfation level-dependent manner. These opposing effects can be explained by our finding that the HS binding site is remote from the active site, which allows HS to specifically inhibit the collagenase activity without affecting the peptidase activity. At last, we show that structurally defined HS oligosaccharides effectively block osteoclast resorption of bone in vitro without inhibiting osteoclast differentiation, which suggests that HS-based oligosaccharide might be explored as a new class of selective CtsK inhibitor for many diseases involving exaggerated bone resorption.
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Affiliation(s)
- Xiaoxiao Zhang
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
| | - Yin Luo
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
| | - Huanmeng Hao
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
| | - Juno M Krahn
- Macromolecular Structure Group, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Guowei Su
- Glycan Therapeutics Corp, 617 Hutton Street, Raleigh, NC 27606
| | - Robert Dutcher
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yongmei Xu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lars C Pedersen
- Macromolecular Structure Group, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Ding Xu
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.
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2
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Hayne CK, Butay KJU, Stewart ZD, Krahn JM, Perera L, Williams JG, Petrovitch RM, Deterding LJ, Matera AG, Borgnia MJ, Stanley RE. Author Correction: Structural basis for pre-tRNA recognition and processing by the human tRNA splicing endonuclease complex. Nat Struct Mol Biol 2024; 31:390. [PMID: 38196035 DOI: 10.1038/s41594-024-01213-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Affiliation(s)
- Cassandra K Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA.
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
| | - Kevin John U Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
- Georgetown University, Washington, DC, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Robert M Petrovitch
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, Departments of Biology and Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA.
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3
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Zhang X, Luo Y, Hao H, Krahn JM, Su G, Dutcher R, Xu Y, Liu J, Pedersen LC, Xu D. Heparan sulfate selectively inhibits the collagenase activity of cathepsin K. bioRxiv 2024:2024.01.05.574350. [PMID: 38260317 PMCID: PMC10802503 DOI: 10.1101/2024.01.05.574350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cathepsin K (CtsK) is a cysteine protease with potent collagenase activity. CtsK is highly expressed by bone-resorbing osteoclasts and plays an essential role in bone remodeling. Although CtsK is known to bind heparan sulfate (HS), the structural details of the interaction, and how HS ultimately regulates the biological functions of CtsK, remains largely unknown. In this report, we determined that CtsK preferably binds to larger HS oligosaccharides, such as dodecasaccharides (12mer), and that the12mer can induce monomeric CtsK to form a stable dimer in solution. Interestingly, while HS has no effect on the peptidase activity of CtsK, it greatly inhibits the collagenase activity of CtsK in a manner dependent on sulfation level. By forming a complex with CtsK, HS was able to preserve the full peptidase activity of CtsK for prolonged periods, likely by stabilizing its active conformation. Crystal structures of Ctsk with a bound 12mer, alone and in the presence of the endogenous inhibitor cystatin-C reveal the location of HS binding is remote from the active site. Mutagenesis based on these complex structures identified 6 basic residues of Ctsk that play essential roles in mediating HS-binding. At last, we show that HS 12mers can effectively block osteoclast resorption of bone in vitro. Combined, we have shown that HS can function as a multifaceted regulator of CtsK and that HS-based oligosaccharide might be explored as a new class of selective CtsK inhibitor in many diseases that involve exaggerated bone resorption.
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Affiliation(s)
- Xiaoxiao Zhang
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
| | - Yin Luo
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
- These authors contributed equally to this work
| | - Huanmeng Hao
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
- These authors contributed equally to this work
| | - Juno M. Krahn
- Macromolecular Structure Group, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Guowei Su
- Glycan Therapeutics Corp, 617 Hutton Street, Raleigh, NC 27606
| | - Robert Dutcher
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Yongmei Xu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lars C. Pedersen
- Macromolecular Structure Group, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Ding Xu
- Department of Oral Biology, School of Dental Medicine, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA
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4
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Kirby TW, Gabel SA, DeRose EF, Perera L, Krahn JM, Pedersen LC, London RE. Targeting the Structural Maturation Pathway of HIV-1 Reverse Transcriptase. Biomolecules 2023; 13:1603. [PMID: 38002285 PMCID: PMC10669680 DOI: 10.3390/biom13111603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/19/2023] [Accepted: 10/26/2023] [Indexed: 11/26/2023] Open
Abstract
Formation of active HIV-1 reverse transcriptase (RT) proceeds via a structural maturation process that involves subdomain rearrangements and formation of an asymmetric p66/p66' homodimer. These studies were undertaken to evaluate whether the information about this maturation process can be used to identify small molecule ligands that retard or interfere with the steps involved. We utilized the isolated polymerase domain, p51, rather than p66, since the initial subdomain rearrangements are largely limited to this domain. Target sites at subdomain interfaces were identified and computational analysis used to obtain an initial set of ligands for screening. Chromatographic evaluations of the p51 homodimer/monomer ratio support the feasibility of this approach. Ligands that bind near the interfaces and a ligand that binds directly to a region of the fingers subdomain involved in subunit interface formation were identified, and the interactions were further characterized by NMR spectroscopy and X-ray crystallography. Although these ligands were found to reduce dimer formation, further efforts will be required to obtain ligands with higher binding affinity. In contrast with previous ligand identification studies performed on the RT heterodimer, subunit interface surfaces are solvent-accessible in the p51 and p66 monomers, making these constructs preferable for identification of ligands that directly interfere with dimerization.
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Affiliation(s)
| | | | | | | | | | | | - Robert E. London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, Durham, NC 27709, USA (J.M.K.)
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5
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Appel CD, Bermek O, Dandey VP, Wood M, Viverette E, Williams JG, Bouvette J, Riccio AA, Krahn JM, Borgnia MJ, Williams RS. Sen1 architecture: RNA-DNA hybrid resolution, autoregulation, and insights into SETX inactivation in AOA2. Mol Cell 2023; 83:3692-3706.e5. [PMID: 37832548 PMCID: PMC10629462 DOI: 10.1016/j.molcel.2023.09.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 07/25/2023] [Accepted: 09/20/2023] [Indexed: 10/15/2023]
Abstract
The senataxin (SETX, Sen1 in yeasts) RNA-DNA hybrid resolving helicase regulates multiple nuclear transactions, including DNA replication, transcription, and DNA repair, but the molecular basis for Sen1 activities is ill defined. Here, Sen1 cryoelectron microscopy (cryo-EM) reconstructions reveal an elongated inchworm-like architecture. Sen1 is composed of an amino terminal helical repeat Sen1 N-terminal (Sen1N) regulatory domain that is flexibly linked to its C-terminal SF1B helicase motor core (Sen1Hel) via an intrinsically disordered tether. In an autoinhibited state, the Sen1Sen1N domain regulates substrate engagement by promoting occlusion of the RNA substrate-binding cleft. The X-ray structure of an activated Sen1Hel engaging single-stranded RNA and ADP-SO4 shows that the enzyme encircles RNA and implicates a single-nucleotide power stroke in the Sen1 RNA translocation mechanism. Together, our data unveil dynamic protein-protein and protein-RNA interfaces underpinning helicase regulation and inactivation of human SETX activity by RNA-binding-deficient mutants in ataxia with oculomotor apraxia 2 neurodegenerative disease.
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Affiliation(s)
- C Denise Appel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Oya Bermek
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Venkata P Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Makayla Wood
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Elizabeth Viverette
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jonathan Bouvette
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Amanda A Riccio
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - R Scott Williams
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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6
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Brehm W, Triviño J, Krahn JM, Usón I, Diederichs K. XDSGUI: a graphical user interface for XDS, SHELX and ARCIMBOLDO. J Appl Crystallogr 2023; 56:1585-1594. [PMID: 37791359 PMCID: PMC10543682 DOI: 10.1107/s1600576723007057] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/08/2023] [Indexed: 10/05/2023] Open
Abstract
XDSGUI is a lightweight graphical user interface (GUI) for the XDS, SHELX and ARCIMBOLDO program packages that serves both novice and experienced users in obtaining optimal processing and phasing results for X-ray, neutron and electron diffraction data. The design of the program enables data processing and phasing without command line usage, and supports advanced command flows in a simple user-modifiable and user-extensible way. The GUI supplies graphical information based on the tabular log output of the programs, which is more intuitive, comprehensible and efficient than text output can be.
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Affiliation(s)
- Wolfgang Brehm
- Department of Physics, University of Hamburg, Hamburg 22761, Germany
| | - Josep Triviño
- Instituto de Biologia Molecular de Barcelona (IBMB), Baldiri Reixach 15, Barcelona 08028, Spain
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Isabel Usón
- Instituto de Biologia Molecular de Barcelona (IBMB), Baldiri Reixach 15, Barcelona 08028, Spain
- ICREA: Institució Catalana de Recerca i Estudis Avançats, Pg. Lluis Companys 23, Barcelona 08010, Spain
| | - Kay Diederichs
- Department of Biology, University of Konstanz, Universitätsstrasse, Konstanz 78457, Germany
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7
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Hayne CK, Butay KJU, Stewart ZD, Krahn JM, Perera L, Williams JG, Petrovitch RM, Deterding LJ, Matera AG, Borgnia MJ, Stanley RE. Structural basis for pre-tRNA recognition and processing by the human tRNA splicing endonuclease complex. Nat Struct Mol Biol 2023; 30:824-833. [PMID: 37231153 PMCID: PMC10627149 DOI: 10.1038/s41594-023-00991-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 04/06/2023] [Indexed: 05/27/2023]
Abstract
Throughout bacteria, archaea and eukarya, certain tRNA transcripts contain introns. Pre-tRNAs with introns require splicing to form the mature anticodon stem loop. In eukaryotes, tRNA splicing is initiated by the heterotetrameric tRNA splicing endonuclease (TSEN) complex. All TSEN subunits are essential, and mutations within the complex are associated with a family of neurodevelopmental disorders known as pontocerebellar hypoplasia (PCH). Here, we report cryo-electron microscopy structures of the human TSEN-pre-tRNA complex. These structures reveal the overall architecture of the complex and the extensive tRNA binding interfaces. The structures share homology with archaeal TSENs but contain additional features important for pre-tRNA recognition. The TSEN54 subunit functions as a pivotal scaffold for the pre-tRNA and the two endonuclease subunits. Finally, the TSEN structures enable visualization of the molecular environments of PCH-causing missense mutations, providing insight into the mechanism of pre-tRNA splicing and PCH.
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Affiliation(s)
- Cassandra K Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA.
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA.
| | - Kevin John U Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
- Georgetown University, Washington, DC, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Robert M Petrovitch
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, Departments of Biology and Genetics, University of North Carolina, Chapel Hill, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA.
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8
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Klemm BP, Singh D, Smith CE, Hsu AL, Dillard LB, Krahn JM, London RE, Mueller GA, Borgnia MJ, Schaaper RM. Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase. Proc Natl Acad Sci U S A 2022; 119:e2123092119. [PMID: 36067314 PMCID: PMC9478638 DOI: 10.1073/pnas.2123092119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 08/09/2022] [Indexed: 11/18/2022] Open
Abstract
Levels of the cellular dNTPs, the direct precursors for DNA synthesis, are important for DNA replication fidelity, cell cycle control, and resistance against viruses. Escherichia coli encodes a dGTPase (2'-deoxyguanosine-5'-triphosphate [dGTP] triphosphohydrolase [dGTPase]; dgt gene, Dgt) that establishes the normal dGTP level required for accurate DNA replication but also plays a role in protecting E. coli against bacteriophage T7 infection by limiting the dGTP required for viral DNA replication. T7 counteracts Dgt using an inhibitor, the gene 1.2 product (Gp1.2). This interaction is a useful model system for studying the ongoing evolutionary virus/host "arms race." We determined the structure of Gp1.2 by NMR spectroscopy and solved high-resolution cryo-electron microscopy structures of the Dgt-Gp1.2 complex also including either dGTP substrate or GTP coinhibitor bound in the active site. These structures reveal the mechanism by which Gp1.2 inhibits Dgt and indicate that Gp1.2 preferentially binds the GTP-bound form of Dgt. Biochemical assays reveal that the two inhibitors use different modes of inhibition and bind to Dgt in combination to yield enhanced inhibition. We thus propose an in vivo inhibition model wherein the Dgt-Gp1.2 complex equilibrates with GTP to fully inactivate Dgt, limiting dGTP hydrolysis and preserving the dGTP pool for viral DNA replication.
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Affiliation(s)
- Bradley P. Klemm
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Deepa Singh
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Cassandra E. Smith
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Allen L. Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Lucas B. Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Robert E. London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Geoffrey A. Mueller
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
| | - Roel M. Schaaper
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709
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9
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Riccio AA, Bouvette J, Longley MJ, Krahn JM, Borgnia MJ, Copeland WC. Method for the structural analysis of Twinkle mitochondrial DNA helicase by cryo-EM. Methods 2022; 205:263-270. [PMID: 35779765 PMCID: PMC9398961 DOI: 10.1016/j.ymeth.2022.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 12/13/2022] Open
Abstract
The mitochondrial replisome replicates the 16.6 kb mitochondria DNA (mtDNA). The proper functioning of this multicomponent protein complex is vital for the integrity of the mitochondrial genome. One of the critical protein components of the mitochondrial replisome is the Twinkle helicase, a member of the Superfamily 4 (SF4) helicases. Decades of research has uncovered common themes among SF4 helicases including self-assembly, ATP-dependent translocation, and formation of protein-protein complexes. Some of the molecular details of these processes are still unknown for the mitochondria SF4 helicase, Twinkle. Here, we describe a protocol for expression, purification, and single-particle cryo-electron microscopy of the Twinkle helicase clinical variant, W315L, which resulted in the first high-resolution structure of Twinkle helicase. The methods described here serve as an adaptable protocol to support future high-resolution studies of Twinkle helicase or other SF4 helicases.
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Affiliation(s)
- Amanda A Riccio
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Jonathan Bouvette
- Molecular Microscopy Consortium, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Matthew J Longley
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Molecular Microscopy Consortium, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - William C Copeland
- Mitochondrial DNA Replication Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
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10
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Kocaman S, Lo YH, Krahn JM, Sobhany M, Dandey VP, Petrovich ML, Etigunta SK, Williams JG, Deterding LJ, Borgnia MJ, Stanley RE. Communication network within the essential AAA-ATPase Rix7 drives ribosome assembly. PNAS Nexus 2022; 1:pgac118. [PMID: 36090660 PMCID: PMC9437592 DOI: 10.1093/pnasnexus/pgac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/08/2022] [Indexed: 02/06/2023]
Abstract
Rix7 is an essential AAA+ ATPase that functions during the early stages of ribosome biogenesis. Rix7 is composed of three domains including an N-terminal domain (NTD) and two AAA+ domains (D1 and D2) that assemble into an asymmetric stacked hexamer. It was recently established that Rix7 is a presumed protein translocase that removes substrates from preribosomes by translocating them through its central pore. However, how the different domains of Rix7 coordinate their activities within the overall hexameric structure was unknown. We captured cryo-electron microscopy (EM) structures of single and double Walker B variants of full length Rix7. The disordered NTD was not visible in the cryo-EM reconstructions, but cross-linking mass spectrometry revealed that the NTD can associate with the central channel in vitro. Deletion of the disordered NTD enabled us to obtain a structure of the Rix7 hexamer to 2.9 Å resolution, providing high resolution details of critical motifs involved in substrate translocation and interdomain communication. This structure coupled with cell-based assays established that the linker connecting the D1 and D2 domains as well as the pore loops lining the central channel are essential for formation of the large ribosomal subunit. Together, our work shows that Rix7 utilizes a complex communication network to drive ribosome biogenesis.
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Affiliation(s)
- Seda Kocaman
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Venkata P Dandey
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Matthew L Petrovich
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Suhas K Etigunta
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J Deterding
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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11
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Frazier MN, Wilson IM, Krahn JM, Butay KJ, Dillard LB, Borgnia MJ, Stanley RE. Flipped over U: structural basis for dsRNA cleavage by the SARS-CoV-2 endoribonuclease. Nucleic Acids Res 2022; 50:8290-8301. [PMID: 35801916 DOI: 10.1093/nar/gkac589] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/23/2022] [Accepted: 06/24/2022] [Indexed: 01/13/2023] Open
Abstract
Coronaviruses generate double-stranded (ds) RNA intermediates during viral replication that can activate host immune sensors. To evade activation of the host pattern recognition receptor MDA5, coronaviruses employ Nsp15, which is a uridine-specific endoribonuclease. Nsp15 is proposed to associate with the coronavirus replication-transcription complex within double-membrane vesicles to cleave these dsRNA intermediates. How Nsp15 recognizes and processes dsRNA is poorly understood because previous structural studies of Nsp15 have been limited to small single-stranded (ss) RNA substrates. Here we present cryo-EM structures of SARS-CoV-2 Nsp15 bound to a 52nt dsRNA. We observed that the Nsp15 hexamer forms a platform for engaging dsRNA across multiple protomers. The structures, along with site-directed mutagenesis and RNA cleavage assays revealed critical insight into dsRNA recognition and processing. To process dsRNA Nsp15 utilizes a base-flipping mechanism to properly orient the uridine within the active site for cleavage. Our findings show that Nsp15 is a distinctive endoribonuclease that can cleave both ss- and dsRNA effectively.
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Affiliation(s)
- Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Isha M Wilson
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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12
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Frazier MN, Wilson IM, Krahn JM, Butay KJ, Dillard LB, Borgnia MJ, Stanley RE. Flipped Over U: Structural Basis for dsRNA Cleavage by the SARS-CoV-2 Endoribonuclease. bioRxiv 2022:2022.03.02.480688. [PMID: 35262076 PMCID: PMC8902873 DOI: 10.1101/2022.03.02.480688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Coronaviruses generate double-stranded (ds) RNA intermediates during viral replication that can activate host immune sensors. To evade activation of the host pattern recognition receptor MDA5, coronaviruses employ Nsp15, which is uridine-specific endoribonuclease. Nsp15 is proposed to associate with the coronavirus replication-transcription complex within double-membrane vesicles to cleave these dsRNA intermediates. How Nsp15 recognizes and processes dsRNA is poorly understood because previous structural studies of Nsp15 have been limited to small single-stranded (ss) RNA substrates. Here we present cryo-EM structures of SARS-CoV-2 Nsp15 bound to a 52nt dsRNA. We observed that the Nsp15 hexamer forms a platform for engaging dsRNA across multiple protomers. The structures, along with site-directed mutagenesis and RNA cleavage assays revealed critical insight into dsRNA recognition and processing. To process dsRNA Nsp15 utilizes a base-flipping mechanism to properly orient the uridine within the active site for cleavage. Our findings show that Nsp15 is a distinctive endoribonuclease that can cleave both ss- and dsRNA effectively.
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Affiliation(s)
- Meredith N. Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Isha M. Wilson
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B. Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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13
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Nodzenski M, Shi M, Krahn JM, Wise AS, Li Y, Li L, Umbach DM, Weinberg CR. GADGETS: a genetic algorithm for detecting epistasis using nuclear families. Bioinformatics 2022; 38:1052-1058. [PMID: 34788792 PMCID: PMC10060691 DOI: 10.1093/bioinformatics/btab766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 10/08/2021] [Accepted: 11/03/2021] [Indexed: 02/03/2023] Open
Abstract
MOTIVATION Epistasis may play an etiologic role in complex diseases, but research has been hindered because identification of interactions among sets of single nucleotide polymorphisms (SNPs) requires exploration of immense search spaces. Current approaches using nuclear families accommodate at most several hundred candidate SNPs. RESULTS GADGETS detects epistatic SNP-sets by applying a genetic algorithm to case-parent or case-sibling data. To allow for multiple epistatic sets, island subpopulations of SNP-sets evolve separately under selection for evident joint relevance to disease risk. The software evaluates the identified SNP-sets via permutation testing and provides graphical visualization. GADGETS correctly identified epistatic SNP-sets in realistically simulated case-parent triads with 10 000 candidate SNPs, far more SNPs than competitors can handle, and it outperformed competitors in simulations with many fewer SNPs. Applying GADGETS to family-based oral-clefting data from dbGaP identified SNP-sets with possible epistatic effects on risk. AVAILABILITY AND IMPLEMENTATION GADGETS is part of the epistasisGA package at https://github.com/mnodzenski/epistasisGA. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Michael Nodzenski
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Min Shi
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Alison S Wise
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Yuanyuan Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - David M Umbach
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Clarice R Weinberg
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
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14
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Nodzenski M, Shi M, Krahn JM, Wise AS, Li Y, Li L, Umbach DM, Weinberg CR. Erratum to: GADGETS: a genetic algorithm for detecting epistasis using nuclear families. Bioinformatics 2022; 38:881. [PMID: 34950948 PMCID: PMC11020212 DOI: 10.1093/bioinformatics/btab833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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15
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Wander R, Kaminski AM, Wang Z, Stancanelli E, Xu Y, Pagadala V, Li J, Krahn JM, Pham TQ, Liu J, Pedersen LC. Structural and substrate specificity analysis of 3- O-sulfotransferase isoform 5 to synthesize heparan sulfate. ACS Catal 2021; 11:14956-14966. [PMID: 35223137 PMCID: PMC8865405 DOI: 10.1021/acscatal.1c04520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Heparan sulfate 3-O-sulfotransferase (3-OST) transfers a sulfo group to the 3-OH position of a glucosamine saccharide unit to form 3-O-sulfated heparan sulfate. 3-O-sulfation is known to be critically important for bestowing anticoagulant activity and other biological functions of heparan sulfate. Here, we report two ternary crystal structures of 3-OST-5 with PAP (3'-phosphoadenosine 5'-phosphate) and two octasaccharide substrates. We also used 3-OST-5 to synthesize six 3-O-sulfated 8-mers. Results from the structural analysis of the six 3-O-sulfated 8-mers revealed the substrate specificity of 3-OST-5. The enzyme prefers to sulfate a 6-O-sulfo glucosamine saccharide that is surrounded by glucuronic acid over a 6-O-sulfo glucosamine saccharide that is surrounded by 2-O-sulfated iduronic acid. 3-OST-5 modified 8-mers display a broad range of anti-factor Xa activity, depending on the structure of the 8-mer. We also discovered that the substrate specificity of 3-OST-5 is not governed solely by the side chains from amino acid residues in the active site. The conformational flexibility of the 2-O-sulfated iduronic acid in the saccharide substrates also contributes to the substrate specificity. These findings advance our understanding for how to control the biosynthesis of 3-O-sulfated heparan sulfate with desired biological activities.
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Affiliation(s)
- Rylee Wander
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Andrea M. Kaminski
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Zhangjie Wang
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Eduardo Stancanelli
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Yongmei Xu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | | | - Jine Li
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
| | - Truong Quang Pham
- Glycan Therapeutics Corp, 617 Hutton Street, Raleigh, North Carolina, USA
| | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lars C. Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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16
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Frazier MN, Dillard LB, Krahn JM, Perera L, Williams JG, Wilson IM, Stewart ZD, Pillon MC, Deterding LJ, Borgnia MJ, Stanley RE. Characterization of SARS2 Nsp15 nuclease activity reveals it's mad about U. Nucleic Acids Res 2021; 49:10136-10149. [PMID: 34403466 PMCID: PMC8385992 DOI: 10.1093/nar/gkab719] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/04/2021] [Accepted: 08/09/2021] [Indexed: 12/18/2022] Open
Abstract
Nsp15 is a uridine specific endoribonuclease that coronaviruses employ to cleave viral RNA and evade host immune defense systems. Previous structures of Nsp15 from across Coronaviridae revealed that Nsp15 assembles into a homo-hexamer and has a conserved active site similar to RNase A. Beyond a preference for cleaving RNA 3′ of uridines, it is unknown if Nsp15 has any additional substrate preferences. Here, we used cryo-EM to capture structures of Nsp15 bound to RNA in pre- and post-cleavage states. The structures along with molecular dynamics and biochemical assays revealed critical residues involved in substrate specificity, nuclease activity, and oligomerization. Moreover, we determined how the sequence of the RNA substrate dictates cleavage and found that outside of polyU tracts, Nsp15 has a strong preference for purines 3′ of the cleaved uridine. This work advances our understanding of how Nsp15 recognizes and processes viral RNA, and will aid in the development of new anti-viral therapeutics.
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Affiliation(s)
- Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Isha M Wilson
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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17
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Wander R, Kaminski AM, Xu Y, Pagadala V, Krahn JM, Pham TQ, Liu J, Pedersen LC. Deciphering the substrate recognition mechanisms of the heparan sulfate 3- O-sulfotransferase-3. RSC Chem Biol 2021; 2:1239-1248. [PMID: 34458837 PMCID: PMC8341778 DOI: 10.1039/d1cb00079a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 05/28/2021] [Indexed: 02/01/2023] Open
Abstract
The sulfation at the 3-OH position of a glucosamine saccharide is a rare modification, but is critically important for the biological activities of heparan sulfate polysaccharides. Heparan sulfate 3-O-sulfotransferase (3-OST), the enzyme responsible for completing this modification, is present in seven different isoforms in humans. Individual isoforms display substrate selectivity to uniquely sulfated saccharide sequences present in heparan sulfate polysaccharides. Here, we report two ternary crystal structures of heparan sulfate 3-OST isoform 3 (3-OST-3) with PAP (3'-phosphoadenosine 5'-phosphate) and two octasaccharide substrates: non 6-O-sulfated octasaccharide (8-mer 1) and 6-O-sulfated octasaccharide (8-mer 3). The 8-mer 1 is a known favorable substrate for 3-OST-3, whereas the 8-mer 3 is an unfavorable one. Unlike the 8-mer 1, we discovered that the 8-mer 3 displays two binding orientations to the enzyme: productive binding and non-productive binding. Results from the enzyme activity studies demonstrate that 8-mer 3 can contribute to either substrate or product inhibition, possibly attributed to a non-productive binding mode. Our results suggest that heparan sulfate substrates interact with the 3-OST-3 enzyme in more than one orientation, which may regulate the activity of the enzyme. Our findings also suggest that different binding orientations between polysaccharides and their protein binding partners could influence biological outcomes.
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Affiliation(s)
- Rylee Wander
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North CarolinaChapel HillNorth CarolinaUSA
| | - Andrea M. Kaminski
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkNorth CarolinaUSA
| | - Yongmei Xu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North CarolinaChapel HillNorth CarolinaUSA
| | | | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkNorth CarolinaUSA
| | | | - Jian Liu
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North CarolinaChapel HillNorth CarolinaUSA
| | - Lars C. Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of HealthResearch Triangle ParkNorth CarolinaUSA
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18
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Li Y, Umbach DM, Krahn JM, Shats I, Li X, Li L. Predicting tumor response to drugs based on gene-expression biomarkers of sensitivity learned from cancer cell lines. BMC Genomics 2021; 22:272. [PMID: 33858332 PMCID: PMC8048084 DOI: 10.1186/s12864-021-07581-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 04/04/2021] [Indexed: 02/07/2023] Open
Abstract
Background Human cancer cell line profiling and drug sensitivity studies provide valuable information about the therapeutic potential of drugs and their possible mechanisms of action. The goal of those studies is to translate the findings from in vitro studies of cancer cell lines into in vivo therapeutic relevance and, eventually, patients’ care. Tremendous progress has been made. Results In this work, we built predictive models for 453 drugs using data on gene expression and drug sensitivity (IC50) from cancer cell lines. We identified many known drug-gene interactions and uncovered several potentially novel drug-gene associations. Importantly, we further applied these predictive models to ~ 17,000 bulk RNA-seq samples from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database to predict drug sensitivity for both normal and tumor tissues. We created a web site for users to visualize and download our predicted data (https://manticore.niehs.nih.gov/cancerRxTissue). Using trametinib as an example, we showed that our approach can faithfully recapitulate the known tumor specificity of the drug. Conclusions We demonstrated that our approach can predict drugs that 1) are tumor-type specific; 2) elicit higher sensitivity from tumor compared to corresponding normal tissue; 3) elicit differential sensitivity across breast cancer subtypes. If validated, our prediction could have relevance for preclinical drug testing and in phase I clinical design. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07581-7.
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Affiliation(s)
- Yuanyuan Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr., Research Triangle Park, MD A3-03, Durham, NC, 27709, USA
| | - David M Umbach
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr., Research Triangle Park, MD A3-03, Durham, NC, 27709, USA
| | - Juno M Krahn
- Genome Integrity & Structural Biology Laboratory, Research Triangle Park, Durham, NC, 27709, USA
| | - Igor Shats
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA
| | - Xiaoling Li
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Dr., Research Triangle Park, MD A3-03, Durham, NC, 27709, USA.
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19
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Pillon MC, Frazier MN, Dillard LB, Williams JG, Kocaman S, Krahn JM, Perera L, Hayne CK, Gordon J, Stewart ZD, Sobhany M, Deterding LJ, Hsu AL, Dandey VP, Borgnia MJ, Stanley RE. Cryo-EM structures of the SARS-CoV-2 endoribonuclease Nsp15 reveal insight into nuclease specificity and dynamics. Nat Commun 2021; 12:636. [PMID: 33504779 PMCID: PMC7840905 DOI: 10.1038/s41467-020-20608-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
Nsp15, a uridine specific endoribonuclease conserved across coronaviruses, processes viral RNA to evade detection by host defense systems. Crystal structures of Nsp15 from different coronaviruses have shown a common hexameric assembly, yet how the enzyme recognizes and processes RNA remains poorly understood. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15, in both apo and UTP-bound states. The cryo-EM reconstructions, combined with biochemistry, mass spectrometry, and molecular dynamics, expose molecular details of how critical active site residues recognize uridine and facilitate catalysis of the phosphodiester bond. Mass spectrometry revealed the accumulation of cyclic phosphate cleavage products, while analysis of the apo and UTP-bound datasets revealed conformational dynamics not observed by crystal structures that are likely important to facilitate substrate recognition and regulate nuclease activity. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, 1 Baylor Plaza, Houston, Texas, 77030, USA.
| | - Meredith N Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Lucas B Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Seda Kocaman
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Cassandra K Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
- Cambridge Institute for Medical Research, Cambridge, UK
- Department of Haematology, University of Cambridge, Cambridge, UK
- Wellcome Trust-Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Zachary D Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Leesa J Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Venkata P Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC, 27709, USA.
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20
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Schellenberg MJ, Appel CD, Riccio AA, Butler LR, Krahn JM, Liebermann JA, Cortés-Ledesma F, Williams RS. Ubiquitin stimulated reversal of topoisomerase 2 DNA-protein crosslinks by TDP2. Nucleic Acids Res 2020; 48:6310-6325. [PMID: 32356875 DOI: 10.1093/nar/gkaa318] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 03/30/2020] [Accepted: 04/20/2020] [Indexed: 11/12/2022] Open
Abstract
Tyrosyl-DNA phosphodiesterase 2 (TDP2) reverses Topoisomerase 2 DNA-protein crosslinks (TOP2-DPCs) in a direct-reversal pathway licensed by ZATTZNF451 SUMO2 E3 ligase and SUMOylation of TOP2. TDP2 also binds ubiquitin (Ub), but how Ub regulates TDP2 functions is unknown. Here, we show that TDP2 co-purifies with K63 and K27 poly-Ubiquitinated cellular proteins independently of, and separately from SUMOylated TOP2 complexes. Poly-ubiquitin chains of ≥ Ub3 stimulate TDP2 catalytic activity in nuclear extracts and enhance TDP2 binding of DNA-protein crosslinks in vitro. X-ray crystal structures and small-angle X-ray scattering analysis of TDP2-Ub complexes reveal that the TDP2 UBA domain binds K63-Ub3 in a 1:1 stoichiometric complex that relieves a UBA-regulated autoinhibitory state of TDP2. Our data indicates that that poly-Ub regulates TDP2-catalyzed TOP2-DPC removal, and TDP2 single nucleotide polymorphisms can disrupt the TDP2-Ubiquitin interface.
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Affiliation(s)
- Matthew J Schellenberg
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - C Denise Appel
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Amanda A Riccio
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Logan R Butler
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jenna A Liebermann
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla Universidad Pablo de Olavide-Junta de Andalucía, 41092 Sevilla, Spain
| | - Felipe Cortés-Ledesma
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), CSIC-Universidad de Sevilla Universidad Pablo de Olavide-Junta de Andalucía, 41092 Sevilla, Spain.,Topology and DNA breaks Group, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - R Scott Williams
- Structural Cell Biology Group, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, US Department of Health and Human Services, Research Triangle Park, NC 27709, USA
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21
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Pillon MC, Frazier MN, Dillard LB, Williams JG, Kocaman S, Krahn JM, Perera L, Hayne CK, Gordon J, Stewart ZD, Sobhany M, Deterding LJ, Hsu AL, Dandey VP, Borgnia MJ, Stanley RE. Cryo-EM Structures of the SARS-CoV-2 Endoribonuclease Nsp15. bioRxiv 2020:2020.08.11.244863. [PMID: 32803198 PMCID: PMC7427136 DOI: 10.1101/2020.08.11.244863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
New therapeutics are urgently needed to inhibit SARS-CoV-2, the virus responsible for the on-going Covid-19 pandemic. Nsp15, a uridine-specific endoribonuclease found in all coronaviruses, processes viral RNA to evade detection by RNA-activated host defense systems, making it a promising drug target. Previous work with SARS-CoV-1 established that Nsp15 is active as a hexamer, yet how Nsp15 recognizes and processes viral RNA remains unknown. Here we report a series of cryo-EM reconstructions of SARS-CoV-2 Nsp15. The UTP-bound cryo-EM reconstruction at 3.36 Å resolution provides molecular details into how critical residues within the Nsp15 active site recognize uridine and facilitate catalysis of the phosphodiester bond, whereas the apo-states reveal active site conformational heterogeneity. We further demonstrate the specificity and mechanism of nuclease activity by analyzing Nsp15 products using mass spectrometry. Collectively, these findings advance understanding of how Nsp15 processes viral RNA and provide a structural framework for the development of new therapeutics.
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Affiliation(s)
- Monica C. Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Meredith N. Frazier
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lucas B. Dillard
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G. Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Seda Kocaman
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M. Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Lalith Perera
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Cassandra K. Hayne
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jacob Gordon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Zachary D. Stewart
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J. Deterding
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Allen L. Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Venkata P. Dandey
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E. Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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22
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Duff MR, Gabel SA, Pedersen LC, DeRose EF, Krahn JM, Howell EE, London RE. The Structural Basis for Nonsteroidal Anti-Inflammatory Drug Inhibition of Human Dihydrofolate Reductase. J Med Chem 2020; 63:8314-8324. [PMID: 32658475 DOI: 10.1021/acs.jmedchem.0c00546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although nonsteroidal anti-inflammatory drugs (NSAIDs) target primarily cyclooxygenase enzymes, a subset of NSAIDs containing carboxylate groups also has been reported to competitively inhibit dihydrofolate reductase (DHFR). In this study, we have characterized NSAID interactions with human DHFR based on kinetic, NMR, and X-ray crystallographic methods. The NSAIDs target a region of the folate binding site that interacts with the p-aminobenzoyl-l-glutamate (pABG) moiety of folate and inhibit cooperatively with ligands that target the adjacent pteridine-recognition subsite. NSAIDs containing benzoate or salicylate groups were identified as having the highest potency. Among those tested, diflunisal, a salicylate derivative not previously identified to have anti-folate activity, was found to have a Ki of 34 μM, well below peak plasma diflunisal levels reached at typical dosage levels. The potential of these drugs to interfere with the inflammatory process by multiple pathways introduces the possibility of further optimization to design dual-targeted analogs.
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Affiliation(s)
- Michael R Duff
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Scott A Gabel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Eugene F DeRose
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Elizabeth E Howell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
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23
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Pillon MC, Hsu AL, Krahn JM, Williams JG, Goslen KH, Sobhany M, Borgnia MJ, Stanley RE. Cryo-EM reveals active site coordination within a multienzyme pre-rRNA processing complex. Nat Struct Mol Biol 2019; 26:830-839. [PMID: 31488907 PMCID: PMC6733591 DOI: 10.1038/s41594-019-0289-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
Abstract
Ribosome assembly is a complex process reliant on the coordination of trans-acting enzymes to produce functional ribosomal subunits and secure the translational capacity of cells. The endoribonuclease (RNase) Las1 and the polynucleotide kinase (PNK) Grc3 assemble into a multienzyme complex, herein designated RNase PNK, to orchestrate processing of precursor ribosomal RNA (rRNA). RNase PNK belongs to the functionally diverse HEPN nuclease superfamily, whose members rely on distinct cues for nuclease activation. To establish how RNase PNK coordinates its dual enzymatic activities, we solved a series of cryo-EM structures of Chaetomium thermophilum RNase PNK in multiple conformational states. The structures reveal that RNase PNK adopts a butterfly-like architecture, harboring a composite HEPN nuclease active site flanked by discrete RNA kinase sites. We identify two molecular switches that coordinate nuclease and kinase function. Together, our structures and corresponding functional studies establish a new mechanism of HEPN nuclease activation essential for ribosome production.
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Affiliation(s)
- Monica C Pillon
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Allen L Hsu
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Jason G Williams
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Kevin H Goslen
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mack Sobhany
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Robin E Stanley
- Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA.
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24
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Li Y, Li M, Shats I, Krahn JM, Flake GP, Umbach DM, Li X, Li L. Glypican 6 is a putative biomarker for metastatic progression of cutaneous melanoma. PLoS One 2019; 14:e0218067. [PMID: 31199813 PMCID: PMC6568403 DOI: 10.1371/journal.pone.0218067] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 05/26/2019] [Indexed: 01/01/2023] Open
Abstract
Due to the poor prognosis of advanced metastatic melanoma, it is crucial to find early biomarkers that help identify which melanomas will metastasize. By comparing the gene expression data from primary and cutaneous melanoma samples from The Cancer Genome Atlas (TCGA), we identified GPC6 among a set of genes whose expression levels can distinguish between primary melanoma and regional cutaneous/subcutaneous metastases. Glypicans are thought to play a role in tumor growth by regulating the signaling pathways of Wnt, Hedgehogs, fibroblast growth factors (FGFs), and bone morphogenetic proteins (BMPs). We showed that GPC6 expression was up-regulated in a melanoma cell line compared to normal melanocytes and in metastatic melanoma compared to primary melanoma. Furthermore, GPC6 expression was positively correlated with genes largely involved in cell adhesion and migration in both melanoma samples and in RNA-seq samples from other TCGA tumors. Our results suggest that GPC6 may play a role in tumor metastatic progression. In TCGA melanoma samples, we also showed that GPC6 expression was negatively correlated with miR-509-3p, which has previously been shown to function as a tumor suppressor in various cancer cell lines. We overexpressed miR-509-3p in A375 melanoma cells and showed that GPC6 expression was significantly suppressed. This result suggested that GPC6 was a putative target of miR-509-3p in melanoma. Together, our findings identified GPC6 as an early biomarker for melanoma metastatic progression, one that can be regulated by miR-509-3p.
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Affiliation(s)
- Yuanyuan Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Melissa Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Igor Shats
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Juno M. Krahn
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Gordon P. Flake
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - David M. Umbach
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Xiaoling Li
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, Durham, North Carolina, United States of America
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25
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Abstract
Metformin is the most commonly prescribed treatment for type II diabetes and related disorders; however, molecular insights into its mode(s) of action have been limited by an absence of structural data. Structural considerations along with a growing body of literature demonstrating its effects on one-carbon metabolism suggest the possibility of folate mimicry and anti-folate activity. Motivated by the growing recognition that anti-diabetic biguanides may act directly upon the gut microbiome, we have determined structures of the complexes formed between the anti-diabetic biguanides (phenformin, buformin, and metformin) and Escherichia coli dihydrofolate reductase (ecDHFR) based on nuclear magnetic resonance, crystallographic, and molecular modeling studies. Interligand Overhauser effects indicate that metformin can form ternary complexes with p-aminobenzoyl-l-glutamate (pABG) as well as other ligands that occupy the region of the folate-binding site that interacts with pABG; however, DHFR inhibition is not cooperative. The biguanides competitively inhibit the activity of ecDHFR, with the phenformin inhibition constant being 100-fold lower than that of metformin. This inhibition may be significant at concentrations present in the gut of treated individuals, and inhibition of DHFR in intestinal mucosal cells may also occur if accumulation levels are sufficient. Perturbation of folate homeostasis can alter the pyridine nucleotide redox ratios that are important regulators of cellular metabolism.
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Affiliation(s)
- Scott A Gabel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health , 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Michael R Duff
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health , 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Eugene F DeRose
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health , 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health , 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
| | - Elizabeth E Howell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health , 111 T. W. Alexander Drive, Research Triangle Park, North Carolina 27709, United States
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26
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Li Y, Kang K, Krahn JM, Croutwater N, Lee K, Umbach DM, Li L. A comprehensive genomic pan-cancer classification using The Cancer Genome Atlas gene expression data. BMC Genomics 2017; 18:508. [PMID: 28673244 PMCID: PMC5496318 DOI: 10.1186/s12864-017-3906-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 06/27/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The Cancer Genome Atlas (TCGA) has generated comprehensive molecular profiles. We aim to identify a set of genes whose expression patterns can distinguish diverse tumor types. Those features may serve as biomarkers for tumor diagnosis and drug development. METHODS Using RNA-seq expression data, we undertook a pan-cancer classification of 9,096 TCGA tumor samples representing 31 tumor types. We randomly assigned 75% of samples into training and 25% into testing, proportionally allocating samples from each tumor type. RESULTS We could correctly classify more than 90% of the test set samples. Accuracies were high for all but three of the 31 tumor types, in particular, for READ (rectum adenocarcinoma) which was largely indistinguishable from COAD (colon adenocarcinoma). We also carried out pan-cancer classification, separately for males and females, on 23 sex non-specific tumor types (those unrelated to reproductive organs). Results from these gender-specific analyses largely recapitulated results when gender was ignored. Remarkably, more than 80% of the 100 most discriminative genes selected from each gender separately overlapped. Genes that were differentially expressed between genders included BNC1, FAT2, FOXA1, and HOXA11. FOXA1 has been shown to play a role for sexual dimorphism in liver cancer. The differentially discriminative genes we identified might be important for the gender differences in tumor incidence and survival. CONCLUSIONS We were able to identify many sets of 20 genes that could correctly classify more than 90% of the samples from 31 different tumor types using TCGA RNA-seq data. This accuracy is remarkable given the number of the tumor types and the total number of samples involved. We achieved similar results when we analyzed 23 non-sex-specific tumor types separately for males and females. We regard the frequency with which a gene appeared in those sets as measuring its importance for tumor classification. One third of the 50 most frequently appearing genes were pseudogenes; the degree of enrichment may be indicative of their importance in tumor classification. Lastly, we identified a few genes that might play a role in sexual dimorphism in certain cancers.
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Affiliation(s)
- Yuanyuan Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - Kai Kang
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - Juno M Krahn
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - Nicole Croutwater
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - Kevin Lee
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - David M Umbach
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Durham, NC, 27709, USA.
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27
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Abstract
Heparan sulfate (HS) is a sulfated polysaccharide exhibiting essential physiological functions. HS 6-O-sulfotransferase (6-OST) transfers a sulfo group to the 6-OH position of glucosamine units to confer a variety of HS biological activities. There are three different isoforms of 6-OST in the human genome. Here, we report crystal structures of the ternary complex of 6-OST with the sulfo donor analog 3'-phosphoadenosine 5'-phosphate and three different oligosaccharide substrates at 1.95 to 2.1 Å resolutions. Structural and mutational analyses reveal amino acid residues that contribute to catalysis and substrate recognition of 6-OST. Unexpectedly, the structures reveal 6-OST engages HS in a completely different orientation than other HS sulfotransferases and sheds light on the basic HS requirements for specificity. These findings also contribute structural information to understand mutations in human 6-OST isoform 1 associated with the human genetic disease idiopathic hypogonadotropic hypogonadism characterized by incomplete or lack of puberty.
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Affiliation(s)
- Yongmei Xu
- Division
of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Andrea F. Moon
- Genome
Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, United States
| | - Shuqin Xu
- Division
of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
- School
of Pharmaceutical Science, Jiangnan University, Wuxi 214122, China
| | - Juno M. Krahn
- Genome
Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, United States
| | - Jian Liu
- Division
of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Lars C. Pedersen
- Genome
Integrity and Structural Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, United States
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28
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Moon AF, Krahn JM, Lu X, Cuneo MJ, Pedersen LC. Structural characterization of the virulence factor Sda1 nuclease from Streptococcus pyogenes. Nucleic Acids Res 2016; 44:3946-57. [PMID: 26969731 PMCID: PMC4856990 DOI: 10.1093/nar/gkw143] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/25/2016] [Indexed: 11/22/2022] Open
Abstract
Infection by Group A Streptococcus pyogenes (GAS) is a leading cause of severe invasive disease in humans, including streptococcal toxic shock syndrome and necrotizing fasciitis. GAS infections lead to nearly 163,000 annual deaths worldwide. Hypervirulent strains of S. pyogenes have evolved a plethora of virulence factors that aid in disease—by promoting bacterial adhesion to host cells, subsequent invasion of deeper tissues and blocking the immune system's attempts to eradicate the infection. Expression and secretion of the extracellular nuclease Sda1 is advantageous for promoting bacterial dissemination throughout the host organism, and evasion of the host's innate immune response. Here we present two crystal structures of Sda1, as well as biochemical studies to address key structural features and surface residues involved in DNA binding and catalysis. In the active site, Asn211 is observed to directly chelate a hydrated divalent metal ion and Arg124, on the putative substrate binding loop, likely stabilizes the transition state during phosphodiester bond cleavage. These structures provide a foundation for rational drug design of small molecule inhibitors to be used in prevention of invasive streptococcal disease.
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Affiliation(s)
- Andrea F Moon
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Xun Lu
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Matthew J Cuneo
- Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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29
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Li Y, Krahn JM, Flake GP, Umbach DM, Li L. Toward predicting metastatic progression of melanoma based on gene expression data. Pigment Cell Melanoma Res 2015; 28:453-63. [PMID: 25847062 PMCID: PMC4469521 DOI: 10.1111/pcmr.12374] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 03/27/2015] [Indexed: 01/20/2023]
Abstract
Primary and metastatic melanoma tumors share the same cell origin, making it challenging to identify genomic biomarkers that can differentiate them. Primary tumors themselves can be heterogeneous, reflecting ongoing genomic changes as they progress toward metastasizing. We developed a computational method to explore this heterogeneity and to predict metastatic progression of the primary tumors. We applied our method separately to gene expression and to microRNA (miRNA) expression data from ~450 primary and metastatic skin cutaneous melanoma (SKCM) samples from the Cancer Genome Atlas (TCGA). Metastatic progression scores from RNA-seq data were significantly associated with clinical staging of patients' lymph nodes, whereas scores from miRNA-seq data were significantly associated with Clark's level. The loss of expression of many characteristic epithelial lineage genes in primary SKCM tumor samples was highly correlated with predicted progression scores. We suggest that those genes/miRNAs might serve as putative biomarkers for SKCM metastatic progression.
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Affiliation(s)
- Yuanyuan Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - Juno M. Krahn
- Genome Integrity & Structural Biology Laboratory, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - Gordon P. Flake
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - David M. Umbach
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
| | - Leping Li
- Biostatistics and Computational Biology Branch, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
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30
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Singh D, Gawel D, Itsko M, Hochkoeppler A, Krahn JM, London RE, Schaaper RM. Structure of Escherichia coli dGTP triphosphohydrolase: a hexameric enzyme with DNA effector molecules. J Biol Chem 2015; 290:10418-29. [PMID: 25694425 DOI: 10.1074/jbc.m115.636936] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Indexed: 01/23/2023] Open
Abstract
The Escherichia coli dgt gene encodes a dGTP triphosphohydrolase whose detailed role still remains to be determined. Deletion of dgt creates a mutator phenotype, indicating that the dGTPase has a fidelity role, possibly by affecting the cellular dNTP pool. In the present study, we have investigated the structure of the Dgt protein at 3.1-Å resolution. One of the obtained structures revealed a protein hexamer that contained two molecules of single-stranded DNA. The presence of DNA caused significant conformational changes in the enzyme, including in the catalytic site of the enzyme. Dgt preparations lacking DNA were able to bind single-stranded DNA with high affinity (Kd ∼ 50 nM). DNA binding positively affected the activity of the enzyme: dGTPase activity displayed sigmoidal (cooperative) behavior without DNA but hyperbolic (Michaelis-Menten) kinetics in its presence, consistent with a specific lowering of the apparent Km for dGTP. A mutant Dgt enzyme was also created containing residue changes in the DNA binding cleft. This mutant enzyme, whereas still active, was incapable of DNA binding and could no longer be stimulated by addition of DNA. We also created an E. coli strain containing the mutant dgt gene on the chromosome replacing the wild-type gene. The mutant also displayed a mutator phenotype. Our results provide insight into the allosteric regulation of the enzyme and support a physiologically important role of DNA binding.
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Affiliation(s)
- Deepa Singh
- From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Damian Gawel
- the Department of Biochemistry and Molecular Biology, Center of Postgraduate Medical Education, 01-813 Warsaw, Poland, and
| | - Mark Itsko
- From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | | | - Juno M Krahn
- From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Robert E London
- From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Roel M Schaaper
- From the Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709,
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31
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Gabel SA, Smith CE, Cuneo MJ, Mueller GA, Kirby TW, DeRose EF, Krahn JM, London RE. Characterization of the redox transition of the XRCC1 N-terminal domain. Structure 2014; 22:1754-1763. [PMID: 25456813 DOI: 10.1016/j.str.2014.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/11/2014] [Accepted: 09/05/2014] [Indexed: 10/24/2022]
Abstract
XRCC1, a scaffold protein involved in DNA repair, contains an N-terminal domain (X1NTD) that interacts specifically with DNA polymerase β. It was recently discovered that X1NTD contains a disulfide switch that allows it to adopt either of two metamorphic structures. In the present study, we demonstrate that formation of an N-terminal proline carbimate adduct resulting from the nonenzymatic reaction of Pro2 with CO2 is essential for stabilizing the oxidized structure, X1NTDox. The kinetic response of X1NTDred to H2O2, monitored by NMR, was determined to be very slow, consistent with involvement of the buried, kinetically trapped Cys12 residue, but was significantly accelerated by addition of protein disulfide isomerase or by Cu(2+). NMR analysis of a sample containing the pol β polymerase domain, and both the reduced and oxidized forms of X1NTD, indicates that the oxidized form binds to the enzyme 25-fold more tightly than the reduced form.
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Affiliation(s)
- Scott A Gabel
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Cassandra E Smith
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Matthew J Cuneo
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Geoffrey A Mueller
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Thomas W Kirby
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Eugene F DeRose
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Robert E London
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
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32
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Liu C, Sheng J, Krahn JM, Perera L, Xu Y, Hsieh PH, Dou W, Liu J, Pedersen LC. Molecular mechanism of substrate specificity for heparan sulfate 2-O-sulfotransferase. J Biol Chem 2014; 289:13407-18. [PMID: 24652287 DOI: 10.1074/jbc.m113.530535] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heparan sulfate (HS) is an abundant polysaccharide in the animal kingdom with essential physiological functions. HS is composed of sulfated saccharides that are biosynthesized through a complex pathway involving multiple enzymes. In vivo regulation of this process remains unclear. HS 2-O-sulfotransferase (2OST) is a key enzyme in this pathway. Here, we report the crystal structure of the ternary complex of 2OST, 3'-phosphoadenosine 5'-phosphate, and a heptasaccharide substrate. Utilizing site-directed mutagenesis and specific oligosaccharide substrate sequences, we probed the molecular basis of specificity and 2OST position in the ordered HS biosynthesis pathway. These studies revealed that Arg-80, Lys-350, and Arg-190 of 2OST interact with the N-sulfo groups near the modification site, consistent with the dependence of 2OST on N-sulfation. In contrast, 6-O-sulfo groups on HS are likely excluded by steric and electrostatic repulsion within the active site supporting the hypothesis that 2-O-sulfation occurs prior to 6-O-sulfation. Our results provide the structural evidence for understanding the sequence of enzymatic events in this pathway.
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Affiliation(s)
- Chunhui Liu
- From the Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599
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33
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Zheng X, Pedersen LC, Gabel SA, Mueller GA, Cuneo MJ, DeRose EF, Krahn JM, London RE. Selective unfolding of one Ribonuclease H domain of HIV reverse transcriptase is linked to homodimer formation. Nucleic Acids Res 2014; 42:5361-77. [PMID: 24574528 PMCID: PMC4005681 DOI: 10.1093/nar/gku143] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
HIV-1 reverse transcriptase (RT), a critical enzyme of the HIV life cycle and an important drug target, undergoes complex and largely uncharacterized conformational rearrangements that underlie its asymmetric folding, dimerization and subunit-selective ribonuclease H domain (RH) proteolysis. In the present article we have used a combination of NMR spectroscopy, small angle X-ray scattering and X-ray crystallography to characterize the p51 and p66 monomers and the conformational maturation of the p66/p66′ homodimer. The p66 monomer exists as a loosely structured molecule in which the fingers/palm/connection, thumb and RH substructures are connected by flexible (disordered) linking segments. The initially observed homodimer is asymmetric and includes two fully folded RH domains, while exhibiting other conformational features similar to that of the RT heterodimer. The RH′ domain of the p66′ subunit undergoes selective unfolding with time constant ∼6.5 h, consistent with destabilization due to residue transfer to the polymerase′ domain on the p66′ subunit. A simultaneous increase in the intensity of resonances near the random coil positions is characterized by a similar time constant. Consistent with the residue transfer hypothesis, a construct of the isolated RH domain lacking the two N-terminal residues is shown to exhibit reduced stability. These results demonstrate that RH′ unfolding is coupled to homodimer formation.
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Affiliation(s)
- Xunhai Zheng
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
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34
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Xu D, Young JH, Krahn JM, Song D, Corbett KD, Chazin WJ, Pedersen LC, Esko JD. Stable RAGE-heparan sulfate complexes are essential for signal transduction. ACS Chem Biol 2013; 8:1611-20. [PMID: 23679870 DOI: 10.1021/cb4001553] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RAGE (Receptor for Advanced Glycation End-Products) has emerged as a major receptor that mediates vascular inflammation. Signaling through RAGE by damage-associated molecular pattern molecules often leads to uncontrolled inflammation that exacerbates the impact of the underlying disease. Oligomerization of RAGE is believed to play an essential role in signal transduction, but the molecular mechanism of oligomerization remains elusive. Here we report that RAGE activation of Erk1/2 phosphorylation on endothelial cells in response to a number of ligands depends on a mechanism that involves heparan sulfate-induced hexamerization of the RAGE extracellular domain. Structural studies of the extracellular V-C1 domain-dodecasaccharide complex by X-ray diffraction and small-angle X-ray scattering revealed that the hexamer consists of a trimer of dimers, with a stoichiometry of 2:1 RAGE:dodecasaccharide. Mutagenesis studies mapped the heparan sulfate binding site and the interfacial surface between the monomers and demonstrated that electrostatic interactions with heparan sulfate and intermonomer hydrophobic interactions work in concert to stabilize the dimer. The importance of oligomerization was demonstrated by inhibition of signaling with a new epitope-defined monoclonal antibody that specifically targets oligomerization. These findings indicate that RAGE-heparan sulfate oligomeric complexes are essential for signaling and that interfering with RAGE oligomerization might be of therapeutic value.
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Affiliation(s)
- Ding Xu
- Department of Cellular and Molecular
Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
92093, United States
| | - Jeffrey H. Young
- Department of Cellular and Molecular
Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
92093, United States
| | - Juno M. Krahn
- Laboratory
of Structural Biology,
National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park,
North Carolina 27709, United States
| | - Danyin Song
- Department of Cellular and Molecular
Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
92093, United States
| | - Kevin D. Corbett
- Ludwig Institute for Cancer Research
and Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093,
United States
| | - Walter J. Chazin
- Departments
of Biochemistry
and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Lars C. Pedersen
- Laboratory
of Structural Biology,
National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park,
North Carolina 27709, United States
| | - Jeffrey D. Esko
- Department of Cellular and Molecular
Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, California
92093, United States
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35
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Baucom J, Transue T, Fuentes-Cabrera M, Krahn JM, Darden TA, Sagui C. Molecular dynamics simulations of the d(CCAACGTTGG)(2) decamer in crystal environment: comparison of atomic point-charge, extra-point, and polarizable force fields. J Chem Phys 2006; 121:6998-7008. [PMID: 15473761 DOI: 10.1063/1.1788631] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Molecular dynamics simulations of the DNA duplex d(CCAACGTTGG)(2) were used to study the relationship between DNA sequence and structure in a crystal environment. Three different force fields were used: a traditional description based on atomic point charges, a polarizable force field, and an "extra-point" force field (with additional charges on extranuclear sites). It is found that all the force fields reproduce fairly well the sequence-dependent features of the experimental structure. The polarizable force field, however, provides the most accurate representation of the crystal structure and the sequence-dependent effects observed in the experiment. These results point out to the need of the inclusion of polarization for accurate descriptions of DNA.
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Affiliation(s)
- Jason Baucom
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
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36
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Chen S, Burgner JW, Krahn JM, Smith JL, Zalkin H. Tryptophan fluorescence monitors multiple conformational changes required for glutamine phosphoribosylpyrophosphate amidotransferase interdomain signaling and catalysis. Biochemistry 1999; 38:11659-69. [PMID: 10512621 DOI: 10.1021/bi991060o] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Single tryptophan residues were incorporated into each of three peptide segments that play key roles in the structural transition of ligand-free, inactive glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase to the active enzyme-substrate complex. Intrinsic tryptophan fluorescence and fluorescence quenching were used to monitor changes in a phosphoribosyltransferase (PRTase) "flexible loop", a "glutamine loop", and a C-terminal helix. Steady state fluorescence changes resulting from substrate binding were used to calculate binding constants and to detect the structural rearrangements that coordinate reactions at active sites for glutamine hydrolysis and PRTase catalysis. Pre-steady state kinetics of enzyme.PRPP and enzyme.PRPP.glutamine complex formation were determined from stopped-flow fluorescence measurements. The kinetics of the formation of the enzyme.PRPP complex were consistent with a model with two or more steps in which rapid equilibrium binding of PRPP is followed by a slow enzyme isomerization. This isomerization is ascribed to the closing of the PRTase flexible loop and is likely the rate-limiting step in the reaction of PRPP with NH(3). The pre-steady state kinetics for binding glutamine to the binary enzyme. PRPP complex could also be fit to a model involving rapid equilibrium binding of glutamine followed by an enzyme isomerization step. The changes monitored by fluorescence account for the interconversions between "end state" structures determined previously by X-ray crystallography and define an intermediate enzyme.PRPP conformer.
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Affiliation(s)
- S Chen
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907, USA
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37
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Abstract
Crystal structures of glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase from Escherichia coli have been determined to 2.0-A resolution in the absence of ligands, and to 2.5-A resolution with the feedback inhibitor AMP bound to the PRPP catalytic site. Glutamine PRPP amidotransferase (GPATase) employs separate catalytic domains to abstract nitrogen from the amide of glutamine and to transfer nitrogen to the acceptor substrate PRPP. The unliganded and AMP-bound structures, which are essentially identical, are interpreted as the inhibited form of the enzyme because the two active sites are disconnected and the PRPP active site is solvent exposed. The structures were compared with a previously reported 3.0-A structure of the homologous Bacillus subtilis enzyme (Smith JL et al., 1994, Science 264:1427-1433). The comparison indicates a pattern of conservation of peptide structures involved with catalysis and variability in enzyme regulatory functions. Control of glutaminase activity, communication between the active sites, and regulation by feedback inhibitors are addressed differently by E. coli and B. subtilis GPATases. The E. coli enzyme is a prototype for the metal-free GPATases, whereas the B. subtilis enzyme represents the metal-containing enzymes. The structure of the E. coli enzyme suggests that a common ancestor of the two enzyme subfamilies may have included an Fe-S cluster.
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Affiliation(s)
- C R Muchmore
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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38
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Krahn JM, Kim JH, Burns MR, Parry RJ, Zalkin H, Smith JL. Coupled formation of an amidotransferase interdomain ammonia channel and a phosphoribosyltransferase active site. Biochemistry 1997; 36:11061-8. [PMID: 9333323 DOI: 10.1021/bi9714114] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Activation of gluatmine phosphoribosylpyrophosphate (RPPP) amidotransferase (GPATase) by binding of a PRPP substrate analog results in the formation of a 20 A channel connecting the active site for glutamine hydrolysis in one domain with the PRPP site in a second domain. This solvent-inaccessible channel permits transfer of the NH3 intermediate between the two active sites. Tunneling of NH3 may be a common mechanism for glutamine amidotransferase-catalyzed nitrogen transfer and for coordination of catalysis at two distinct active sites in complex enzymes. The 2.4 A crystal structure of the active conformer of GPATase also provides the first description of an intact active site for the phosphoribosyltransferase (PRTase) family of nucleotide synthesis and salvage enzymes. Chemical assistance to catalysis is provided primarily by the substrate and secondarily by the enzyme in the proposed structure-based mechanism. Different catalytic and inhibitory modes of divalent cation binding to the PRTase active site are revealed in the active conformer of the enzyme and in a feedback-inhibited GMP complex.
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Affiliation(s)
- J M Krahn
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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39
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Kim JH, Krahn JM, Tomchick DR, Smith JL, Zalkin H. Structure and function of the glutamine phosphoribosylpyrophosphate amidotransferase glutamine site and communication with the phosphoribosylpyrophosphate site. J Biol Chem 1996; 271:15549-57. [PMID: 8663035 DOI: 10.1074/jbc.271.26.15549] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Glutamine phosphoribosylpyrophosphate (PRPP) amidotransferase from Escherichia coli exhibits a basal PRPP-independent glutaminase activity having a kcat/Km that is 0.3% of fully active enzyme. Binding of PRPP activates the enzyme by a structural change that lowers the Km for glutamine 100-fold and couples glutamine hydrolysis to synthesis of 5-phosphoribosylamine. By analysis of the x-ray structure of the glutamine site containing bound 6-diazo-5-oxonorleucine, a glutamine affinity analog, and by site-directed mutagenesis we have identified residues important for glutamine binding, catalysis, and coupling with PRPP. Tyr74 is a key residue in the coupling between the sites for glutamine in the NH2-terminal domain and PRPP in the COOH-terminal domain. Arg73 and Asp127 have roles in glutamine binding. The x-ray structure indicates that there are no amino acid side chains sufficiently close to Cys1 to participate as a proton acceptor in formation of the thiolate needed for nucleophilic attack on the carboxamide of glutamine, nor as a general acid for amide nitrogen transfer. Based on the x-ray model of the glutamine site and analysis of a mutant enzyme we propose that the free NH2 terminus of Cys1 functions as the proton acceptor and donor. The results indicate that the side chain of Asn101 and the backbone nitrogen of Gly102 function to stabilize a tetrahedral oxyanion resulting from attack of Cys1 on the glutamine carboxamide. Cys1, Arg73, Asn101, Gly102, and Asp127 are conserved in the NH2-terminal domain of a subfamily of amidotransferases that includes asparagine synthetase, glucosamine 6-phosphate synthase, and glutamate synthase, implying a common function in the four enzymes. Tyr74, on the other hand, is conserved only in glutamine PRPP amidotransferase sequences consistent with a specific role in interdomain coupling. The catalytic framework of key glutamine site residues supports the assignment of glutamine PRPP amidotransferase to a recently described Ntn (NH2-terminal nucleophile) hydrolase family of enzymes.
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Affiliation(s)
- J H Kim
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907-1153, USA
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