1
|
Sweeney P, Galliford A, Kumar A, Raju D, Krishna NB, Sutherland E, Leo CJ, Fisher G, Lalitha R, Muthuraj L, Sigamani G, Oehler V, Synowsky S, Shirran SL, Gloster TM, Czekster CM, Kumar P, da Silva RG. Structure, dynamics, and molecular inhibition of the Staphylococcus aureus m 1A22-tRNA methyltransferase TrmK. J Biol Chem 2022; 298:102040. [PMID: 35595101 PMCID: PMC9190014 DOI: 10.1016/j.jbc.2022.102040] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 11/29/2022] Open
Abstract
The enzyme m1A22-tRNA methyltransferase (TrmK) catalyzes the transfer of a methyl group to the N1 of adenine 22 in bacterial tRNAs. TrmK is essential for Staphylococcus aureus survival during infection but has no homolog in mammals, making it a promising target for antibiotic development. Here, we characterize the structure and function of S. aureus TrmK (SaTrmK) using X-ray crystallography, binding assays, and molecular dynamics simulations. We report crystal structures for the SaTrmK apoenzyme as well as in complexes with methyl donor SAM and co-product product SAH. Isothermal titration calorimetry showed that SAM binds to the enzyme with favorable but modest enthalpic and entropic contributions, whereas SAH binding leads to an entropic penalty compensated for by a large favorable enthalpic contribution. Molecular dynamics simulations point to specific motions of the C-terminal domain being altered by SAM binding, which might have implications for tRNA recruitment. In addition, activity assays for SaTrmK-catalyzed methylation of A22 mutants of tRNALeu demonstrate that the adenine at position 22 is absolutely essential. In silico screening of compounds suggested the multifunctional organic toxin plumbagin as a potential inhibitor of TrmK, which was confirmed by activity measurements. Furthermore, LC-MS data indicated the protein was covalently modified by one equivalent of the inhibitor, and proteolytic digestion coupled with LC-MS identified Cys92 in the vicinity of the SAM-binding site as the sole residue modified. These results identify a cryptic binding pocket of SaTrmK, laying a foundation for future structure-based drug discovery.
Collapse
Affiliation(s)
- Pamela Sweeney
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Ashleigh Galliford
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | | | - Dinesh Raju
- Kcat Enzymatic Private Limited, Bangalore, India
| | | | - Emmajay Sutherland
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Caitlin J Leo
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Gemma Fisher
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | | | | | | | - Verena Oehler
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Silvia Synowsky
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Sally L Shirran
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Tracey M Gloster
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Clarissa M Czekster
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK
| | - Pravin Kumar
- Kcat Enzymatic Private Limited, Bangalore, India.
| | - Rafael G da Silva
- School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, UK.
| |
Collapse
|
2
|
Nejatie A, Steves E, Gauthier N, Baker J, Nesbitt J, McMahon SA, Oehler V, Thornton NJ, Noyovitz B, Khazaei K, Byers BW, Zandberg WF, Gloster TM, Moore MM, Bennet AJ. Kinetic and Structural Characterization of Sialidases (Kdnases) from Ascomycete Fungal Pathogens. ACS Chem Biol 2021; 16:2632-2640. [PMID: 34724608 DOI: 10.1021/acschembio.1c00666] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sialidases catalyze the release of sialic acid from the terminus of glycan chains. We previously characterized the sialidase from the opportunistic fungal pathogen, Aspergillus fumigatus, and showed that it is a Kdnase. That is, this enzyme prefers 3-deoxy-d-glycero-d-galacto-non-2-ulosonates (Kdn glycosides) as the substrate compared to N-acetylneuraminides (Neu5Ac). Here, we report characterization and crystal structures of putative sialidases from two other ascomycete fungal pathogens, Aspergillus terreus (AtS) and Trichophyton rubrum (TrS). Unlike A. fumigatus Kdnase (AfS), hydrolysis with the Neu5Ac substrates was negligible for TrS and AtS; thus, TrS and AtS are selective Kdnases. The second-order rate constant for hydrolysis of aryl Kdn glycosides by AtS is similar to that by AfS but 30-fold higher by TrS. The structures of these glycoside hydrolase family 33 (GH33) enzymes in complex with a range of ligands for both AtS and TrS show subtle changes in ring conformation that mimic the Michaelis complex, transition state, and covalent intermediate formed during catalysis. In addition, they can aid identification of important residues for distinguishing between Kdn and Neu5Ac substrates. When A. fumigatus, A. terreus, and T. rubrum were grown in chemically defined media, Kdn was detected in mycelial extracts, but Neu5Ac was only observed in A. terreus or T. rubrum extracts. The C8 monosaccharide 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) was also identified in A. fumigatus and T. rubrum samples. A fluorescent Kdn probe was synthesized and revealed the localization of AfS in vesicles at the cell surface.
Collapse
Affiliation(s)
- Ali Nejatie
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Elizabeth Steves
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Nick Gauthier
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Jamie Baker
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Jason Nesbitt
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Stephen A. McMahon
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, Fife, U.K
| | - Verena Oehler
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, Fife, U.K
| | - Nicholas J. Thornton
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, Fife, U.K
| | - Benjamin Noyovitz
- Department of Chemistry, I. K. Barber Faculty of Science, University of British Columbia, 3247 University Way, Kelowna V1V 1V7, British Columbia, Canada
| | - Kobra Khazaei
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Brock W. Byers
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Wesley F. Zandberg
- Department of Chemistry, I. K. Barber Faculty of Science, University of British Columbia, 3247 University Way, Kelowna V1V 1V7, British Columbia, Canada
| | - Tracey M. Gloster
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews KY16 9ST, Fife, U.K
| | - Margo M. Moore
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| | - Andrew J. Bennet
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby V5A 1S6, British
Columbia, Canada
| |
Collapse
|
3
|
Machado TFG, Purg M, McMahon SA, Read BJ, Oehler V, Åqvist J, Gloster TM, da Silva RG. Dissecting the Mechanism of ( R)-3-Hydroxybutyrate Dehydrogenase by Kinetic Isotope Effects, Protein Crystallography, and Computational Chemistry. ACS Catal 2020; 10:15019-15032. [PMID: 33391858 PMCID: PMC7773212 DOI: 10.1021/acscatal.0c04736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 10/30/2020] [Revised: 11/24/2020] [Indexed: 12/21/2022]
Abstract
The enzyme (R)-3-hydroxybutyrate dehydrogenase (HBDH) catalyzes the enantioselective reduction of 3-oxocarboxylates to (R)-3-hydroxycarboxylates, the monomeric precursors of biodegradable polyesters. Despite its application in asymmetric reduction, which prompted several engineering attempts of this enzyme, the order of chemical events in the active site, their contributions to limit the reaction rate, and interactions between the enzyme and non-native 3-oxocarboxylates have not been explored. Here, a combination of kinetic isotope effects, protein crystallography, and quantum mechanics/molecular mechanics (QM/MM) calculations were employed to dissect the HBDH mechanism. Initial velocity patterns and primary deuterium kinetic isotope effects establish a steady-state ordered kinetic mechanism for acetoacetate reduction by a psychrophilic and a mesophilic HBDH, where hydride transfer is not rate limiting. Primary deuterium kinetic isotope effects on the reduction of 3-oxovalerate indicate that hydride transfer becomes more rate limiting with this non-native substrate. Solvent and multiple deuterium kinetic isotope effects suggest hydride and proton transfers occur in the same transition state. Crystal structures were solved for both enzymes complexed to NAD+:acetoacetate and NAD+:3-oxovalerate, illustrating the structural basis for the stereochemistry of the 3-hydroxycarboxylate products. QM/MM calculations using the crystal structures as a starting point predicted a higher activation energy for 3-oxovalerate reduction catalyzed by the mesophilic HBDH, in agreement with the higher reaction rate observed experimentally for the psychrophilic orthologue. Both transition states show concerted, albeit not synchronous, proton and hydride transfers to 3-oxovalerate. Setting the MM partial charges to zero results in identical reaction activation energies with both orthologues, suggesting the difference in activation energy between the reactions catalyzed by cold- and warm-adapted HBDHs arises from differential electrostatic stabilization of the transition state. Mutagenesis and phylogenetic analysis reveal the catalytic importance of His150 and Asn145 in the respective orthologues.
Collapse
Affiliation(s)
- Teresa F G Machado
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom.,School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Miha Purg
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, Uppsala SE-751 24, Sweden
| | - Stephen A McMahon
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Benjamin J Read
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Verena Oehler
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Johan Åqvist
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, Uppsala SE-751 24, Sweden
| | - Tracey M Gloster
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| | - Rafael G da Silva
- School of Chemistry and School of Biology, Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife KY16 9ST, United Kingdom
| |
Collapse
|
4
|
Artola M, Kuo CL, McMahon SA, Oehler V, Hansen T, van der Lienden M, He X, van den Elst H, Florea BI, Kermode AR, van der Marel GA, Gloster TM, Codée JDC, Overkleeft HS, Aerts JMFG. New Irreversible α-l-Iduronidase Inhibitors and Activity-Based Probes. Chemistry 2018; 24:19081-19088. [PMID: 30307091 PMCID: PMC6343074 DOI: 10.1002/chem.201804662] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [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: 09/12/2018] [Revised: 10/10/2018] [Indexed: 11/20/2022]
Abstract
Cyclophellitol aziridines are potent irreversible inhibitors of retaining glycosidases and versatile intermediates in the synthesis of activity‐based glycosidase probes (ABPs). Direct 3‐amino‐2‐(trifluoromethyl)quinazolin‐4(3H)‐one‐mediated aziridination of l‐ido‐configured cyclohexene has enabled the synthesis of new covalent inhibitors and ABPs of α‐l‐iduronidase, deficiency of which underlies the lysosomal storage disorder mucopolysaccharidosis type I (MPS I). The iduronidase ABPs react covalently and irreversibly in an activity‐based manner with human recombinant α‐l‐iduronidase (rIDUA, Aldurazyme®). The structures of IDUA when complexed with the inhibitors in a non‐covalent transition state mimicking form and a covalent enzyme‐bound form provide insights into its conformational itinerary. Inhibitors 1–3 adopt a half‐chair conformation in solution (4H3 and 3H4), as predicted by DFT calculations, which is different from the conformation of the Michaelis complex observed by crystallographic studies. Consequently, 1–3 may need to overcome an energy barrier in order to switch from the 4H3 conformation to the transition state (2, 5B) binding conformation before reacting and adopting a covalent 5S1 conformation. rIDUA can be labeled with fluorescent Cy5 ABP 2, which allows monitoring of the delivery of therapeutic recombinant enzyme to lysosomes, as is intended in enzyme replacement therapy for the treatment of MPS I patients.
Collapse
Affiliation(s)
- Marta Artola
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Chi-Lin Kuo
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Stephen A McMahon
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Verena Oehler
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Thomas Hansen
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Martijn van der Lienden
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Xu He
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Hans van den Elst
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Bogdan I Florea
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Allison R Kermode
- Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Gijsbert A van der Marel
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9ST, UK
| | - Jeroen D C Codée
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Herman S Overkleeft
- Department of Bio-organic Synthesis, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Johannes M F G Aerts
- Department of Medical Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| |
Collapse
|
5
|
Ren W, Pengelly R, Farren-Dai M, Abadi SSK, Oehler V, Akintola O, Draper J, Meanwell M, Chakladar S, Świderek K, Moliner V, Britton R, Gloster TM, Bennet AJ. Author Correction: Revealing the mechanism for covalent inhibition of glycoside hydrolases by carbasugars at an atomic level. Nat Commun 2018; 9:3700. [PMID: 30194298 PMCID: PMC6128943 DOI: 10.1038/s41467-018-06264-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Weiwu Ren
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Robert Pengelly
- Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Marco Farren-Dai
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Saeideh Shamsi Kazem Abadi
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Verena Oehler
- Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK
| | - Oluwafemi Akintola
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Jason Draper
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Michael Meanwell
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Saswati Chakladar
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Katarzyna Świderek
- Department de Química Física i Analítica, Universitat Jaume I, 12071, Castellón, Spain
| | - Vicent Moliner
- Department de Química Física i Analítica, Universitat Jaume I, 12071, Castellón, Spain
| | - Robert Britton
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9ST, UK.
| | - Andrew J Bennet
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
| |
Collapse
|
6
|
Abstract
![]()
Mammalian
β-hexosaminidases have been shown to play essential
roles in cellular physiology and health. These enzymes are responsible
for the cleavage of the monosaccharides N-acetylglucosamine
(GlcNAc) and N-acetylgalactosamine (GalNAc) from
cellular substrates. One of these β-hexosaminidases, hexosaminidase
D (HexD), encoded by the HEXDC gene, has received
little attention. No mechanistic studies have focused on the role
of this unusual nucleocytoplasmically localized β-hexosaminidase,
and its cellular function remains unknown. Using a series of kinetic
and mechanistic investigations into HexD, we define the precise catalytic
mechanism of this enzyme and establish the identities of key enzymic
residues. The preparation of synthetic aryl N-acetylgalactosaminide
substrates for HexD in combination with measurements of kinetic parameters
for wild-type and mutant enzymes, linear free energy analyses of the
enzyme-catalyzed hydrolysis of these substrates, evaluation of the
reaction by nuclear magnetic resonance, and inhibition studies collectively
reveal the detailed mechanism of action employed by HexD. HexD is
a retaining glycosidase that operates using a substrate-assisted catalytic
mechanism, has a preference for galactosaminide over glucosaminide
substrates, and shows a pH optimum in its second-order rate constant
at pH 6.5–7.0. The catalytically important residues are Asp148
and Glu149, with Glu149 serving as the general acid/base residue and
Asp148 as the polarizing residue. HexD is inhibited by Gal-NAG-thiazoline
(Ki = 420 nM). The fundamental insights
gained from this study will aid in the development of potent and selective
probes for HexD, which will serve as useful tools to improve our understanding
of the physiological role played by this unusual enzyme.
Collapse
Affiliation(s)
- Matthew G Alteen
- Department of Chemistry, Simon Fraser University , 8888 University Drive, Burnaby, BC V5A 1S6, Canada.,Biomedical Sciences Research Complex, University of St Andrews , North Haugh, St Andrews, Fife KY16 9ST, U.K
| | - Verena Oehler
- Biomedical Sciences Research Complex, University of St Andrews , North Haugh, St Andrews, Fife KY16 9ST, U.K
| | - Ivana Nemčovičová
- Department für Chemie, Universität für Bodenkultur , Muthgasse 18, A-1190 Wien, Austria
| | - Iain B H Wilson
- Department für Chemie, Universität für Bodenkultur , Muthgasse 18, A-1190 Wien, Austria
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University , 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Tracey M Gloster
- Biomedical Sciences Research Complex, University of St Andrews , North Haugh, St Andrews, Fife KY16 9ST, U.K
| |
Collapse
|
7
|
Oehler V, Filipe A, Montserret R, da Costa D, Brown G, Penin F, McLauchlan J. Structural analysis of hepatitis C virus core-E1 signal peptide and requirements for cleavage of the genotype 3a signal sequence by signal peptide peptidase. J Virol 2012; 86:7818-28. [PMID: 22593157 PMCID: PMC3421639 DOI: 10.1128/jvi.00457-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [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: 02/22/2012] [Accepted: 05/07/2012] [Indexed: 12/19/2022] Open
Abstract
The maturation of the hepatitis C virus (HCV) core protein requires proteolytic processing by two host proteases: signal peptidase (SP) and the intramembrane-cleaving protease signal peptide peptidase (SPP). Previous work on HCV genotype 1a (GT1a) and GT2a has identified crucial residues required for efficient signal peptide processing by SPP, which in turn has an effect on the production of infectious virus particles. Here we demonstrate that the JFH1 GT2a core-E1 signal peptide can be adapted to the GT3a sequence without affecting the production of infectious HCV. Through mutagenesis studies, we identified crucial residues required for core-E1 signal peptide processing, including a GT3a sequence-specific histidine (His) at position 187. In addition, the stable knockdown of intracellular SPP levels in HuH-7 cells significantly affects HCV virus titers, further demonstrating the requirement for SPP for the maturation of core and the production of infectious HCV particles. Finally, our nuclear magnetic resonance (NMR) structural analysis of a synthetic HCV JFH1 GT2a core-E1 signal peptide provides an essential structural template for a further understanding of core processing as well as the first model for an SPP substrate within its membrane environment. Our findings give deeper insights into the mechanisms of intramembrane-cleaving proteases and the impact on viral infections.
Collapse
Affiliation(s)
- Verena Oehler
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Ana Filipe
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Roland Montserret
- Bases Moléculaires et Structurales des Systèmes Infectieux, IBCP, UMR 5086, CNRS, Université de Lyon, Lyon, France
| | - Daniel da Costa
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Gaie Brown
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - François Penin
- Bases Moléculaires et Structurales des Systèmes Infectieux, IBCP, UMR 5086, CNRS, Université de Lyon, Lyon, France
| | - John McLauchlan
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| |
Collapse
|
8
|
Ho PA, Alonzo TA, Kopecky KJ, Miller KL, Kuhn J, Zeng R, Gerbing RB, Raimondi SC, Hirsch BA, Oehler V, Hurwitz CA, Franklin JL, Gamis AS, Petersdorf SH, Anderson JE, Reaman GH, Baker LH, Willman CL, Bernstein ID, Radich JP, Appelbaum FR, Stirewalt DL, Meshinchi S. Molecular alterations of the IDH1 gene in AML: a Children's Oncology Group and Southwest Oncology Group study. Leukemia 2010; 24:909-13. [PMID: 20376086 PMCID: PMC2945692 DOI: 10.1038/leu.2010.56] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [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] [Indexed: 11/10/2022]
Abstract
Recent whole-genome sequencing efforts led to the identification of IDH1R132 mutations in AML patients. We studied the prevalence and clinical implications of IDH1 genomic alterations in pediatric and adult AML. Diagnostic DNA from 531 AML patients treated on Children’s Oncology Group trial COG-AAML03P1 (N=257), and Southwest Oncology Group trials SWOG-9031, SWOG-9333, and SWOG-9500 (N=274), were tested for IDH1 mutations. Codon R132 mutations were absent in the pediatric cohort, but were found in 12/274 adult patients (4.4%, 95% CI 2.3-7.5%). IDH1R132 mutations occurred most commonly in patients with normal karyotype, and those with FLT3/ITD and NPMc mutations. Patients with IDH1R132 mutations trended towards higher median diagnostic WBC counts (59.2 × 109/L vs. 29.1 × 109/L, P=0.19) than those without mutations, but the two groups did not differ significantly in age, bone marrow blast percentage, overall survival, or relapse-free survival. Eleven patients (2.1%) harbored a novel V71I sequence alteration, which was found to be a germline polymorphism. IDH1 mutations were not detected in pediatric AML, and are uncommon in adult AML.
Collapse
Affiliation(s)
- P A Ho
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Walker M, Black EJ, Oehler V, Gillespie DA, Scott MT. Chk1 C-terminal regulatory phosphorylation mediates checkpoint activation by de-repression of Chk1 catalytic activity. Oncogene 2009; 28:2314-23. [PMID: 19421147 PMCID: PMC2857325 DOI: 10.1038/onc.2009.102] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [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: 01/19/2023]
Abstract
Chk1 is phosphorylated within its C-terminal regulatory domain by the upstream ATM/ ATR kinases during checkpoint activation, however how this modulates Chk1 function is poorly understood. Here, we show that Chk1 kinase activity is rapidly stimulated in a cell cycle phase-specific manner in response to both DNA damage and replication arrest, and that the extent and duration of activation correlates closely with regulatory phosphorylation at serines (S) S317, S345, and S366. Despite their evident co-regulation, substitutions of individual Chk1 regulatory sites with alanine (A) residues have differential effects on checkpoint proficiency and kinase activation. Thus, whereas Chk1 S345 is essential for all functions tested, mutants lacking S317 or S366 retain partial proficiency for G2/ M and S/ M checkpoint arrests triggered by DNA damage or replication arrest. These phenotypes reflect defects in Chk1 kinase induction, since the mutants are either partially (317A, 366A) or completely (345A) resistant to kinase activation. Importantly, S345 phosphorylation is impaired in Chk1 S317A and S366A mutants, suggesting that modification of adjacent SQ sites promotes this key regulatory event. Finally, we provide biochemical evidence that Chk1 catalytic activity is stimulated via a de-repression mechanism.
Collapse
Affiliation(s)
- M Walker
- Beatson Institute for Cancer Research, Garscube Estate, Glasgow, UK
| | | | | | | | | |
Collapse
|
10
|
Plaul JM, Oehler V. [Application of minicomputers for improvement of stomatological care. Part 2]. Zahntechnik (Berl) 1989; 30:223-5. [PMID: 2637572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
11
|
Plaul JM, Tumovec M, Oehler V. [Computer-supported assessment of stomatological mass examinations in children and juveniles, based on the new basic documentation in child's stomatology]. Stomatol DDR 1989; 39:415-7. [PMID: 2626773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A software packet for the evaluation of epidemiological data in Paedodontics is presented. Thereby, the works and the possibilities for the acquirement of preventive programmes are considerably facilitated.
Collapse
|
12
|
Plaul JM, Zinner R, Oehler V. [Organisation of the dispensary care of the maxillary and facial surgery using mini-computers]. Stomatol DDR 1989; 39:120-2. [PMID: 2815163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The presented hardware and software solution enables to realize an effective and complete patients' recall and thus the comprehensive dispensary care in an average special department for maxillary and facial surgery.
Collapse
|
13
|
Oehler V, Plaul J. [Application of small computers for improvement of stomatological care]. Zahntechnik (Berl) 1988; 29:263-5. [PMID: 3272508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
14
|
Krehan F, Oehler V, Gangler P. [Root canal filling--indication, technics and treatment results]. Stomatol DDR 1982; 32:452-9. [PMID: 6958107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
15
|
Oehler V. [Therapy of caries profunda]. Stomatol DDR 1981; 31:359-369. [PMID: 6949372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|