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Xiong J, Xu D. Decarboxylation Mechanism of iso-Orotate Decarboxylase Revisited. J Chem Theory Comput 2024; 20:4218-4228. [PMID: 38720241 DOI: 10.1021/acs.jctc.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
iso-Orotate decarboxylase (IDCase), which is involved in the thymidine salvage pathway, has attracted considerable interest owing to its chemical similarity to a hypothetical DNA decarboxylase in mammals. Although valuable insights into the active DNA demethylation of 5-methyl-cytosine can be obtained from the decarboxylation mechanism of 5-carboxyl-uracil (5caU) catalyzed by IDCase, this mechanism remains under debate. In this study, the catalytic mechanism of 5caU decarboxylation by IDCase was studied using hybrid quantum mechanics/molecular mechanics (QM/MM) methodologies and density functional theory (DFT) calculations with a truncated model. The calculations supported a mechanism involving three sequential stages: activation of the 5caU substrate via proton transfer from an arginine (R262') to the carboxyl group of 5caU, formation of a tetrahedral intermediate, and decarboxylation of the tetrahedral intermediate to generate uracil as the product. The reaction pathways and structures obtained using the QM/MM and DFT methods coincided with each other. These simulations provided detailed insights into the unique mechanism of IDCase, clarifying various unresolved issues, such as the critical role of R262'. In addition, aspartate D323 was found to act as a general base in the tetrahedral intermediate formation step and a general acid in the later C-C bond cleavage step.
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Affiliation(s)
- Jing Xiong
- School of Pharmacy, Chengdu Medical College, Chengdu, Sichuan 610500, P. R. China
| | - Dingguo Xu
- MOE Key Laboratory of Green Chemistry & Technology, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, P. R. China
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2
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Calvelo M, Males A, Alteen MG, Willems LI, Vocadlo DJ, Davies GJ, Rovira C. Human O-GlcNAcase Uses a Preactivated Boat-skew Substrate Conformation for Catalysis. Evidence from X-ray Crystallography and QM/MM Metadynamics. ACS Catal 2023; 13:13672-13678. [PMID: 37969138 PMCID: PMC10636738 DOI: 10.1021/acscatal.3c02378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 09/07/2023] [Indexed: 11/17/2023]
Abstract
Human O-linked β-N-acetylglucosaminidase (hOGA) is one of the two enzymes involved in nuclear and cytoplasmic protein O-GlcNAcylation, an essential post-translational modification. The enzyme catalyzes the hydrolysis of the GlcNAc-O-(Ser/Thr) glycosidic bonds via anchimeric assistance through the 2-acetamido group of the GlcNAc sugar. However, the conformational itinerary of the GlcNAc ring during catalysis remains unclear. Here we report the crystal structure of wild type hOGA in complex with a nonhydrolyzable glycopeptide substrate and elucidate the full enzyme catalytic mechanism using QM/MM metadynamics. We show that the enzyme can bind the substrate in either a chair- or a boat-like conformation, but only the latter is catalytically competent, leading to the reaction products via 1,4B/1S3 → [4E]‡ → 4C1 and 4C1 → [4E]‡ → 1,4B/1S3 conformational itineraries for the first and second catalytic reaction steps, respectively. Our results reconcile previous experimental observations for human and bacterial OGA and will aid the development of more effective OGA inhibitors for diseases associated with impaired O-GlcNAcylation.
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Affiliation(s)
- Martín Calvelo
- Departament
de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Alexandra Males
- York
Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York YO10 5DD, United Kingdom
| | - Matthew G. Alteen
- Department
of Chemistry & Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Lianne I. Willems
- York
Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York YO10 5DD, United Kingdom
| | - David J. Vocadlo
- Department
of Chemistry & Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Gideon J. Davies
- York
Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York YO10 5DD, United Kingdom
| | - Carme Rovira
- Departament
de Química Inorgànica i Orgànica & IQTCUB, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, 23, 08020 Barcelona, Spain
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Zhao J, Lang M. New insight into protein glycosylation in the development of Alzheimer's disease. Cell Death Discov 2023; 9:314. [PMID: 37626031 PMCID: PMC10457297 DOI: 10.1038/s41420-023-01617-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/09/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Alzheimer's disease (AD) is a chronic neurodegenerative disease that seriously endangers the physical and mental health of patients, however, there are still no effective drugs or methods to cure this disease up to now. Protein glycosylation is the most common modifications of the translated proteins in eukaryotic cells. Recently many researches disclosed that aberrant glycosylation happens in some important AD-related proteins, such as APP, Tau, Reelin and CRMP-2, etc, suggesting a close link between abnormal protein glycosylation and AD. Because of its complexity and diversity, glycosylation is thus considered a completely new entry point for understanding the precise cause of AD. This review comprehensively summarized the currently discovered changes in protein glycosylation patterns in AD, and especially introduced the latest progress on the mechanism of protein glycosylation affecting the progression of AD and the potential application of protein glycosylation in AD detection and treatment, thereby providing a wide range of opportunities for uncovering the pathogenesis of AD and promoting the translation of glycosylation research into future clinical applications.
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Affiliation(s)
- Jingwei Zhao
- CAS Center for Excellence in Biotic Interactions, College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Minglin Lang
- CAS Center for Excellence in Biotic Interactions, College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China.
- College of Life Science, Agricultural University of Hebei, Baoding, 071000, China.
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González-Cuesta M, Sidhu P, Ashmus RA, Males A, Proceviat C, Madden Z, Rogalski JC, Busmann JA, Foster LJ, García Fernández JM, Davies GJ, Ortiz Mellet C, Vocadlo DJ. Bicyclic Picomolar OGA Inhibitors Enable Chemoproteomic Mapping of Its Endogenous Post-translational Modifications. J Am Chem Soc 2022; 144:832-844. [PMID: 34985906 DOI: 10.1021/jacs.1c10504] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Owing to its roles in human health and disease, the modification of nuclear, cytoplasmic, and mitochondrial proteins with O-linked N-acetylglucosamine residues (O-GlcNAc) has emerged as a topic of great interest. Despite the presence of O-GlcNAc on hundreds of proteins within cells, only two enzymes regulate this modification. One of these enzymes is O-GlcNAcase (OGA), a dimeric glycoside hydrolase that has a deep active site cleft in which diverse substrates are accommodated. Chemical tools to control OGA are emerging as essential resources for helping to decode the biochemical and cellular functions of the O-GlcNAc pathway. Here we describe rationally designed bicyclic thiazolidine inhibitors that exhibit superb selectivity and picomolar inhibition of human OGA. Structures of these inhibitors in complex with human OGA reveal the basis for their exceptional potency and show that they extend out of the enzyme active site cleft. Leveraging this structure, we create a high affinity chemoproteomic probe that enables simple one-step purification of endogenous OGA from brain and targeted proteomic mapping of its post-translational modifications. These data uncover a range of new modifications, including some that are less-known, such as O-ubiquitination and N-formylation. We expect that these inhibitors and chemoproteomics probes will prove useful as fundamental tools to decipher the mechanisms by which OGA is regulated and directed to its diverse cellular substrates. Moreover, the inhibitors and structures described here lay out a blueprint that will enable the creation of chemical probes and tools to interrogate OGA and other carbohydrate active enzymes.
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Affiliation(s)
- Manuel González-Cuesta
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, 41012 Sevilla, Spain
| | - Peter Sidhu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Roger A Ashmus
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Alexandra Males
- Department of Chemistry. University of York, York YO10 5DD, United Kingdom
| | - Cameron Proceviat
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Zarina Madden
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jason C Rogalski
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jil A Busmann
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - José M García Fernández
- Instituto de Investigaciones Químicas (IIQ), CSIC, Universidad de Sevilla, 41092 Sevilla, Spain
| | - Gideon J Davies
- Department of Chemistry. University of York, York YO10 5DD, United Kingdom
| | - Carmen Ortiz Mellet
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, 41012 Sevilla, Spain
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.,Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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