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Mendoza J, Purchal M, Yamada K, Koutmos M. Structure of full-length cobalamin-dependent methionine synthase and cofactor loading captured in crystallo. Nat Commun 2023; 14:6365. [PMID: 37821448 PMCID: PMC10567725 DOI: 10.1038/s41467-023-42037-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 09/28/2023] [Indexed: 10/13/2023] Open
Abstract
Cobalamin-dependent methionine synthase (MS) is a key enzyme in methionine and folate one-carbon metabolism. MS is a large multi-domain protein capable of binding and activating three substrates: homocysteine, folate, and S-adenosylmethionine for methylation. Achieving three chemically distinct methylations necessitates significant domain rearrangements to facilitate substrate access to the cobalamin cofactor at the right time. The distinct conformations required for each reaction have eluded structural characterization as its inherently dynamic nature renders structural studies difficult. Here, we use a thermophilic MS homolog (tMS) as a functional MS model. Its exceptional stability enabled characterization of MS in the absence of cobalamin, marking the only studies of a cobalamin-binding protein in its apoenzyme state. More importantly, we report the high-resolution full-length MS structure, ending a multi-decade quest. We also capture cobalamin loading in crystallo, providing structural insights into holoenzyme formation. Our work paves the way for unraveling how MS orchestrates large-scale domain rearrangements crucial for achieving challenging chemistries.
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Affiliation(s)
- Johnny Mendoza
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Meredith Purchal
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- New England Biolabs, Inc., Ipswich, MA, 01938, England
| | - Kazuhiro Yamada
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Markos Koutmos
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
- Program in Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA.
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2
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A Combined Spectroscopy and Computational Molecular Docking Investigation on the Coupling Between β-lactoglobulin Dimers and Vanillin. FOOD BIOPHYS 2022. [DOI: 10.1007/s11483-022-09772-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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3
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Sun SQ, Chen SL. An Unprecedented Ring-Contraction Mechanism in Cobalamin-Dependent Radical S-Adenosylmethionine Enzymes. J Phys Chem Lett 2020; 11:6812-6818. [PMID: 32787210 DOI: 10.1021/acs.jpclett.0c01725] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A unique member of the family of cobalamin (Cbl)-dependent radical S-adenosylmethionine (SAM) enzymes, OxsB, catalyzes the ring constriction of deoxyadenosine triphosphate (dATP) to the base oxetane aldehyde phosphate, a crucial precursor for oxetanocin A (OXT-A), which is an antitumor, antiviral, and antibacterial compound. This enzyme reveals a new catalytic function for this big family that is different from the common methylation. On the basis of density functional theory calculations, a mechanism has been proposed to mainly include that the generation of 5'-deoxyadenosine radical, a hydrogen transfer forming 2'-dATP radical, and a Cbl-catalyzed ring contraction of the deoxyribose in 2'-dATP radical. The ring contraction is a concerted rearrangement step accompanied by an electron transfer from the deoxyribose hydroxyl oxygen to CoIII without any ring-opening intermediate. CoIICbl has been ruled out as an active state. Other mechanistic characteristics are also revealed. This unprecedented non-methylation mechanism provides a new catalytic repertoire for the family of radical SAM enzymes, representing a new class of ring-contraction enzymes.
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Affiliation(s)
- Shuo-Qi Sun
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China
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4
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Structural basis for stereoselective dehydration and hydrogen-bonding catalysis by the SAM-dependent pericyclase LepI. Nat Chem 2019; 11:812-820. [PMID: 31332284 PMCID: PMC6708486 DOI: 10.1038/s41557-019-0294-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/14/2019] [Indexed: 12/04/2022]
Abstract
LepI is an S-adenosylmethionine (SAM)-dependent pericyclase that catalyzes the formation of 2-pyridone natural product leporin C. Biochemical characterization showed LepI can catalyze the stereoselective dehydration to yield a reactive (E)-quinone methide that can undergo bifurcating intramolecular Diels-Alder (IMDA) and hetero-Diels-Alder (HDA) cyclizations from an ambimodal transition state, as well as a [3,3]-retro-Claisen rearrangement to recycle the IMDA product into leporin C. Here we solved the X-ray crystal structures of SAM-bound LepI and in complex with a substrate analog, the product leporin C, and a retro-Claisen reaction transition-state analog to understand the structural basis for the multitude of reactions. Structural and mutational analysis revealed how Nature evolves a classic methyltransferase active site into one that can serve as a dehydratase and a multifunctional pericyclase. Catalysis of both sets of reactions employs H133 and R295, two active site residues that are not found in canonical methyltransferases. An alternative role of SAM, which is not found to be in direct contact with the substrate, is also proposed.
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5
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Yang Z, Liu F, Steeves AH, Kulik HJ. Quantum Mechanical Description of Electrostatics Provides a Unified Picture of Catalytic Action Across Methyltransferases. J Phys Chem Lett 2019; 10:3779-3787. [PMID: 31244268 DOI: 10.1021/acs.jpclett.9b01555] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Methyl transferases (MTases) are a well-studied class of enzymes for which competing enzymatic enhancement mechanisms have been suggested, ranging from structural methyl group CH···X hydrogen bonds (HBs) to electrostatic- and charge-transfer-driven stabilization of the transition state (TS). We identified all Class I MTases for which reasonable resolution (<2.0 Å) crystal structures could be used to form catalytically competent ternary complexes for multiscale (i.e., quantum-mechanical/molecular-mechanical or QM/MM) simulation of the SN2 methyl transfer reaction coordinate. The four Class I MTases studied have both distinct functions (e.g., protein repair or biosynthesis) and substrate nucleophiles (i.e., C, N, or O). While CH···X HBs stabilize all reactant complexes, no universal TS stabilization role is found for these interactions in MTases. A consistent picture is instead obtained through analysis of charge transfer and electrostatics, wherein much of cofactor-substrate charge separation is maintained in the TS region, and electrostatic potential is correlated with substrate nucleophilicity (i.e., intrinsic reactivity).
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Affiliation(s)
- Zhongyue Yang
- Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Fang Liu
- Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Adam H Steeves
- Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Heather J Kulik
- Department of Chemical Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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6
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Fick RJ, Horowitz S, McDole BG, Clay MC, Mehl RA, Al-Hashimi HM, Scheiner S, Trievel RC. Structural and Functional Characterization of Sulfonium Carbon-Oxygen Hydrogen Bonding in the Deoxyamino Sugar Methyltransferase TylM1. Biochemistry 2019; 58:2152-2159. [PMID: 30810306 DOI: 10.1021/acs.biochem.8b01141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The N-methyltransferase TylM1 from Streptomyces fradiae catalyzes the final step in the biosynthesis of the deoxyamino sugar mycaminose, a substituent of the antibiotic tylosin. The high-resolution crystal structure of TylM1 bound to the methyl donor S-adenosylmethionine (AdoMet) illustrates a network of carbon-oxygen (CH···O) hydrogen bonds between the substrate's sulfonium cation and residues within the active site. These interactions include hydrogen bonds between the methyl and methylene groups of the AdoMet sulfonium cation and the hydroxyl groups of Tyr14 and Ser120 in the enzyme. To examine the functions of these interactions, we generated Tyr14 to phenylalanine (Y14F) and Ser120 to alanine (S120A) mutations to selectively ablate the CH···O hydrogen bonding to AdoMet. The TylM1 S120A mutant exhibited a modest decrease in its catalytic efficiency relative to that of the wild type (WT) enzyme, whereas the Y14F mutation resulted in an approximately 30-fold decrease in catalytic efficiency. In contrast, site-specific substitution of Tyr14 by the noncanonical amino acid p-aminophenylalanine partially restored activity comparable to that of the WT enzyme. Correlatively, quantum mechanical calculations of the activation barrier energies of WT TylM1 and the Tyr14 mutants suggest that substitutions that abrogate hydrogen bonding with the AdoMet methyl group impair methyl transfer. Together, these results offer insights into roles of CH···O hydrogen bonding in modulating the catalytic efficiency of TylM1.
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Affiliation(s)
- Robert J Fick
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Scott Horowitz
- Department of Chemistry and Biochemistry, Knoebel Institute for Healthy Aging , University of Denver , Denver , Colorado 80208 , United States
| | - Brandon G McDole
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Mary C Clay
- Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics , Oregon State University , Corvallis , Oregon 97331 , United States
| | - Hashim M Al-Hashimi
- Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States
| | - Steve Scheiner
- Department of Chemistry and Biochemistry , Utah State University , Logan , Utah 84322 , United States
| | - Raymond C Trievel
- Department of Biological Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
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Michalczyk M, Zierkiewicz W, Wysokiński R, Scheiner S. Hexacoordinated Tetrel‐Bonded Complexes between TF4(T=Si, Ge, Sn, Pb) and NCH: Competition between σ‐ and π‐Holes. Chemphyschem 2019; 20:959-966. [DOI: 10.1002/cphc.201900072] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 02/15/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Mariusz Michalczyk
- Faculty of ChemistryWrocław University of Science and Technology Wybrzeże, Wyspiańskiego 27 50-370 Wrocław Poland
| | - Wiktor Zierkiewicz
- Faculty of ChemistryWrocław University of Science and Technology Wybrzeże, Wyspiańskiego 27 50-370 Wrocław Poland
| | - Rafał Wysokiński
- Faculty of ChemistryWrocław University of Science and Technology Wybrzeże, Wyspiańskiego 27 50-370 Wrocław Poland
| | - Steve Scheiner
- Department of Chemistry and BiochemistryUtah State University Logan, Utah 84322-0300 United States
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Mattioli EJ, Bottoni A, Calvaresi M. DNAzymes at Work: A DFT Computational Investigation on the Mechanism of 9DB1. J Chem Inf Model 2019; 59:1547-1553. [DOI: 10.1021/acs.jcim.8b00815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Edoardo Jun Mattioli
- Dipartimento di Chimica “G. Ciamician”, Alma Mater Studiorum - Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
| | - Andrea Bottoni
- Dipartimento di Chimica “G. Ciamician”, Alma Mater Studiorum - Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
| | - Matteo Calvaresi
- Dipartimento di Chimica “G. Ciamician”, Alma Mater Studiorum - Università di Bologna, V. F. Selmi 2, 40126 Bologna, Italy
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9
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Dependence of NMR chemical shifts upon CH bond lengths of a methyl group involved in a tetrel bond. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2018.10.069] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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10
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Crystallographic and Computational Characterization of Methyl Tetrel Bonding in S-Adenosylmethionine-Dependent Methyltransferases. Molecules 2018; 23:molecules23112965. [PMID: 30428636 PMCID: PMC6278250 DOI: 10.3390/molecules23112965] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 10/19/2018] [Accepted: 10/20/2018] [Indexed: 11/17/2022] Open
Abstract
Tetrel bonds represent a category of non-bonding interaction wherein an electronegative atom donates a lone pair of electrons into the sigma antibonding orbital of an atom in the carbon group of the periodic table. Prior computational studies have implicated tetrel bonding in the stabilization of a preliminary state that precedes the transition state in SN2 reactions, including methyl transfer. Notably, the angles between the tetrel bond donor and acceptor atoms coincide with the prerequisite geometry for the SN2 reaction. Prompted by these findings, we surveyed crystal structures of methyltransferases in the Protein Data Bank and discovered multiple instances of carbon tetrel bonding between the methyl group of the substrate S-adenosylmethionine (AdoMet) and electronegative atoms of small molecule inhibitors, ions, and solvent molecules. The majority of these interactions involve oxygen atoms as the Lewis base, with the exception of one structure in which a chlorine atom of an inhibitor functions as the electron donor. Quantum mechanical analyses of a representative subset of the methyltransferase structures from the survey revealed that the calculated interaction energies and spectral properties are consistent with the values for bona fide carbon tetrel bonds. The discovery of methyl tetrel bonding offers new insights into the mechanism underlying the SN2 reaction catalyzed by AdoMet-dependent methyltransferases. These findings highlight the potential of exploiting these interactions in developing new methyltransferase inhibitors.
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11
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Scheiner S. Ability of IR and NMR Spectral Data to Distinguish between a Tetrel Bond and a Hydrogen Bond. J Phys Chem A 2018; 122:7852-7862. [DOI: 10.1021/acs.jpca.8b07631] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, United States
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