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Guo S, Jiang M, Wang W, Chen X, Wei Q, Wang M. Crystal structure of methyltransferase CbiL from Akkermansia muciniphila. Biochem Biophys Res Commun 2024; 722:150165. [PMID: 38805786 DOI: 10.1016/j.bbrc.2024.150165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024]
Abstract
Akkermansia muciniphila is a mucin-degrading probiotic that colonizes the gastrointestinal tract. Genomic analysis identified a set of genes involved in the biosynthesis of corrin ring, including the cobalt factor II methyltransferase CbiL, in some phylogroups of A. muciniphila, implying a potential capacity for de novo synthesis of cobalamin. In this work, we determined the crystal structure of CbiL from A. muciniphila at 2.3 Å resolution. AmCbiL exists as a dimer both in solution and in crystal, and each protomer consists of two α/β domains, the N-terminal domain and the C-terminal domain, consistent with the folding of typical class III MTases. The two domains create an open trough, potentially available to bind the substrates SAM and cobalt factor II. Sequence and structural comparisons with other CbiLs, assisted by computer modeling, suggest that AmCbiL should have cobalt factor II C-20 methyltransferase activity. Our results support that certain strains of A. muciniphila may be capable of synthesizing cobalamin de novo.
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Affiliation(s)
- Shuoxuan Guo
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China
| | - Meiyu Jiang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China
| | - Wenfeng Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China
| | - Xi Chen
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China
| | - Qinghao Wei
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China
| | - Mingzhu Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, Anhui, China; School of Life Sciences, Anhui University, Hefei 230601, Anhui, China; Key Laboratory of Human Microenvironment and Precision Medicine of Anhui Higher Education Institutes, Anhui University, Hefei 230601, Anhui, China.
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Mathur Y, Hazra AB. Methylations in vitamin B 12 biosynthesis and catalysis. Curr Opin Struct Biol 2022; 77:102490. [PMID: 36371846 DOI: 10.1016/j.sbi.2022.102490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/12/2022]
Abstract
Vitamin B12 is an essential biomolecule that assists in the catalysis of methyl transfer and radical-based reactions in cellular metabolism. The structure of B12 is characterized by a tetrapyrrolic corrin ring with a central cobalt ion coordinated with an upper ligand, and a lower ligand anchored via a nucleotide loop. Multiple methyl groups decorate B12, and their presence (or absence) have structural and functional consequences. In this minireview, we focus on the methyl groups that distinguish vitamin B12 from other tetrapyrrolic biomolecules and from its own naturally occurring analogues called cobamides. We draw information from recent advances in the field to understand the origins of these methyl groups and the enzymes that incorporate them, and discuss their biological significance.
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Affiliation(s)
- Yamini Mathur
- Department of Biology, Indian Institute of Science Education and Research, Pune, India. https://twitter.com/yaminipmathur
| | - Amrita B Hazra
- Department of Biology, Indian Institute of Science Education and Research, Pune, India; Department of Chemistry, Indian Institute of Science Education and Research, Pune, India.
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Abstract
This review summarizes research performed over the last 23 years on the genetics, enzyme structures and functions, and regulation of the expression of the genes encoding functions involved in adenosylcobalamin (AdoCbl, or coenzyme B12) biosynthesis. It also discusses the role of coenzyme B12 in the physiology of Salmonella enterica serovar Typhimurium LT2 and Escherichia coli. John Roth's seminal contributions to the field of coenzyme B12 biosynthesis research brought the power of classical and molecular genetic, biochemical, and structural approaches to bear on the extremely challenging problem of dissecting the steps of what has turned out to be one of the most complex biosynthetic pathways known. In E. coli and serovar Typhimurium, uro'gen III represents the first branch point in the pathway, where the routes for cobalamin and siroheme synthesis diverge from that for heme synthesis. The cobalamin biosynthetic pathway in P. denitrificans was the first to be elucidated, but it was soon realized that there are at least two routes for cobalamin biosynthesis, representing aerobic and anaerobic variations. The expression of the AdoCbl biosynthetic operon is complex and is modulated at different levels. At the transcriptional level, a sensor response regulator protein activates the transcription of the operon in response to 1,2-Pdl in the environment. Serovar Typhimurium and E. coli use ethanolamine as a source of carbon, nitrogen, and energy. In addition, and unlike E. coli, serovar Typhimurium can also grow on 1,2-Pdl as the sole source of carbon and energy.
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Liscombe DK, Louie GV, Noel JP. Architectures, mechanisms and molecular evolution of natural product methyltransferases. Nat Prod Rep 2012; 29:1238-50. [PMID: 22850796 DOI: 10.1039/c2np20029e] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The addition of a methyl moiety to a small chemical is a common transformation in the biosynthesis of natural products across all three domains of life. These methylation reactions are most often catalysed by S-adenosyl-L-methionine (SAM)-dependent methyltransferases (MTs). MTs are categorized based on the electron-rich, methyl accepting atom, usually O, N, C, or S. SAM-dependent natural product MTs (NPMTs) are responsible for the modification of a wide array of structurally distinct substrates, including signalling and host defense compounds, pigments, prosthetic groups, cofactors, cell membrane and cell wall components, and xenobiotics. Most notably, methylation modulates the bioavailability, bioactivity, and reactivity of acceptor molecules, and thus exerts a central role on the functional output of many metabolic pathways. Our current understanding of the structural enzymology of NPMTs groups these phylogenetically diverse enzymes into two MT-superfamily fold classes (class I and class III). Structural biology has also shed light on the catalytic mechanisms and molecular bases for substrate specificity for over fifty NPMTs. These biophysical-based approaches have contributed to our understanding of NPMT evolution, demonstrating how a widespread protein fold evolved to accommodate chemically diverse methyl acceptors and to catalyse disparate mechanisms suited to the physiochemical properties of the target substrates. This evolutionary diversity suggests that NPMTs may serve as starting points for generating new biocatalysts.
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Affiliation(s)
- David K Liscombe
- Howard Hughes Medical Institute, Jack H. Skirball Center for Chemical Biology and Proteomics, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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Seyedarabi A, Hutchison T, To TT, Deery E, Brindley A, Warren MJ, Pickersgill RW. Cloning, purification and preliminary crystallographic analysis of cobalamin methyltransferases from Rhodobacter capsulatus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1652-6. [PMID: 21139217 DOI: 10.1107/s1744309110042910] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 10/21/2010] [Indexed: 11/10/2022]
Abstract
Of the 30 biosynthetic steps necessary for the production of cobalamin (vitamin B12), eight involve the addition of S-adenosylmethionine-derived methyl groups to the tetrapyrrole framework. These eight methyl additions are catalysed by six canonical methyltransferase domains and one noncanonical methyltransferase domain. Recombinant forms of four methyltransferases from Rhodobacter capsulatus, CobJ, CobM, CobF and CobL, and of the C-terminal noncanonical domain of CobL (CobL-C) have been crystallized, some in more than one crystal form. Most of the crystals diffracted to beyond 2.5 Å resolution and all are suitable for structure determination. Crystals of CobM and CobJ, which are involved in ring contraction, and of CobL, which is involved in two methylations and decarboxylation, are reported for the first time.
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Affiliation(s)
- Arefeh Seyedarabi
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England
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Frank S, Deery E, Brindley AA, Leech HK, Lawrence A, Heathcote P, Schubert HL, Brocklehurst K, Rigby SEJ, Warren MJ, Pickersgill RW. Elucidation of substrate specificity in the cobalamin (vitamin B12) biosynthetic methyltransferases. Structure and function of the C20 methyltransferase (CbiL) from Methanothermobacter thermautotrophicus. J Biol Chem 2007; 282:23957-69. [PMID: 17567575 DOI: 10.1074/jbc.m703827200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ring contraction during cobalamin (vitamin B12) biosynthesis requires a seemingly futile methylation of the C20 position of the tetrapyrrole framework. Along the anaerobic route, this reaction is catalyzed by CbiL, which transfers a methyl group from S-adenosyl-L-methionine to cobalt factor II to generate cobalt factor III. CbiL belongs to the class III methyltransferases and displays similarity to other cobalamin biosynthetic methyltransferases that are responsible for the regiospecific methylation of a number of positions on the tetrapyrrole molecular canvas. In an attempt to understand how CbiL selectively methylates the C20 position, a detailed structure function analysis of the enzyme has been undertaken. In this paper, we demonstrate that the enzyme methylates the C20 position, that its preferred substrate is cobalt factor II, and that the metal ion does not undergo any oxidation change during the course of the reaction. The enzyme was crystallized, and its structure was determined by x-ray crystallography, revealing that the 26-kDa protein has a similar overall topology to other class III enzymes. This helped in the identification of some key amino acid residues (Asp(104), Lys(176), and Tyr(220)). Analysis of mutant variants of these groups has allowed us to suggest potential roles that these side chains may play in substrate binding and catalysis. EPR analysis of binary and ternary complexes indicate that the protein donates a fifth ligand to the cobalt ion via a gated mechanism to prevent transfer of the methyl group to water. The chemical logic underpinning the methylation is discussed.
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Affiliation(s)
- Stefanie Frank
- Protein Science Group, Department of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, United Kingdom
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Holliday GL, Thornton JM, Marquet A, Smith AG, Rébeillé F, Mendel R, Schubert HL, Lawrence AD, Warren MJ. Evolution of enzymes and pathways for the biosynthesis of cofactors. Nat Prod Rep 2007; 24:972-87. [PMID: 17898893 DOI: 10.1039/b703107f] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The evolution of metabolic pathways is discussed with reference to the biosynthesis of a number of vitamins and cofactors. Retrograde and patchwork models are highlighted and their relevance to our knowledge of pathway processes and enzymes is examined. Pathway complexity is explained in terms of the acquisition of broad specificity enzymes.
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Affiliation(s)
- Gemma L Holliday
- European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, UK CB10 1SD.
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