The crystal structure of tetrameric methionine adenosyltransferase from rat liver reveals the methionine-binding site 1 1Edited by R. Huber

González, Beatriz; Pajares, Marı́a A.; Hermoso, J.A.; Álvarez, Luis; Garrido, Federico; Sufrin, Janice R.; Sanz‐Aparicio, Julia

doi:10.1006/jmbi.2000.3858

Cited by 70 publications

(133 citation statements)

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“…This phenomenon, experimentally manifested as dissociation, has been described in other oligomeric proteins, such as NAD-dependent dehydrogenases and tryptophan synthase (41). This instability can be explained by the low number of interactions between dimers shown in the MAT I crystal structure (28) (Fig. 7).…”

Section: Discussionmentioning

confidence: 62%

“…The presence of these cysteines in the ␤-sheet of contact between dimers and the fact that Cys 61 is a liverspecific amino acid may be related to the special features shown by the liver-specific MAT, such as its capacity to generate two oligomeric assemblies (16). In fact, the sulfhydryls of these two cysteines appear perfectly oriented and at bonding distance in the crystal structure of MAT I (obtained in the presence of DTT) (28). As for Cys 57 and Cys 69 (another liver-specific cysteine), both are also located in the ␤-sheet B2 and close enough as to form a disulfide bond, but their sulfhydryl groups are facing opposite directions (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…This enzyme presents 10 cysteine residues/subunit (19,20), and under several in vitro and in vivo conditions it has been possible to demonstrate their role on the activity and oligomeric state: (a) inactivation and dissociation of MAT I is produced by N-ethylmaleimide (NEM) modification of two ϪSH groups (21,22); (b) site-directed mutagenesis of Cys 69 renders the enzyme mainly as dimers (23); (c) all of the mutants on the cysteines comprised between residues 35 and 105 have some effect on the MAT I/MAT III ratio (23); (d) the enzyme activity is inhibited by GSSG (2) and nitrosylation of Cys 121 (24,25); (e) inhibition of the glutathione synthesis leading to a 30% reduction in the GSH levels, and hence to the alteration of the GSH/GSSG ratio, correlates with a decrease in MAT activity (26); and (f) low MAT activity and mainly dimers are detectable under the oxidative conditions of alcohol liver cirrhosis (27). Moreover, a disulfide bond between Cys 35 and Cys 61 that are located in the ␤-sheet of contact between dimers, according to the crystal structure, has been identified (15,28). This disulfide was not detected when the protein was overexpressed in Escherichia coli, where MAT I/III appears in a concentration-dependent equilibrium (29), thus suggesting a role for it on the association.…”

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Role of an Intrasubunit Disulfide in the Association State of the Cytosolic Homo-oligomer Methionine Adenosyltransferase

Sánchez-Pérez¹,

Gasset²,

Calvete³

et al. 2003

Journal of Biological Chemistry

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Recombinant rat liver methionine adenosyltransferase has been refolded into fully active tetramers (MAT I) and dimers (MAT III), using as a source chaotrope-solubilized aggregates resulting from specific washes of inclusion bodies. The conditions of refolding, dialysis in the presence of 10 mM dithiothreitol or 10 mM GSH with 1 mM GSSG, allowed the production of both isoforms, the nature of the redox agent determining the capacity of the final product (MAT I/III) to interconvert. Refolding in the presence of 10 mM dithiothreitol yielded mainly MAT III in a concentration-dependent equilibrium with the homotetramer MAT I. However, refolding in the presence of the redox pair GSH/GSSG resulted in a stable MAT I and III mixture. Blockage of dimer-tetramer interconversion has been found related to the production of a single intramolecular disulfide in methionine adenosyltransferase during the GSH/GSSG folding process. The residues involved in this disulfide have been identified by mass spectrometry and using a set of single cysteine mutants as cysteines 35 and 61. In addition, a kinetic intermediate in the MAT I dissociation to MAT III has been detected. The physiological importance of these results is discussed in light of the structural and regulatory data available.

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Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Role of an Intrasubunit Disulfide in the Association State of the Cytosolic Homo-oligomer Methionine Adenosyltransferase

Sánchez-Pérez¹,

Gasset²,

Calvete³

et al. 2003

Journal of Biological Chemistry

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“…MjMAT displays substantially larger ellipticity at 220 nm, a wavelength characteristic of the proportion of ␣-helix. The crystal structures of the E. coli and rat liver enzymes show that they are composed of ϳ25% ␣-helix and ϳ20% ␤-sheet (26,27). The differences in CD spectra suggest that the overall secondary structure of MjMAT is more helical than the eucaryal or bacterial MAT-␣.…”

Section: Resultsmentioning

confidence: 99%

Enzymatic Properties of S-Adenosylmethionine Synthetase from the Archaeon Methanococcus jannaschii

Markham

2002

Journal of Biological Chemistry

116

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S-Adenosylmethionine synthetase (ATP:L-methionine S-adenosyltransferase, MAT) catalyzes a unique enzymatic reaction that leads to formation of the primary biological alkylating agent. MAT from the hyperthermophilic archaeon Methanococcus jannaschii (MjMAT) is a prototype of the newly discovered archaeal class of MAT proteins that are nearly unrecognizable in sequence when compared with the class that encompasses both the eucaryal and bacterial enzymes. In this study the functional properties of purified recombinant MjMAT have been evaluated. The products of the reaction are AdoMet, PP i , and P i ; >90% of the P i originates from the ␥-phosphoryl group of ATP. The circular dichroism spectrum of the dimeric MjMAT indicates that the secondary structure is more helical than the Escherichia coli counterpart (EcMAT), suggesting a different protein topology. The steady state kinetic mechanism is sequential, with random addition of ATP and methionine; AdoMet is the first product released, followed by release of PP i and P i . The substrate specificity differs remarkably from the previously characterized MATs; the nucleotide binding site has a very broad tolerance of alterations in the adenosine moiety. MjMAT has activity at 70°C comparable with that of EcMAT at 37°C, consistent with the higher temperature habitat of M. jannaschii. The activation energy for AdoMet formation is larger than that for the E. coli MAT-catalyzed reaction, in accord with the notion that enzymes from thermophilic organisms are often more rigid than their mesophilic counterparts. The broad substrate tolerance of this enzyme proffers routes to preparation of novel AdoMet analogs.

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“…Despite the plethora of MAT structures that have been published (10,11,(21)(22)(23) or deposited in the PDB, to date only one structure of human MATα2 (12) (1.2 Å resolution) and of the MAT(α2) 4 (βV2) 2 complex (4) (2.35-3.3 Å resolution) have been published. The mechanism of MAT enzyme function has been described for eMAT (11), and this has become the accepted mechanism for MAT enzymes.…”

Section: Discussionmentioning

confidence: 99%

Crystallography captures catalytic steps in human methionine adenosyltransferase enzymes

Murray

Antonyuk

Marina

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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The principal methyl donor of the cell, S-adenosylmethionine (SAMe), is produced by the highly conserved family of methionine adenosyltranferases (MATs) via an ATP-driven process. These enzymes play an important role in the preservation of life, and their dysregulation has been tightly linked to liver and colon cancers. We present crystal structures of human MATα2 containing various bound ligands, providing a "structural movie" of the catalytic steps. High-to atomic-resolution structures reveal the structural elements of the enzyme involved in utilization of the substrates methionine and adenosine and in formation of the product SAMe. MAT enzymes are also able to produce S-adenosylethionine (SAE) from substrate ethionine. Ethionine, an S-ethyl analog of the amino acid methionine, is known to induce steatosis and pancreatitis. We show that SAE occupies the active site in a manner similar to SAMe, confirming that ethionine also uses the same catalytic site to form the product SAE.methionine adenosyltransferase | cell growth | liver cancer | X-ray crystallography | methylation

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The crystal structure of tetrameric methionine adenosyltransferase from rat liver reveals the methionine-binding site 1 1Edited by R. Huber

Cited by 70 publications

References 50 publications

Role of an Intrasubunit Disulfide in the Association State of the Cytosolic Homo-oligomer Methionine Adenosyltransferase

Role of an Intrasubunit Disulfide in the Association State of the Cytosolic Homo-oligomer Methionine Adenosyltransferase

Enzymatic Properties of S-Adenosylmethionine Synthetase from the Archaeon Methanococcus jannaschii

Crystallography captures catalytic steps in human methionine adenosyltransferase enzymes

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