Publications

• Methionine catabolism in Arabidopsis cells is initiated by a gamma-cleavage process and leads to S-methylcysteine and isoleucine syntheses.

  Rebeille F., Jabrin S., Bligny R., Loizeau K., Gambonnet B., Van Wilder V., Douce R., Ravanel S.

  Despite recent progress in elucidating the regulation of methionine (Met) synthesis, little is known about the catabolism of this amino acid in plants. In this article, we present several lines of evidence indicating that the cleavage of Met catalyzed by Met gamma-lyase is the first step in this p ... >> More

  Despite recent progress in elucidating the regulation of methionine (Met) synthesis, little is known about the catabolism of this amino acid in plants. In this article, we present several lines of evidence indicating that the cleavage of Met catalyzed by Met gamma-lyase is the first step in this process. First, we cloned an Arabidopsis cDNA coding a functional Met gamma-lyase (AtMGL), a cytosolic enzyme catalyzing the conversion of Met into methanethiol, alpha-ketobutyrate, and ammonia. AtMGL is present in all of the Arabidopsis organs and tissues analyzed, except in quiescent dry mature seeds, thus suggesting that AtMGL is involved in the regulation of Met homeostasis in various situations. Also, we demonstrated that the expression of AtMGL was induced in Arabidopsis cells in response to high Met levels, probably to bypass the elevated Km of the enzyme for Met. Second, [13C]-NMR profiling of Arabidopsis cells fed with [13C]Met allowed us to identify labeled S-adenosylmethionine, S-methylmethionine, S-methylcysteine (SMC), and isoleucine (Ile). The unexpected production of SMC and Ile was directly associated to the function of Met gamma-lyase. Indeed, we showed that part of the methanethiol produced during Met cleavage could react with an activated form of serine to produce SMC. The second product of Met cleavage, alpha-ketobutyrate, entered the pathway of Ile synthesis in plastids. Together, these data indicate that Met catabolism in Arabidopsis cells is initiated by a gamma-cleavage process and can result in the formation of the essential amino acid Ile and a potential storage form for sulfide or methyl groups, SMC. << Less

  Proc. Natl. Acad. Sci. U.S.A. 103:15687-15692(2006) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• Functional characterization of a methionine gamma-lyase in Arabidopsis and its implication in an alternative to the reverse trans-sulfuration pathway.

  Goyer A., Collakova E., Shachar-Hill Y., Hanson A.D.

  Methionine gamma-lyase (MGL) catalyzes the degradation of L-methionine to alpha-ketobutyrate, methanethiol and ammonia. The Arabidopsis (Arabidopsis thaliana) genome includes a single gene (At1g64660) encoding a protein (AtMGL) with approximately 35% identity to bacterial and protozoan MGLs. When ... >> More

  Methionine gamma-lyase (MGL) catalyzes the degradation of L-methionine to alpha-ketobutyrate, methanethiol and ammonia. The Arabidopsis (Arabidopsis thaliana) genome includes a single gene (At1g64660) encoding a protein (AtMGL) with approximately 35% identity to bacterial and protozoan MGLs. When overexpressed in Escherichia coli, AtMGL allowed growth on L-methionine as sole nitrogen source and conferred a high rate of methanethiol emission. The purified recombinant protein exhibited a spectrum typical of pyridoxal 5'-phosphate enzymes, and had high activity toward l-methionine, L-ethionine, L-homocysteine and seleno-L-methionine, but not L-cysteine. Quantitation of mRNA showed that the AtMGL gene is expressed in aerial organs and roots, and that its expression in leaves was increased 2.5-fold by growth on low sulfate medium. Emission of methanethiol from Arabidopsis plants supplied with 10 mM L-methionine was undetectable (<0.5 nmol min(-1) g(-1) FW), suggesting that AtMGL is not an important source of volatile methanethiol. Knocking out the AtMGL gene significantly increased leaf methionine content (9.2-fold) and leaf and root S-methylmethionine content (4.7- and 7-fold, respectively) under conditions of sulfate starvation, indicating that AtMGL carries a significant flux in vivo. In Arabidopsis plantlets fed L-[(35)S]methionine on a low sulfate medium, label was incorporated into protein-bound cysteine as well as methionine, but incorporation into cysteine was significantly (30%) less in the knockout mutant. These data indicate that plants possess an alternative to the reverse trans-sulfuration pathway (methionine-->homocysteine-->cystathionine-->cysteine) in which methanethiol is an intermediate. << Less

  Plant Cell Physiol. 48:232-242(2007) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• The role of amino acid residues in the active site of L-methionine gamma-lyase from Pseudomonas putida.

  Fukumoto M., Kudou D., Murano S., Shiba T., Sato D., Tamura T., Harada S., Inagaki K.

  Cys116, Lys240*, and Asp241* (asterisks indicate residues from the second subunit of the active dimer) at the active site of L-methionine γ-lyase of Pseudomonas putida (MGL_Pp) are highly conserved among heterologous MGLs. In a previous study, we found that substitution of Cys116 for His led to a ... >> More

  Cys116, Lys240*, and Asp241* (asterisks indicate residues from the second subunit of the active dimer) at the active site of L-methionine γ-lyase of Pseudomonas putida (MGL_Pp) are highly conserved among heterologous MGLs. In a previous study, we found that substitution of Cys116 for His led to a drastic increase in activity toward L-cysteine and a decrease in that toward L-methionine. In this study, we examined some properties of the C116H mutant by kinetic analysis and 3D structural analysis. We assumed that substitution of Cys116 for His broke the original hydrogen-bond network and that this induced a significant effect of Tyr114 as a general acid catalyst, possibly due to the narrow space in the active site. The C116H mutant acquired a novel β-elimination activity and lead a drastic conformation change in the histidine residue at position 116 by binding the substrate, suggesting that this His residue affects the reaction specificity of C116H. Furthermore, we suggest that Lys240* is important for substrate recognition and structural stability and that Asp241* is also involved in substrate specificity in the elimination reaction. Based on this, we suggest that the hydrogen-bond network among Cys116, Lys240*, and Asp241* contributes to substrate specificity that is, to L-methionine recognition at the active site in MGL_Pp. << Less

  Biosci. Biotechnol. Biochem. 76:1275-1284(2012) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• High production of methyl mercaptan by L-methionine-alpha-deamino-gamma-mercaptomethane lyase from Treponema denticola.

  Fukamachi H., Nakano Y., Okano S., Shibata Y., Abiko Y., Yamashita Y.

  Methyl mercaptan is derived from l-methionine by the action of l-methionine-alpha-deamino-gamma-mercaptomethane lyase (METase) and is a major component of oral malodor. This compound is highly toxic and is thought to play an important role in periodontal disease. We found that Treponema denticola, ... >> More

  Methyl mercaptan is derived from l-methionine by the action of l-methionine-alpha-deamino-gamma-mercaptomethane lyase (METase) and is a major component of oral malodor. This compound is highly toxic and is thought to play an important role in periodontal disease. We found that Treponema denticola, a member of the subgingival biofilm at periodontal disease sites, produced a large amount of methyl mercaptan even at low concentration of l-methionine. METase activity in a cell-free extract from T. denticola was detected by two-dimensional electrophoresis under non-denaturing conditions, and the protein spot that exhibited high METase activity was identified using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The identified gene produced a METase with a K(m) value for l-methionine (0.55mM) that is much lower than those of METases previously identified in the other organisms. This result suggests that T. denticola is an important producer of methyl mercaptan in the subgingival biofilm. << Less

  Biochem. Biophys. Res. Commun. 331:127-131(2005) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• 3-Chloro-DL-alanine resistance by L-methionine-alpha-deamino-gamma-mercaptomethane-lyase activity.

  Yoshimura M., Nakano Y., Fukamachi H., Koga T.

  The antibacterial agent 3-chloro-DL-alanine (3CA) is an inhibitor of peptidoglycan synthesis. Fusobacterium nucleatum and Porphyromonas gingivalis, the bacteria responsible for oral malodor, are shown to be resistant to 1 mM 3CA, whereas Streptococcus mutans and Escherichia coli are sensitive to t ... >> More

  The antibacterial agent 3-chloro-DL-alanine (3CA) is an inhibitor of peptidoglycan synthesis. Fusobacterium nucleatum and Porphyromonas gingivalis, the bacteria responsible for oral malodor, are shown to be resistant to 1 mM 3CA, whereas Streptococcus mutans and Escherichia coli are sensitive to this antibacterial agent at the same concentration. We isolated the 3CA resistance gene from F. nucleatum and showed that the gene encodes an L-methionine-alpha-deamino-gamma-mercaptomethane-lyase that catalyzes the alpha,gamma-elimination of L-methionine to produce methyl mercaptan. The enzyme also exhibits 3CA chloride-lyase (deaminating) activity. This antibacterial agent is expected to be useful for specific selection of malodorous oral bacteria producing high amounts of methyl mercaptan. << Less

  FEBS Lett. 523:119-122(2002) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Purification of bacterial L-methionine gamma-lyase.

  Nakayama T., Esaki N., Sugie K., Beresov T.T., Tanaka H., Soda K.

  A rapid procedure for the purification of L-methionine gamma-lyase from Pseudomonas putida ICR 3460 by DEAE-TOYOPEARL 650M and DEAE-Sephadex A-50 column chromatography is presented. The enzyme was purified with an average yield of 75% and showed about 10-fold higher specific activity than the enzy ... >> More

  A rapid procedure for the purification of L-methionine gamma-lyase from Pseudomonas putida ICR 3460 by DEAE-TOYOPEARL 650M and DEAE-Sephadex A-50 column chromatography is presented. The enzyme was purified with an average yield of 75% and showed about 10-fold higher specific activity than the enzyme from P. putida (= P. ovalis) IFO 3738 reported previously (H. Tanaka, N. Esaki , and K. Soda (1976) FEBS Lett. 66, 307-311). The present enzyme has a molecular weight of about 172,000 and consists of four subunits with identical molecular weights (43,000). It shows the typical absorption spectrum of pyridoxal enzyme with maxima at 278 and 420 nm, and contains 4 mol of pyridoxal 5'-phosphate per mole of enzyme. The enzyme has a multicatalytic function similar to the enzyme of P. putida IFO 3738 (K. Soda, H. Tanaka, and N. Esaki (1983) Trends Biochem. Sci. 8, 214-217). << Less

  Anal. Biochem. 138:421-424(1984) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Formation of methyl mercaptan from L-methionine by Porphyromonas gingivalis.

  Yoshimura M., Nakano Y., Yamashita Y., Oho T., Saito T., Koga T.

  Methyl mercaptan production by oral bacteria is thought to be one of the main causes of oral malodor. We examined the ability of periodontopathic Porphyromonas gingivalis to produce methyl mercaptan from L-methionine and found that the invasive strains W83 and W50 produced large amounts of methyl ... >> More

  Methyl mercaptan production by oral bacteria is thought to be one of the main causes of oral malodor. We examined the ability of periodontopathic Porphyromonas gingivalis to produce methyl mercaptan from L-methionine and found that the invasive strains W83 and W50 produced large amounts of methyl mercaptan. We cloned and sequenced the mgl gene encoding L-methionine-alpha-deamino-gamma-mercaptomethane-lyase (METase) from P. gingivalis W83. The structural mgl gene consisted of 1,200 bp and encoded a 43.3-kDa protein. To examine the role of methyl mercaptan in the pathogenesis of P. gingivalis, a METase-deficient mutant of P. gingivalis W83 was constructed. The methionine degradation activity and virulence of the mutant (M1217) and the parent strain (W83) in mice were compared. M1217 showed a marked decrease in the formation of methyl mercaptan from L-methionine and decreased virulence compared with the wild-type strain W83. These results suggest that methyl mercaptan not only is one of the sources of oral malodor, but may also play a role in the pathogenicity of P. gingivalis. << Less

  Infect. Immun. 68:6912-6916(2000) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.