Mycothiol‐Dependent Formaldehyde Dehydrogenase, A Prokaryotic Medium‐Chain Dehydrogenase/Reductase, Phylogenetically Links Different Eukaroytic Alcohol Dehydrogenases Primary Structure, Conformational Modelling and Functional Correlations

Norin, Annika; Ophem, Peter W. van; Piersma, Sander R.; Persson, Bengt; Duine, Johannis A.; Jörnvall, Hans

doi:10.1111/j.1432-1033.1997.00282.x

Cited by 47 publications

(49 citation statements)

References 39 publications

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“…Sequence analysis showed that the enzyme is a divergent medium-chain dehydrogenase/reductase (103). The cloned His 6 -tagged M. tuberculosis enzyme proved difficult to purify in active form when expressed in E. coli or M. smegmatis (149).…”

Section: Mscr Msno Reductase/formaldehyde Dehydrogenasementioning

confidence: 99%

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Biosynthesis and Functions of Mycothiol, the Unique Protective Thiol of Actinobacteria

Newton

Buchmeier

Fahey

2008

Microbiol Mol Biol Rev

313

293

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SUMMARY Mycothiol (MSH; AcCys-GlcN-Ins) is the major thiol found in Actinobacteria and has many of the functions of glutathione, which is the dominant thiol in other bacteria and eukaryotes but is absent in Actinobacteria. MSH functions as a protected reserve of cysteine and in the detoxification of alkylating agents, reactive oxygen and nitrogen species, and antibiotics. MSH also acts as a thiol buffer which is important in maintaining the highly reducing environment within the cell and protecting against disulfide stress. The pathway of MSH biosynthesis involves production of GlcNAc-Ins-P by MSH glycosyltransferase (MshA), dephosphorylation by the MSH phosphatase MshA2 (not yet identified), deacetylation by MshB to produce GlcN-Ins, linkage to Cys by the MSH ligase MshC, and acetylation by MSH synthase (MshD), yielding MSH. Studies of MSH mutants have shown that the MSH glycosyltransferase MshA and the MSH ligase MshC are required for MSH production, whereas mutants in the MSH deacetylase MshB and the acetyltransferase (MSH synthase) MshD produce some MSH and/or a closely related thiol. Current evidence indicates that MSH biosynthesis is controlled by transcriptional regulation mediated by σB and σR in Streptomyces coelicolor. Identified enzymes of MSH metabolism include mycothione reductase (disulfide reductase; Mtr), the S-nitrosomycothiol reductase MscR, the MSH S-conjugate amidase Mca, and an MSH-dependent maleylpyruvate isomerase. Mca cleaves MSH S-conjugates to generate mercapturic acids (AcCySR), excreted from the cell, and GlcN-Ins, used for resynthesis of MSH. The phenotypes of MSH-deficient mutants indicate the occurrence of one or more MSH-dependent S-transferases, peroxidases, and mycoredoxins, which are important targets for future studies. Current evidence suggests that several MSH biosynthetic and metabolic enzymes are potential targets for drugs against tuberculosis. The functions of MSH in antibiotic-producing streptomycetes and in bioremediation are areas for future study.

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Section: Mscr Msno Reductase/formaldehyde Dehydrogenasementioning

confidence: 99%

“…8. MSH reacts spontaneously with formaldehyde to produce an adduct, H 2 C(OH)SM, which is a substrate for the formaldehyde dehydrogenase AdhE2 (103). AdhE2-catalyzed oxidation of formaldehyde to formate detoxifies formaldehyde originating from metabolic or environmental sources.…”

Section: Overviewmentioning

confidence: 99%

Biosynthesis and Functions of Mycothiol, the Unique Protective Thiol of Actinobacteria

Newton

Buchmeier

Fahey

2008

Microbiol Mol Biol Rev

313

293

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“…8) S-Hydroxymethyl-mycothiol is formed nonenzymatically from mycothiol and formaldehyde in Gram-positive methylotrophs; mFADH then catalyzes NAD-dependent dehydrogenation of S-hydroxymethylmycothiol to produce S-formyl-mycothiol. 9) The genetic organization in the vicinity of the mFADH gene in the N9T-4 genome was compared with that in the R. erythropolis PR4 and R. jostii RHA1 genomes 10) which have been completely sequenced (Fig. 1a).…”

Section: Resultsmentioning

confidence: 99%

Gene Expression Analysis of Methylotrophic Oxidoreductases Involved in the Oligotrophic Growth ofRhodococcus erythropolisN9T-4

Yoshida

Hayasaki

Takagi

2011

Bioscience, Biotechnology, and Biochemistry

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“…The first was for MSH-dependent formaldehyde dehydrogenase of Amycolatopsis methanolica (8,16), whose protein sequence is 80% identical to Rv2259 of M. tuberculosis (Sanger Centre). A disulfide reductase (Rv2855) initially designated as a glutathione reductase (4) was cloned and expressed in M. smegmatis and was shown to have specificity for mycothiol disulfide, alternatively designated mycothione (17,18).…”

Section: Discussionmentioning

confidence: 99%

N -Acetyl-1- d - myo -Inosityl-2-Amino-2-Deoxy-α- d -Glucopyranoside Deacetylase (MshB) Is a Key Enzyme in Mycothiol Biosynthesis

2000

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Mycothiol is a novel thiol produced only by actinomycetes and is the major low-molecular-weight thiol in mycobacteria. Mycothiol was previously shown to be synthesized from 1-D-myo-inosityl-2-amino-2-deoxy-␣-Dglucopyranoside by ligation with cysteine followed by acetylation. A novel mycothiol-dependent detoxification enzyme, mycothiol conjugate amidase, was recently identified in Mycobacterium smegmatis and shown to have a homolog, Rv1082, in Mycobacterium tuberculosis. In the present study we found that a protein encoded by the M. tuberculosis open reading frame Rv1170, a homolog of Rv1082, possesses weak mycothiol conjugate amidase activity but shows substantial deacetylation activity with 1-D-myo-inosityl-2-acetamido-2-deoxy-␣-D-glucopyranoside (GlcNAc-Ins), a hypothetical mycothiol biosynthetic precursor. The availability of this protein enabled us to develop an assay for GlcNAc-Ins, which was used to demonstrate that GlcNAc-Ins is present in M. smegmatis at a level about twice that of mycothiol. It was shown that GlcNAc-Ins is absent in mycothiol-deficient mutant strain 49 of M. smegmatis and that this strain can concentrate GlcNAc-Ins from the medium and convert it to mycothiol. This demonstrates that GlcNAc-Ins is a key intermediate in the pathway of mycothiol biosynthesis. Assignment of Rv1170 as the gene coding the deacetylase in the M. tuberculosis genome represents the first identification of a gene of the mycothiol biosynthesis pathway. The presence of a large cellular pool of substrate for this enzyme suggests that it may be important in regulating mycothiol biosynthesis.Most gram-positive bacteria, including many strict aerobes, do not produce glutathione (7, 13), a key component of cellular mechanisms for protection against oxygen toxicity (5). In the search for other thiols in these organisms that might function like glutathione, a major thiol in streptomycetes was discovered (14) and later identified (12,19,21) as a novel conjugate of N-acetylcysteine (AcCys) and 1-D-myo-inosityl-2-amino-2-deoxy-␣-D-glucopyranoside (GlcN-Ins) producing mycothiol (MSH or AcCys-GlcN-Ins). Bornemann et al. (3) showed that chemically synthesized GlcN-Ins could be converted to CysGlcN-Ins and MSH by Mycobacterium smegmatis cell extracts in the presence of ATP, Mg 2ϩ , Cys, and acetate or acetyl coenzyme A (acetyl-CoA). They proposed that the final steps of MSH biosynthesis involve ATP-dependent ligation of Cys with GlcN-Ins, followed by acetylation via an acetyltransferase reaction involving acetyl-CoA. Measurements of GlcN-Ins and Cys-GlcN-Ins levels in M. smegmatis (1) and isolation of mutants defective in GlcN-Ins or Cys-GlcN-Ins production support the existence of this pathway (15).The earlier studies left undefined the biochemical reactions involved in GlcN-Ins formation. By analogy with the established biochemistry for production of the glycosylphosphatidylinositol (GPI) anchor, which contains as a component an isomer of GlcN-Ins with an ␣(1-6) linkage, one might expect that GlcN-Ins is produced by deacetylati...

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Mycothiol‐Dependent Formaldehyde Dehydrogenase, A Prokaryotic Medium‐Chain Dehydrogenase/Reductase, Phylogenetically Links Different Eukaroytic Alcohol Dehydrogenases Primary Structure, Conformational Modelling and Functional Correlations

Cited by 47 publications

References 39 publications

Biosynthesis and Functions of Mycothiol, the Unique Protective Thiol of Actinobacteria

Biosynthesis and Functions of Mycothiol, the Unique Protective Thiol of Actinobacteria

Gene Expression Analysis of Methylotrophic Oxidoreductases Involved in the Oligotrophic Growth ofRhodococcus erythropolisN9T-4

N -Acetyl-1- d - myo -Inosityl-2-Amino-2-Deoxy-α- d -Glucopyranoside Deacetylase (MshB) Is a Key Enzyme in Mycothiol Biosynthesis

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