title: Purification and characterization of Mycobacterium tuberculosis 1D-myo-inosityl-2-acetamido-2-deoxy-alpha-D-glucopyranoside deacetylase, MshB, a mycothiol biosynthetic enzyme.
abstract: Mycothiol (MSH, AcCys-GlcN-Ins) is the major low molecular weight thiol in actinomycetes and is essential for growth of Mycobacterium tuberculosis. MshB, the GlcNAc-Ins deacetylase, is a key enzyme in MSH biosynthesis. MshB from M. tuberculosis was cloned, expressed, purified, and its properties characterized. Values of k(cat) and K(m) for MshB were determined for the biological substrate, GlcNAc-Ins, and several other good substrates. The substrate specificity of MshB was compared to that of M. tuberculosis mycothiol S-conjugate amidase (Mca), a homologous enzyme having weak GlcNAc-Ins deacetylase activity. Both enzymes are metalloamidases with overlapping amidase activity toward mycothiol S-conjugates (AcCySR-GlcN-Ins). The Ins residue and hydrophobic R groups enhance the activity with both MshB and Mca, but changes in the acyl group attached to GlcN have opposite effects on the two enzymes.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, 92093, USA.
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Newton
authors.forename: Mary
authors.initials: M
authors.lastname: Ko
authors.forename: Philong
authors.initials: P
authors.lastname: Ta
authors.forename: Yossef
authors.initials: Y
authors.lastname: Av-Gay
authors.forename: Robert C
authors.initials: RC
authors.lastname: Fahey
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D003545:Cysteine; D004187:Disaccharides / Q000096:biosynthesis; D006020:Glycopeptides; D007294:Inositol; D008667:Metalloproteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000201:enzymology*; D011720:Pyrazoles; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013438:Sulfhydryl Compounds
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D006020:Glycopeptides; D008667:Metalloproteins; D011720:Pyrazoles; D011994:Recombinant Proteins; D013438:Sulfhydryl Compounds; C089265:mycothiol; D007294:Inositol; D000581:Amidohydrolases; C417275:N-acetyl-1-D-inosityl-2-amino-2-deoxy-alpha-D-glucopyranoside deacetylase; C019665:amidase; D003545:Cysteine