title: Cross-functionalities of Bacillus deacetylases involved in bacillithiol biosynthesis and bacillithiol-S-conjugate detoxification pathways.
abstract: BshB, a key enzyme in bacillithiol biosynthesis, hydrolyses the acetyl group from N-acetylglucosamine malate to generate glucosamine malate. In Bacillus anthracis, BA1557 has been identified as the N-acetylglucosamine malate deacetylase (BshB); however, a high content of bacillithiol (~70%) was still observed in the B. anthracis ∆BA1557 strain. Genomic analysis led to the proposal that another deacetylase could exhibit cross-functionality in bacillithiol biosynthesis. In the present study, BA1557, its paralogue BA3888 and orthologous Bacillus cereus enzymes BC1534 and BC3461 have been characterized for their deacetylase activity towards N-acetylglucosamine malate, thus providing biochemical evidence for this proposal. In addition, the involvement of deacetylase enzymes is also expected in bacillithiol-detoxifying pathways through formation of S-mercapturic adducts. The kinetic analysis of bacillithiol-S-bimane conjugate favours the involvement of BA3888 as the B. anthracis bacillithiol-S-conjugate amidase (Bca). The high degree of specificity of this group of enzymes for its physiological substrate, along with their similar pH-activity profile and Zn²⁺-dependent catalytic acid-base reaction provides further evidence for their cross-functionalities.
authors.affiliation: Department of Chemistry, Wake Forest University, Winston-Salem, NC 27109, USA.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Fang
authors.forename: Alexandra A
authors.initials: AA
authors.lastname: Roberts
authors.forename: Karissa
authors.initials: K
authors.lastname: Weidman
authors.forename: Sunil V
authors.initials: SV
authors.lastname: Sharma
authors.forename: Al
authors.initials: A
authors.lastname: Claiborne
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hamilton
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Dos Santos
mesh_terms: D000107:Acetylation; D000117:Acetylglucosamine / Q000031:analogs & derivatives / Q000378:metabolism; D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001408:Bacillus anthracis / Q000201:enzymology / Q000378:metabolism*; D001409:Bacillus cereus / Q000201:enzymology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D055162:Biocatalysis; D020134:Catalytic Domain; D017124:Conserved Sequence; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008293:Malates / Q000378:metabolism; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity; D015032:Zinc / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008293:Malates; D050505:Mutant Proteins; D011994:Recombinant Proteins; C543521:bacillithiol; D000581:Amidohydrolases; C023079:N-acetylglucosamine deacetylase; D015032:Zinc; D003545:Cysteine; D005944:Glucosamine; D000117:Acetylglucosamine