Cloning and Molecular Characterization of Three Arylamine N-Acetyltransferase Genes from Bacillus anthracis: Identification of Unusual Enzymatic Properties and Their Contribution to Sulf

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• 作者：Benjamin Pluvinage ; Julien Dairou ; Odile M. Possot ; Marta Martins ; Agn&egrave ; s Fouet ; Jean-Marie Dupret ; Fernando Rodrigues-Lima
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：June 12, 2007
• 年：2007
• 卷：46
• 期：23
• 页码：7069 - 7078
• 全文大小：1019K
• 年卷期：v.46,no.23(June 12, 2007)
• ISSN：1520-4995

文摘

The arylamine N-acetyltransferases (NATs) are xenobiotic-metabolizing enzymes that catalyzethe N-acetylation of arylamines and their N-hydroxylated metabolites. These enzymes play a key role indetoxication of numerous drugs and xenobiotics. We report here the cloning, functional expression, andcharacterization of three new NAT genes (termed banatA, banatB, and banatC) from the pathogen Bacillusanthracis. The sequences of the corresponding proteins are ~30% identical with those of characterizedeukaryotic and prokaryotic NAT enzymes, and the proteins were recognized by an anti-NAT antibody.The three genes were endogenously expressed in B. anthracis, and NAT activity was found in cell extracts.The three NAT homologues exhibited distinct structural and enzymatic properties, some of which havenot previously been observed with other NAT enzymes. Recombinant BanatC displayed strong NATactivity toward several prototypic NAT substrates, including the sulfonamide antibiotic sulfamethoxazole(SMX). As opposed to BanatC, BanatB also had acetyl-CoA (AcCoA) and p-nitrophenyl acetate (PNPA)hydrolysis activity in the absence of arylamine substrates, indicating that it may act as an AcCoA hydrolase.BanatA was devoid of NAT or AcCoA/PNPA hydrolysis activities, suggesting that it may be a newbacterial NAT-like protein with unknown function. Expression of BanatC in Escherichia coli affordedhigher-than-normal resistance to SMX in the recombinant bacteria, whereas an inactive mutant of theenzyme did not. These data indicate that BanatC could contribute to the resistance of B. anthracis toSMX.