Structural analysis of the housecleaning nucleoside triphosphate pyrophosphohydrolase MazG from Mycobacterium tuberculosis

Abstract

The housecleaning enzyme of Mycobacterium tuberculosis (Mtb), MazG, is a nucleoside triphosphate pyrophosphohydrolase (NTP-PPase) and can hydrolyze all canonical or non-canonical NTPs into NMPs and pyrophosphate. The Mycobacterium tuberculosis MazG (Mtb-MazG) contributes to antibiotic resistance in response to oxidative or nitrosative stress under dormancy, making it a promising target for treating TB in latent infection patients. However, the structural basis of Mtb-MazG is not clear. Here we describe the crystal structure of Mtb-MazG (1–185) at 2.7 Å resolution, composed of two similar folded spherical domains in tandem. Unlike other all-α NTP pyrophosphatases, Mtb-MazG has an N-terminal extra region composed of three α-helices and five β-strands. The second domain is global, with five α-helices located in the N-terminal domain. Gel-filtration assay and SAXS analysis show that Mtb-MazG forms an enzyme-active dimer in solution. In addition, the metal ion Mg2+ is bound with four negative-charged residues Glu119, Glu122, Glu138, and Asp141. Different truncations and site-directed mutagenesis revealed that the full-length dimeric form and the metal ion Mg2+ are indispensable for the catalytic activity of Mtb-MazG. Thus, our work provides new insights into understanding the molecular basis of Mtb-MazG.

The Structural and Molecular Mechanisms of Mycobacterium tuberculosis Translational Elongation Factor Proteins

“…The structures of several key proteins of Mtb have been elucidated, e.g., membrane transporter MmpL3 [82,83], RNase J [84], fatty acyl-AMP ligase FadD32 [85], acetyltransferase Eis [86], EF-Tu/EF-Ts [49], EF-G [68], and nucleoside triphosphate pyrophosphohydrolase MazG [87]. Inhibitors of these proteins are considered promising for the treatment of tuberculosis, among which 11 potential anti-tuberculosis drugs have been obtained by Li et al, based on the rational drug of acetyltransferase Eis [86].…”

Expression of human dCTP pyrophosphatase 1 (DCTPP1) and its association with cisplatin resistance characteristics in ovarian cancer

“…Nucleotide triphosphate pyrophosphate hydrolase (NTP‐PPase) can hydrolyze the phosphate diester bond of nucleoside triphosphate dNTP to form nucleoside monophosphate dNMP, releasing pyrophosphate. 7 , 8 , 9 The hydrolysis of abnormal nucleotides by NTP‐PPase significantly reduces the number of abnormal nucleotides in the cell nucleotide pool, avoids the incorporation of abnormal nucleotides during DNA synthesis and improves the accuracy of DNA replication. 7 , 8 , 10 , 11 …”

“… 7 , 8 , 9 The hydrolysis of abnormal nucleotides by NTP‐PPase significantly reduces the number of abnormal nucleotides in the cell nucleotide pool, avoids the incorporation of abnormal nucleotides during DNA synthesis and improves the accuracy of DNA replication. 7 , 8 , 10 , 11 …”