Characterization and biochemical investigation of the potential inositol monophosphate phosphatase involved in bacterial mycothiol biosynthesis

Abstract

Mycothiol (MSH) is the predominant form of small molecule thiols produced by actinomycetes and plays a pivotal role in the bacterial detoxication process. The only enzyme involved in MSH biosynthesis that has not been characterized yet is a phosphatase MshA2, which was proposed to catalyze the hydrolysis of 3-phospho-1-D-myo-inosityl-2-acetamido-2-deoxy-α-D-glucopyranoside (GlcNAc-Ins-3-P) to GlcNAc-Ins. In this study, a new inositol monophosphate phosphatase from Corynebacterium glutamicum, designated as Cg0911, was discovered, expressed and characterized. Detailed biochemical studies on Cg0911 revealed that GlcNAc-Ins-3-P was its preferred substrate for efficient conversion into GlcNAc-Ins.

Graphical Abstract

Keywords:

• Mycothiol
• MshA2
• Cg0911
• inositol monophosphatase
• Corynebacterium glutamicum

Acknowledgments

We thank Prof. Qingsheng Qi from State Key Laboratory of Microbial Technology (SKLM) for the kind gift of C. glutamicum.

Supporting material

Bacterial stains, DNA primes and vectors, sequence alignments of Cg0910 with homologous or related genes, SDS-PAGE results of recombinant proteins, and enzyme kinetics curve of Cg0911 with GlcNAc-Ins-3-P as the substrate (PDF).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [21472114] and the Science and Technology Development Project of Shandong Province [2016GGH4502].