Rv3400 is a phosphoglucomutase required for trehalose metabolism in Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) causes over 1 million deaths from tuberculosis (TB) every year and remains a major burden on human health. Reducing the deadly impact of TB requires a better understanding of the strategies used by M. tuberculosis to adapt its metabolism, survive, and persist in the human host. Previous enzymological studies reported that the Mtb rv3400 gene encodes a β-phosphoglucomutase; however, its role in M. tuberculosis metabolism had not been investigated. Here, we show that deletion of rv3400 causes a 30-fold increase in β-D-glucose-1-phosphate, confirming its primary function as a β-phosphoglucomutase. Deletion of rv3400 also causes a growth defect when trehalose is the sole carbon source. Targeted metabolomics revealed that metabolites associated with redox homeostasis, including ergothioneine, mycothiol, and mycothione, are decreased in the Mtb Δrv3400 strain compared with the wild type, indicating altered tolerance to redox stress. Consistent with this, the Δrv3400 strain showed increased susceptibility to oxidative stress induced by H₂O₂ and cumene hydroperoxide, conditions that Mtb encounters during infection. This work advances our understanding of trehalose metabolism in Mtb and suggests that Rv3400 may represent a target for the development of new antimicrobial therapies.

Trehalose metabolism plays a cornerstone role in Mycobacterium tuberculosis physiology and virulence. A better understanding of the metabolism of this essential disaccharide is therefore required to develop new strategies to eradicate tuberculosis. Here, we characterize M. tuberculosis lacking the β-phosphoglucomutase encoded by rv3400. We show that deletion of rv3400 leads to accumulation of β-D-glucose-1-phosphate, impaired growth when trehalose is used as the sole carbon source, and increased susceptibility to oxidative stress. Taken together, these data provide evidence that Rv3400 is required for optimal catabolism of trehalose.