The acetylation of pknH is linked to the ethambutol resistance of Mycobacterium tuberculosis.

Abstract

EmbR, a substrate of pknH in Mycobacterium tuberculosis (Mtb), is related to the ethambutol (EMB) resistance. This study aimed to investigate the relationship between acetylation of pknH and the resistance of EMB mono-resistant Mtb. The EMB mono-resistant Mtb strain was constructed based on the MYCOTB and the Löwenstein-Jensen (LJ) proportion method. The growth kinetics was used to evaluate the bacterial growth. Escherichia coli, as the host of Mtb, was used for cloning and protein purification. Moreover, the immunoprecipitation was performed along with western blot to evaluate the EmbR phosphorylation and pknH acetylation. Each independent experiment was conducted in triplicate. EMB mono-resistant Mtb strain was successfully constructed according to the results of MIC values of 14 anti-Mtb drugs. The EMB resistant (ER) Mtb strain showed faster growth than the wild-type (WT) Mtb strain, and the difference was statistically significant. Moreover, pknH robustly phosphorylates EmbR, and pknH and acetylated pknH protein levels were downregulated in ER strain. The acetylation of pknH may reduce the phosphorylation of EmbR to inhibit the growth of Mtb strain. Enhancing the acetylation of pknH may be a promising method to inhibit the EMB resistance against Mtb.