Structural characterization of free-state and product-stateMycobacterium tuberculosismethionyl-tRNA synthetase reveals an induced-fit ligand-recognition mechanism
Wang, W., Qin, B., Wojdyla, J.A., Wang, M., Gao, X., Cui, S.(2018) IUCrJ 5: 478-490
- PubMed: 30002848 
- DOI: https://doi.org/10.1107/S2052252518008217
- Primary Citation of Related Structures:  
5XET, 5XGQ - PubMed Abstract: 
Mycobacterium tuberculosis (MTB) caused 10.4 million cases of tuberculosis and 1.7 million deaths in 2016. The incidence of multidrug-resistant and extensively drug-resistant MTB is becoming an increasing threat to public health and the development of novel anti-MTB drugs is urgently needed. Methionyl-tRNA synthetase (MetRS) is considered to be a valuable drug target. However, structural characterization of M. tuberculosis MetRS (MtMetRS) was lacking for decades, thus hampering drug design. Here, two high-resolution crystal structures of MtMetRS are reported: the free-state structure (apo form; 1.9 Å resolution) and a structure with the intermediate product methionyl-adenylate (Met-AMP) bound (2.4 Å resolution). It was found that free-state MtMetRS adopts a previously unseen conformation that has never been observed in other MetRS homologues. The pockets for methionine and AMP are not formed in free-state MtMetRS, suggesting that it is in a nonproductive conformation. Combining these findings suggests that MtMetRS employs an induced-fit mechanism in ligand binding. By comparison with the structure of human cytosolic MetRS, additional pockets specific to MtMetRS that could be used for anti-MTB drug design were located.
Organizational Affiliation: 
MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People's Republic of China.