TY - JOUR
T1 - Snapshots of catalysis
T2 - Structure of covalently bound substrate trapped in Mycobacterium tuberculosis thiazole synthase (ThiG)
AU - Zhang, Jia
AU - Zhang, Bing
AU - Zhao, Yao
AU - Yang, Xiuna
AU - Huang, Min
AU - Cui, Peng
AU - Zhang, Wenhong
AU - Li, Jun
AU - Zhang, Ying
N1 - Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/2/26
Y1 - 2018/2/26
N2 - Increasing drug resistance in Mycobacterium tuberculosis (Mtb) has necessitated the design of new anti-mycobacterial drugs with novel targets. Thiazole synthase (ThiG) is an essential enzyme and a potential drug target in Mtb that catalyzes the formation of the thiazole moiety of thiamin-pyrophosphate from 1-deoxy-D-xylulose-5-phosphate (DXP), dehydroglycine and ThiS-thiocarboxylate. To uncover the catalysis mechanism and design potent and selective anti-mycobacterial compounds targeting ThiG, we determined the crystal structure of MtbThiG at 1.5 Å resolution, for the first time, snapshotting a covalently bound substrate trapped in the catalytic pocket. The structure showed a (β/α)8 barrel overall fold as well as the dimer form of MtbThiG existing in solution. In the central pocket, Lys98 is the key residue forming a protonated carbinolamine intermediate, a functional Schiff base precursor, with DXP. The carbinolamine is further stabilized by active site residues mainly through hydrogen bonds. This work revealed that a protonated carbinolamine is initially formed and then it is dehydrated to the imine form of Schiff base during the early catalysis steps. Our research will provide useful information for understanding the ThiG function and lay the basis for future drug design by targeting this essential protein.
AB - Increasing drug resistance in Mycobacterium tuberculosis (Mtb) has necessitated the design of new anti-mycobacterial drugs with novel targets. Thiazole synthase (ThiG) is an essential enzyme and a potential drug target in Mtb that catalyzes the formation of the thiazole moiety of thiamin-pyrophosphate from 1-deoxy-D-xylulose-5-phosphate (DXP), dehydroglycine and ThiS-thiocarboxylate. To uncover the catalysis mechanism and design potent and selective anti-mycobacterial compounds targeting ThiG, we determined the crystal structure of MtbThiG at 1.5 Å resolution, for the first time, snapshotting a covalently bound substrate trapped in the catalytic pocket. The structure showed a (β/α)8 barrel overall fold as well as the dimer form of MtbThiG existing in solution. In the central pocket, Lys98 is the key residue forming a protonated carbinolamine intermediate, a functional Schiff base precursor, with DXP. The carbinolamine is further stabilized by active site residues mainly through hydrogen bonds. This work revealed that a protonated carbinolamine is initially formed and then it is dehydrated to the imine form of Schiff base during the early catalysis steps. Our research will provide useful information for understanding the ThiG function and lay the basis for future drug design by targeting this essential protein.
KW - Carbinolamine intermediate
KW - Covalently bound
KW - Crystal structure
KW - Mycobacterium tuberculosis
KW - Thiazole synthase
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U2 - 10.1016/j.bbrc.2018.02.056
DO - 10.1016/j.bbrc.2018.02.056
M3 - Article
C2 - 29428731
AN - SCOPUS:85042599675
SN - 0006-291X
VL - 497
SP - 214
EP - 219
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 1
ER -