title: Crystal structure of 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase (IspE) from Mycobacterium tuberculosis.
abstract: Isoprenoid precursors, which are a large group of natural products and play key roles in many biological pathways, can only be biosynthesized by the 2-C-methyl-d-erythritol 4-phosphate pathway in Mycobacterium tuberculosis. The 4-diphosphocytidyl-2-C-methyl-d-erythritol kinase (IspE), which is an essential enzyme in the isoprenoid precursor biosynthesis pathway, catalyzes ATP-dependent phosphorylation of 4-diphosphocytidyl-2-C-methyl-d-erythritol (CDP-ME) to 4-diphosphocytidyl-2C-methyl-d-erythritol-2-phosphate and plays a crucial role in M. tuberculosis survival. Therefore, IspE is characterized as an attractive and potential target for antimicrobial drug discovery. However, no experimental structure of M. tuberculosis IspE has been reported, which has hindered our understanding of its structural details and mechanism of action. Here, we report the expression and purification of fully active full-length M. tuberculosis IspE and solve the high-resolution crystal structures of IspE alone and in complex with either the substrate CDP-ME or nonhydrolyzable ATP analog or ADP. The structures present a characteristic galactose/homoserine/mevalonate/phosphomevalonate kinase superfamily α/β-fold with a catalytic center located in a cleft between 2 domains and display clear substrate and ATP binding pockets. Our results also indicate distinct differences in ligand binding of M. tuberculosis IspE with other reported IspEs. Combined with the results of mutagenesis and enzymatic studies, our results provide useful information on the structural basis of IspE for future anti-M. tuberculosis drug discovery targeting this kinase.
authors.affiliation: Structural Biology Laboratory, Tsinghua University, Beijing, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Shan
authors.forename: Xuehui
authors.initials: X
authors.lastname: Chen
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.forename: Hanchao
authors.initials: H
authors.lastname: Zhao
authors.forename: Zihe
authors.initials: Z
authors.lastname: Rao
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Lou
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray / Q000379:methods*; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor)