Biophysical and functional characterizations of recombinant RimI acetyltransferase from Mycobacterium tuberculosis

查看全文 作　　者：Meijing [1]Hou;Jie [1]Zhuang;Shihui [1]Fan;Huilin [1]Wang;Chenyun [1]Guo;Hongwei [1]Yao;Donghai [1]Lin;Xinli [1]Liao 机构地区：[1]Department of Chemical Biology,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China 出　　处：《Acta Biochimica et Biophysica Sinica》索引2019年第51卷第9期,共9页 基　　金：This work was supported by the grants from the Key Research and Development Project of China(2016YFA0500600);the National Natural Science Foundation of China(81661138005,31700656,and 31670741). 摘　　要：Nα-acetylation is a universal protein modification related to a wide range of physiological processes in eukaryotes and prokaryotes. RimI, an Nα-acetyltransferase in Mycobacterium tuberculosis, is responsible for the acetylation of the α-amino group of the N-terminal residue in the ribosomal protein S18. Despite growing evidence that protein acetylation may be correlated with the pathogenesis of tuberculosis, no structural information is yet available for mechanistically understanding the MtRimI acetylation. To enable structural studies for MtRimI, we constructed a serial of recombinant MtRimI proteins and assessed their biochemical properties. We then chose an optimal construct MtRimIC21A4-153 and expressed and purified the truncated high-quality protein for further biophysical and functional characterizations. The 2D 1H-15N heteronuclear single quantum coherence spectrum of MtRimIC21A4-153 exhibits wider chemical shift dispersion and favorable peak isolation, indicating that MtRimIC21A4-153 is amendable for further structural determination. Moreover, bio-layer interferometry experiments showed that MtRimIC21A4-153 possessed similar micromolar affinity to full-length MtRimI for binding the hexapeptide substrate Ala-Arg-Tyr-Phe-Arg-Arg. Enzyme kinetic assays also exhibited that MtRimIC21A4-153 had almost identical enzymatic activity to MtRimI, indicating insignificant influence of the recombinant variations on enzymatic functions. Furthermore, binding sites of the peptide were predicted by molecular docking approach, suggesting that this substrate binds to MtRimI primarily through electrostatic and hydrogen bonding interactions. Our results lay a foundation for the further structural determination and dynamics detection of MtRimI. 关 键 词：MtRimIC21A4-153 RECOMBINANT preparation HSQC NMR bio-layer INTERFERENCE ACETYLTRANSFERASE ASSAY