Molecular and biochemical characterization of a novel isoprene synthase from Metrosideros polymorpha

BMC Plant Biology

Dong-Myung Kim¹  Seung-Goo Lee²  Haseong Kim²  Seong Keun Kim²  Hyewon Lee²  Soo-Jin Yeom²  Moonjung Kim²  Dae-Hee Lee²  Kil Koang Kwon² 

[1] Department of Chemical Engineering and Applied Chemistry, Chungnam National University;Synthetic Biology and Bioengineering Research Center, KRIBB;

关键词: Isoprene synthase;    DMAPP;    Escherichia coli;    Mevalonate pathway;   

DOI  :  10.1186/s12870-018-1315-4

来源: DOAJ

【 摘 要 】

Abstract Background Isoprene is a five-carbon chemical that is an important starting material for the synthesis of rubber, elastomers, and medicines. Although many plants produce huge amounts of isoprene, it is very difficult to obtain isoprene directly from plants because of its high volatility and increasing environmental regulations. Over the last decade, microorganisms have emerged as a promising alternative host for efficient and sustainable bioisoprene production. Isoprene synthase (IspS) has received much attention for the conversion of isoprene from dimethylallyl diphosphate (DMAPP). Herein, we isolated a highly expressible novel IspS gene from Metrosideros polymorpha (MpIspS), which was cloned and expressed in Escherichia coli, using a plant cDNA library and characterized its molecular and biochemical properties. Results The signal sequence deleted MpIspS was cloned and expressed in E. coli as a 65-kDa monomer. The maximal activity of the purified MpIspS was observed at pH 6.0 and 55 °C in the presence of 5 mM Mn2+. The K m, k cat, and k cat/K m for DMAPP as a substrate were 8.11 mM, 21 min− 1, and 2.59 mM− 1 min− 1, respectively. MpIspS was expressed along with the exogenous mevalonate pathway to produce isoprene in E. coli. The engineered cells produced isoprene concentrations of up to 23.3 mg/L using glycerol as the main carbon source. Conclusion MpIspS was expressed in large amounts in E. coli, which led to increased enzymatic activity and resulted in isoprene production in vivo. These results demonstrate a new IspS enzyme that is useful as a key biocatalyst for bioisoprene production in engineered microbes.

【 授权许可】

Unknown