文献类型：期刊文献

英文题名：Characterization and application of fusidane antibiotic biosynethsis enzyme 3-ketosteroid-Δ1-dehydrogenase in steroid transformation

作者：Chen, Miao-Miao[1]; Wang, Feng-Qing[1]; Lin, Liang-Cai[1]; Yao, Kang[1]; Wei, Dong-Zhi[1]

机构：[1] State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, China

年份：2012

卷号：96

期号：1

起止页码：133

外文期刊名：Applied Microbiology and Biotechnology

收录：EI(收录号：20123715436925)

语种：英文

外文关键词：Cytology - Escherichia coli - Amino acids - Steroid hormones - Biochemistry - Aspergillus - Cell membranes - Enzymes

摘要：Microbial Δ 1 -dehydrogenation is one of the most important transformations in the synthesis of steroid hormones. In this study, a 3-ketosteroid-Δ1-dehydrogenase (kstDF) involved in fusidane antibiotic biosynthesis from Aspergillus fumigatus CICC 40167 was characterized for use in steroid transformation. KstDF encodes a polypeptide consisting of 637 amino acid residues. It shows 51% amino acid identity with a kstD from Thermomicrobium roseum DSM 5159. Expression of kstDF in Escherichia coli and Pichia pastoris showed that all kstDF activity is located in the cytoplasm. This indicates that it is a soluble intracytoplasmic enzyme, unlike most kstDs from bacteria, which are membrane-bound. The expression of kstDF was performed in P. pastoris, both intracellularly and extracelluarly. The intracellularly expressed protein displayed good activity in steroid transformation, while the extracellularly expressed protein showed nothing. Interestingly, the engineered P. pastoris KM71 (KM71I) and GS115 (GS115I) showed different transformation activities for 4-androstene-3,17-dione (AD) when kstDF was expressed intracellularly. Under the same conditions, KM71I was found capable of transforming 1.0 g/l AD to 1,4-androstadiene-3,17-dione (ADD), while GS115I could transform 1.5 g/l AD to both ADD and boldenone (BD). The production of BD is attributed to a 17β-hydroxysteroid dehydrogenase in P. pastoris GS115I, which catalyzes the reversible reaction between C17-one and C17-alcohol of steroids. The conversion of AD by GS115I and KM71I may provide alternative means of preparing ADD or BD. In brief, we show here that kstDF is a promising enzyme in steroid Δ 1 -dehydrogenation that is propitious to construct genetically engineered steroid-transforming recombinants by heterologous overexpression. ? 2012 Springer-Verlag.