title: Cloning, prokaryotic expression and functional analysis of squalene synthase (SQS) in Magnolia officinalis.
abstract: Magnolia officinalis Rehder et Wilson is a traditional Chinese herbal medicine that is used to treat various diseases such as neurosis, anxiety, and stroke. The main secondary metabolites in magnolia bark are phenolic compounds and terpenoids. Squalene synthase plays a significant role in catalyzing two farnesyl diphosphate molecules to form squalene, the first precursor of triterpenoid, phytosterol, and cholesterol biosynthesis. In this study, a full-length cDNA of squalene synthase was cloned from M. officinalis and designated MoSQS (GenBank accession no. KT223496). The gene contains a 1240-bp open reading frame and it encodes a protein with 409 amino acids. Bioinformatic and phylogenetic analysis clearly suggested that MoSQS shared high similarity with squalene synthases among other plants. Prokaryotic expression showed that a transmembrane domain-deleted (385-409 aa) MoSQS mutant (MoSQSΔTM) could be expressed in its soluble form in Escherichia coli Transetta (DE3). GC-MS analysis showed that squalene was detected in an in vitro reaction mixture. These results indicated that MoSQSΔTM was functional, thereby establishing an important foundation for the study of triterpenoid biosynthesis in M. officinalis.
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resources Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; Pharmacy College, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
authors.forename: Liangping
authors.initials: L
authors.lastname: Zha
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resources Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing 100102, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resources Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Su
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resources Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China. Electronic address: y_yuan0732@163.com.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resources Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China. Electronic address: huangluqi01@126.com.
authors.forename: Luqi
authors.initials: L
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000235:genetics / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D015870:Gene Expression; D031566:Magnolia / Q000201:enzymology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D013186:Farnesyl-Diphosphate Farnesyltransferase
keywords: Magnolia officinalis; Prokaryotic expression; Squalene synthase; Terpenoids