title: Molecular cloning and functional analysis of squalene synthase (SS) in Panax notoginseng.
abstract: Panax notoginseng (Burk.) F. H. Chen, which is a used traditional Chinese medicine known as Sanqi or Tianqi in China, is widely studied for its ability to accumulate the triterpene saponins. Squalene synthase (SS: EC 2.5.1.21) catalyzes the first enzymatic step from the central isoprenoid pathway toward sterol and triterpenoid biosynthesis. In this study, SS from P. notoginseng was cloned and investigated followed by its recombinant expression and preliminary enzyme activity. The nucleotide sequence of the ORF contains 1 248 nucleotides and encodes 415 amino acid residues with molecular weight of 47.16kDa and pI of 6.50. Bioinformatics analysis revealed that the deduced PnSS protein had a high similarity with other plant squalene synthases. To obtain soluble recombinant enzymes, 29 hydrophobic amino acids were deleted from the carboxy terminus and expressed as GST-Tag fusion protein in Escherichia coli BL21 (DE3). Approximately 66.46kDa recombinant protein was checked on SDS-PAGE and Western Blot analysis. Preliminary activity of the resultant bacterial crude extract was analyzed by gas chromatograph-mass spectrometer (GC-MS). The identification and function of PnSS is important for further studies of the triterpene saponins biosynthesis in P. notoginseng.
authors.affiliation: School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing 100102, China; State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Jiang
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Qixian
authors.initials: Q
authors.lastname: Rong
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China; Jiangxi University of Traditional Chinese Medicine, Jiangxi, 330004, China.
authors.forename: Yijun
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Qingjun
authors.initials: Q
authors.lastname: Yuan
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Shen
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Guo
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Yirui
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Liangping
authors.initials: L
authors.lastname: Zha
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
authors.forename: Huixiao
authors.initials: H
authors.lastname: Wu
authors.affiliation: State Key Laboratory Breeding Base of Dao-di Herbs, National Resource 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
authors.affiliation: School of Chinese Pharmacy, Beijing University of Chinese Medicine, Beijing 100102, China. Electronic address: max_liucs@263.net.
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D053723:Panax notoginseng / Q000201:enzymology* / Q000235:genetics*; D010802:Phylogeny; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D013186:Farnesyl-Diphosphate Farnesyltransferase
keywords: Functional characterization; Panax notoginseng; Squalene synthase