title: [Researches on influence of squalene synthase gene polymorphism on catalytic efficiency of its encode enzyme in Glycyrrhiza uralensis].
abstract: OBJECTIVE
  To analyse the polymorphism of squalene synthase gene and reveal the influence of squalene synthase (SQS) gene polymorphism on the catalytic efficiency of its encode enzyme in Glycyrrhiza uralensi.
  
  
  METHODS
  The total RNA was extracted. PCR was used to amplify the coding sequences of squalene synthase gene, which were sequenced and analysed. The expression vectors containing different SQS gene sequences, including SQS1C, SQS1F, SQS2A, SQS2B, were constructed and transformed into Escherichia coli BL21. The fusion protein was induced to express by IPTG, then was isolated, purified and used to carry out the enzymatic reaction in vitro. GC-MS was used to analyse the production.
  
  
  RESULTS
  There were three kinds of gene polymorphism existing in SQS1 gene of G. uralensis, including single nucleotide polymorphism (SNPs), insertion/deletion length polymorphism (InDels) and level of amino acid, the proportion of conservative replace of SQS1 was 53.94%, and there were 2 mutational sites in structural domains. The proportion of conservative replace of SQS2 was 60%, and there was 1 mutational site in structural domains. The production squalene could be detected by GC-MS in all the 4 kinds of enzymatic reactions. The capacity of accumulating squalene of SQS1F was higher than other SQS genes.
  
  
  CONCLUSIONS
  The polymorphism of SQS gene was quite abundant in G. uralensis, which maybe the molecular foundation of the formation of high-quality liquorice.
authors.affiliation: School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China. liuyliwd@vip.sina.com
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Xue-Yong
authors.initials: XY
authors.lastname: Wang
authors.forename: Chun-Sheng
authors.initials: CS
authors.lastname: Liu
authors.forename: Hong-Hao
authors.initials: HH
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Wen
mesh_terms: D019943:Amino Acid Substitution; D055162:Biocatalysis; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D013186:Farnesyl-Diphosphate Farnesyltransferase / Q000235:genetics* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D029882:Glycyrrhiza uralensis / Q000201:enzymology / Q000235:genetics*; D054643:INDEL Mutation; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011110:Polymorphism, Genetic; D020641:Polymorphism, Single Nucleotide; D011994:Recombinant Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013185:Squalene / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D010940:Plant Proteins; D011994:Recombinant Proteins; D013185:Squalene; D013186:Farnesyl-Diphosphate Farnesyltransferase