title: Molecular cloning and characterization of α-amylase/subtilisin inhibitor from rhizome of Ligusticum chuanxiong.
abstract: OBJECTIVE
  To clone and characterize a novel bi-functional α-amylase/subtilisin inhibitor (LASI) from the rhizome of Ligusticum chuanxiong, a traditional Chinese medicine.
  
  
  RESULTS
  The LASI showed strong homology with members of the Kunitz trypsin inhibitor family. Its putative amino acid sequence has a 40 % identity with that of the α-amylase/subtilisin inhibitor from rice. LASI gene without signal peptide was expressed in E. coli Rosetta. After purification, the recombinant LASI protein was inhibitory against not only α-amylase from porcine pancreas, Helicoverpa armigera, Spodoptera litura and Plutella xylostella, but also subtilisin A, but not against trypsin or chymotrypsin. In addition, the expression level of LASI in rhizome was higher than that in leaf and LASI expression was enhanced by salt, chilling and drought treatment.
  
  
  CONCLUSIONS
  This is the first member of the Kunitz-protease inhibitor family identified in traditional Chinese medicine and it might be involved in the plant defense responses against lepidopterous pests, microorganisms and abiotic stresses.
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Ji-Hua
authors.initials: JH
authors.lastname: Yu
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Yang-Yang
authors.initials: YY
authors.lastname: Li
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Mian
authors.initials: M
authors.lastname: Xiang
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Jian-Quan
authors.initials: JQ
authors.lastname: Zhu
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Xin-He
authors.initials: XH
authors.lastname: Huang
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Wan-Jun
authors.initials: WJ
authors.lastname: Wang
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Tan
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China. jiayzhou2014@163.com.
authors.forename: Jia-Yu
authors.initials: JY
authors.lastname: Zhou
authors.affiliation: School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, Sichuan, China. liaohai0918@163.com.
authors.forename: Hai
authors.initials: H
authors.lastname: Liao
mesh_terms: D003001:Cloning, Molecular; D004791:Enzyme Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D030004:Ligusticum / Q000378:metabolism*; D027343:Rhizome / Q000378:metabolism*; D020860:Subtilisin / Q000037:antagonists & inhibitors*; D000516:alpha-Amylases / Q000037:antagonists & inhibitors*
chemical_list: D004791:Enzyme Inhibitors; D000516:alpha-Amylases; D020860:Subtilisin
keywords: Abiotic stress; Heterologous expression; Lepidopterous pest; Microorganism; α-Amylase/Subtilisin inhibitor