title: Recombinant omega-conotoxin MVIIA possesses strong analgesic activity.
abstract: BACKGROUND
  omega-Conotoxin (CTX) MVIIA is a specific antagonist of N-type voltage-sensitive calcium channels. A synthetic peptide version of CTX MVIIA (ziconotide) has been approved by the US FDA for severe and chronic pain. Given the high cost and complexity of the synthetic process of the disulfide-rich peptide, the genetic recombinant approach may simplify the development of this potent therapeutic agent.
  
  
  OBJECTIVE
  In this study, we report a new method for production of the recombinant CTX MVIIA.
  
  
  METHODS
  A novel DNA fragment encoding CTX MVIIA was designed using Escherichia coli-preferred codons, and the fragment was cloned into the expression vector pGEX(2T). The fusion protein, CTX MVIIA and glutathione-S-transferase (GST) [GST-CTX MVIIA], was expressed in E. coli and purified by affinity chromatography on a glutathione-agarose column. After digestion with thrombin, the CTX MVIIA fragment was purified on a Sephacryl S-100 HR column and identified by mass spectrometry. The bioactivity of the peptide was evaluated by the hot tail-flick assay, in which the CTX MVIIA was intracerebroventricularly administered into Sprague-Dawley rats and its antinociceptive effect measured.
  
  
  RESULTS
  The analgesic activity of the conotoxin was about 800 times stronger than that of morphine.
  
  
  CONCLUSIONS
  The recombinant CTX MVIIA expressed in E. coli has shown marked analgesic activity, which may have potential in clinical application.
authors.affiliation: Department of Biochemistry and Molecular Biology, Zhejiang University Medical School, 353 Yan-An Road, Hangzhou 310006, People's Republic of China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xia
authors.forename: Yongdui
authors.initials: Y
authors.lastname: Chen
authors.forename: Yongping
authors.initials: Y
authors.lastname: Zhu
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Xu
authors.forename: Jinbiao
authors.initials: J
authors.lastname: Zhan
mesh_terms: D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D004274:DNA, Recombinant / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D013917:Thrombin / Q000378:metabolism; D020960:omega-Conotoxins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000700:Analgesics; D004274:DNA, Recombinant; D011993:Recombinant Fusion Proteins; D020960:omega-Conotoxins; D013917:Thrombin