Procerain B, a cysteine protease from Calotropis procera, requires N-terminus pro-region for activity: cDNA cloning and expression with pro-sequence

Protein Expr Purif. 2014 Nov;103:16-22. doi: 10.1016/j.pep.2014.08.003. Epub 2014 Aug 27.


We have previously reported isolation and characterization of a novel plant cysteine protease, Procerain B, from the latex of Calotropis procera. Our initial attempts for active recombinant Procerain B in Escherichiacoli expression system was not successful. The reason for inactive enzyme production was attributed to the absence of 5' pro-region in the Procerain B cDNA that may be involved in proper folding and production of mature active protein. The current manuscript reports the cloning of full length Procerain B for the production of the active protein. The complete cDNA sequence of Procerain B with pro-region sequence was obtained by using RNA ligase mediated rapid amplification of 5' cDNA ends (RLM-RACE). The N-terminus pro-sequence region consists of 127 amino acids and characterized as the member of inhibitory I29 family. Further the three dimensional structure of full length Procerain B was modelled by homology modelling using X-ray crystal structure of procaricain (PDB ID: 1PCI). N-terminus pro-sequence of full length Procerain B runs along the active site cleft. Full length Procerain B was expressed in prokaryotic system and activated in vitro at pH 4.0. This is the first study reporting the production of active recombinant cysteine protease from C.procera.

Keywords: Full length cDNA; I29 inhibitory propeptide; In vitro activation; Protease; RLM-RACE; Recombinant Procerain B.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Calotropis / enzymology*
  • Cloning, Molecular
  • Crystallography, X-Ray
  • Cysteine Endopeptidases / biosynthesis
  • Cysteine Endopeptidases / chemistry*
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / isolation & purification
  • Cysteine Proteases / biosynthesis
  • Cysteine Proteases / chemistry*
  • Cysteine Proteases / genetics
  • Cysteine Proteases / isolation & purification
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • High-Throughput Nucleotide Sequencing
  • Molecular Sequence Data
  • Protein Conformation


  • DNA, Complementary
  • Cysteine Proteases
  • Cysteine Endopeptidases
  • procerain

Associated data

  • GENBANK/KJ544247
  • PDB/PM0079537