5a24 Citations

Enzymatic and structural characterization of the major endopeptidase in the Venus flytrap digestion fluid.


Carnivorous plants primarily use aspartic proteases during digestion of captured prey. In contrast, the major endopeptidases in the digestive fluid of the Venus flytrap (Dionaea muscipula) are cysteine proteases (dionain-1 to -4). Here, we present the crystal structure of mature dionain-1 in covalent complex with inhibitor E-64 at 1.5 A resolution. The enzyme exhibits an overall protein fold reminiscent of other plant cysteine proteases. The inactive glycosylated pro-form undergoes autoprocessing and self-activation, optimally at the physiologically relevant pH value of 3.6, at which the protective effect of the pro-domain is lost. The mature enzyme was able to efficiently degrade a Drosophila fly protein extract at pH 4 showing high activity against the abundant Lys- and Arg-rich protein, myosin. The substrate specificity of dionain-1 was largely similar to that of papain with preference for hydrophobic and aliphatic residues in subsite S2 and for positively charged residues in S1. A tentative structure of the pro-domain was obtained by homology modeling and suggested that a pro-peptide Lys residue intrudes the S2 pocket which is more spacious than in papain. This study provides the first analysis of a cysteine protease from the digestive fluid of a carnivorous plant and confirms the close relationship between carnivorous action and plant defense mechanisms.

Articles citing this publication (6)

  1. Long-read sequencing uncovers the adaptive topography of a carnivorous plant genome. Lan T, Renner T, Ibarra-Laclette E, Farr KM, Chang TH, Cervantes-Pérez SA, Zheng C, Sankoff D, Tang H, Purbojati RW, Putra A, Drautz-Moses DI, Schuster SC, Herrera-Estrella L, Albert VA. Proc. Natl. Acad. Sci. U.S.A. 114 E4435-E4441 (2017)
  2. The role of electrical and jasmonate signalling in the recognition of captured prey in the carnivorous sundew plant Drosera capensis. Krausko M, Perutka Z, Šebela M, Šamajová O, Šamaj J, Novák O, Pavlovič A. New Phytol. 213 1818-1835 (2017)
  3. Novel proteases from the genome of the carnivorous plant Drosera capensis: Structural prediction and comparative analysis. Butts CT, Bierma JC, Martin RW. Proteins 84 1517-1533 (2016)
  4. Sequence comparison, molecular modeling, and network analysis predict structural diversity in cysteine proteases from the Cape sundew, Drosera capensis. Butts CT, Zhang X, Kelly JE, Roskamp KW, Unhelkar MH, Freites JA, Tahir S, Martin RW. Comput Struct Biotechnol J 14 271-282 (2016)
  5. Structure prediction and network analysis of chitinases from the Cape sundew, Drosera capensis. Unhelkar MH, Duong VT, Enendu KN, Kelly JE, Tahir S, Butts CT, Martin RW. Biochim Biophys Acta Gen Subj 1861 636-643 (2017)
  6. Discovery of digestive enzymes in carnivorous plants with focus on proteases. Ravee R, Mohd Salleh F', Goh HH. PeerJ 6 e4914 (2018)