Molecular basis for the production of cyclic peptides by plant asparaginyl endopeptidases
journal contributionposted on 11.02.2021, 23:49 by MA Jackson, EK Gilding, Thomas Shafee, Karen Harris, Q Kaas, Simon Poon, K Yap, H Jia, Rosemary Guarino, LY Chan, T Durek, Marilyn Anderson, DJ Craik
© 2018 The Author(s). Asparaginyl endopeptidases (AEPs) are proteases that have crucial roles in plant defense and seed storage protein maturation. Select plant AEPs, however, do not function as proteases but as transpeptidases (ligases) catalyzing the intra-molecular ligation of peptide termini, which leads to peptide cyclization. These ligase-type AEPs have potential biotechnological applications ranging from in vitro peptide engineering to plant molecular farming, but the structural features enabling these enzymes to catalyze peptide ligation/cyclization rather than proteolysis are currently unknown. Here, we compare the sequences, structures, and functions of diverse plant AEPs by combining molecular modeling, sequence space analysis, and functional testing in planta. We find that changes within the substrate-binding pocket and an adjacent loop, here named the "marker of ligase activity", together play a key role for AEP ligase efficiency. Identification of these structural determinants may facilitate the discovery of more ligase-type AEPs and the engineering of AEPs with tailored catalytic properties.
The pEAQ vectors were kindly provided by Prof. George Lomonossoff at the John Innes Centre and Plant Bioscience Ltd. We acknowledge funding from the Australian Research Council (ARC Laureate Fellowship (FL150100146) to D.J.C. and ARC grant DP150100443 to D.J.C., E.K.G., and T.D.). This research was also supported by the 2015 Ramaciotti Biomedical Research Award to D.J.C. and M.A.A. and by Hexima Ltd.
Australian Research Council (ARC) | FL150100146
Australian Research Council (ARC) | DP150100443
Ramaciotti Biomedical Research Award
Pagination12p. (p. 1-12)
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Science & TechnologyMultidisciplinary SciencesScience & Technology - Other TopicsKNOTTED PROTEINSHOST-DEFENSECYSTINE KNOTCELL-DEATHKALATA B1CYCLOTIDESBIOSYNTHESISLEGUMAINFAMILYCYCLIZATIONPlantsPlants, Genetically ModifiedPeptides, CyclicCysteine EndopeptidasesPlant ProteinsRNA, PlantSequence Analysis, RNAModels, Molecular