Tunjung Mahatmanto, Isyatul Azizah, Alex Buchberger, Nicholas Stephanopoulos
In the present study, leaves from 39 phylogenetically distant plant species were sampled and screened for asparaginyl endopeptidase ligase activity using mass spectrometry to test the generality of peptide ligases in plants. A modified version of the sunflower trypsin inhibitor-1 precursor was used as the substrate for reactions with leaf crude extracts and protein fractions. Masses consistent with products of asparaginyl endopeptidase activities that cleave and ligate the substrate into cyclic peptide following the reactions were detected in 8 plants: Nerium oleander and Thevetia peruviana of the family Apocynaceae; Bauhinia variegata, Dermatophyllum secundiflorum, Pithecellobium flexicaule, and Prosopis chilensis of the family Fabaceae; Morus alba of the family Moraceae; and Citrus aurantium of the family Rutaceae. This screening result represents a 20% hit rate for finding asparaginyl endopeptidase ligase activity from the arbitrary plants sampled. Analysis following a 2-h reaction of the substrate with the crude extract of D. secundiflorum leaves showed that the yield of cyclic peptide remained stable around 0.5 ± 0.1% of the substrate over the course of the reaction. © 2019, King Abdulaziz City for Science and Technology.
Department of Agricultural Product Technology, Faculty of Agricultural Technology, Universitas Brawijaya, Malang, East Java, Indonesia; Center for Molecular Design and Biomimetics at the Biodesign Institute, Arizona State University, Tempe, AZ, United States; Department of Biology, Faculty of Mathematics and Life Sciences, Universitas Brawijaya, Malang, East Java, Indonesia; School of Molecular Sciences, Arizona State University, Tempe, AZ, United States; Jurusan Teknologi Hasil Pertanian, Fakultas Teknologi Pertanian, Universitas Brawijaya, Jl. Veteran, Malang, 65145, Jawa Timur, Indonesia
