One enzyme with two functions : how to train proteases to perform ligation

Cyclotides, a class of plant-derived cysteine-rich cyclic proteins, are an attractive framework for drug design. Asparaginyl endopeptidases (AEPs) are enzymes that are associated with proteolysis, but there is a class of AEPs that catalyze the backbone cyclization of cyclotide precursors. Here, we r...

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Bibliographic Details
Main Author: Kay, Senica Zi Ning
Other Authors: James P Tam
Format: Final Year Project
Language:English
Published: Nanyang Technological University 2020
Subjects:
Online Access:https://hdl.handle.net/10356/143326
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Institution: Nanyang Technological University
Language: English
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Summary:Cyclotides, a class of plant-derived cysteine-rich cyclic proteins, are an attractive framework for drug design. Asparaginyl endopeptidases (AEPs) are enzymes that are associated with proteolysis, but there is a class of AEPs that catalyze the backbone cyclization of cyclotide precursors. Here, we report on how to train the bifunctional AEP McPAL-1 to carry out ligation by changing influencing factors. We found that AEPs are substrate specific and the P2” residue affects the directionality of McPAL-1’s activity. The P1 residue and pH is also a determinant of AEP activity. Additionally, we note that the C-terminus of substrates play an important role in catalyzing enzyme reactions. We also made the discovery that previously thought to be ligase-type and protease-type AEPs, are actually all bifunctional in activity.