Discovery of highly efficient recombinant peptide ligases

• Main Author: Mok, Jia Le
• Other Authors: James P Tam
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Science::Biological sciences
• Online Access: https://hdl.handle.net/10356/140916
• Institution: Nanyang Technological University

A unique group of ligases called Asparaginyl endopeptidases (AEPs) can Asn- or Asp- specific hydrolysis and/or transpeptidation in water. With the recognition motif of Asx-Xaa-Yaa, AEPs catalyse ligation with a broad range of peptides. Yet, these AEPs are interchangeable between protease, ligase or as a dual-functional enzyme with pH and specific substrate sequence. Enzyme or substrate engineering are known approaches to confer optimal ligase activity in AEP and control AEP elusive nature of pH and substrate dependency. Our laboratory has recently discovered an AEP from Momordica cochinchinensis (Gac) named McAEP 1. Here, we report the characterization of McAEP 1 and the influence of substrates on the activity profile. Through sequence alignment of known AEPs with predominant ligase activity coupled with P1 variant model peptide library in vitro activity test, we found that McAEP 1 can catalyse substrates with P1-Asx. McAEP 1 in vitro activity test with P2 model peptide variants presents a unique profile of activities and it suggests that with a combination of substrate engineering, McAEP1 is a unique bifunctional AEP in nature.