Broaden the applications of peptidyl asparaginyl ligases
Peptidyl asparaginyl ligases (PALs) are highly active enzymes that catalyse peptide ligation reactions through transpeptidation. To further increase the utility of PALs, I have successfully designed an unnatural analogue of asparagine, Asn(OH), as the P1 substrate of these ligases. Using Asn(OH)-med...
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| Format: | Thesis-Doctor of Philosophy |
| Language: | English |
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Nanyang Technological University
2023
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| Online Access: | https://hdl.handle.net/10356/165731 |
| _version_ | 1826109581567197184 |
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| author | Xia, Yiyin |
| author2 | Liu Chuan Fa |
| author_facet | Liu Chuan Fa Xia, Yiyin |
| author_sort | Xia, Yiyin |
| collection | NTU |
| description | Peptidyl asparaginyl ligases (PALs) are highly active enzymes that catalyse peptide ligation reactions through transpeptidation. To further increase the utility of PALs, I have successfully designed an unnatural analogue of asparagine, Asn(OH), as the P1 substrate of these ligases. Using Asn(OH)-mediated cyclization, a new class of cyclic peptides containing Asn(OH) as the key pharmacophore have been generated, some of which are potent inhibitors of matrix metalloproteinase 2 (MMP2). The Asn(OH) residue can also be easily converted to Asp in a mild oxidation reaction. Furthermore, I have also established a method to overcome the reversibility of PAL-mediated ligation by coupling it to glutaminyl cyclase-catalyzed pyroglutamyl formation which quenches the released leaving group. Using this cascade enzymatic scheme, the PAL-mediated ligation can achieve near-quantitative yields even at an equal molar ratio between two large ligation partners. To conclude, my work has improved the efficiency of PAL-mediated ligation and broadened its application scope. |
| first_indexed | 2024-10-01T02:20:35Z |
| format | Thesis-Doctor of Philosophy |
| id | ntu-10356/165731 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:20:35Z |
| publishDate | 2023 |
| publisher | Nanyang Technological University |
| record_format | dspace |
| spelling | ntu-10356/1657312023-05-02T06:33:01Z Broaden the applications of peptidyl asparaginyl ligases Xia, Yiyin Liu Chuan Fa School of Biological Sciences CFLiu@ntu.edu.sg Science::Biological sciences Peptidyl asparaginyl ligases (PALs) are highly active enzymes that catalyse peptide ligation reactions through transpeptidation. To further increase the utility of PALs, I have successfully designed an unnatural analogue of asparagine, Asn(OH), as the P1 substrate of these ligases. Using Asn(OH)-mediated cyclization, a new class of cyclic peptides containing Asn(OH) as the key pharmacophore have been generated, some of which are potent inhibitors of matrix metalloproteinase 2 (MMP2). The Asn(OH) residue can also be easily converted to Asp in a mild oxidation reaction. Furthermore, I have also established a method to overcome the reversibility of PAL-mediated ligation by coupling it to glutaminyl cyclase-catalyzed pyroglutamyl formation which quenches the released leaving group. Using this cascade enzymatic scheme, the PAL-mediated ligation can achieve near-quantitative yields even at an equal molar ratio between two large ligation partners. To conclude, my work has improved the efficiency of PAL-mediated ligation and broadened its application scope. Doctor of Philosophy 2023-04-10T03:53:05Z 2023-04-10T03:53:05Z 2022 Thesis-Doctor of Philosophy Xia, Y. (2022). Broaden the applications of peptidyl asparaginyl ligases. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/165731 https://hdl.handle.net/10356/165731 10.32657/10356/165731 en M4081930.080.703012-M4081930.080.703012 This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University |
| spellingShingle | Science::Biological sciences Xia, Yiyin Broaden the applications of peptidyl asparaginyl ligases |
| title | Broaden the applications of peptidyl asparaginyl ligases |
| title_full | Broaden the applications of peptidyl asparaginyl ligases |
| title_fullStr | Broaden the applications of peptidyl asparaginyl ligases |
| title_full_unstemmed | Broaden the applications of peptidyl asparaginyl ligases |
| title_short | Broaden the applications of peptidyl asparaginyl ligases |
| title_sort | broaden the applications of peptidyl asparaginyl ligases |
| topic | Science::Biological sciences |
| url | https://hdl.handle.net/10356/165731 |
| work_keys_str_mv | AT xiayiyin broadentheapplicationsofpeptidylasparaginylligases |