Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin
Heat-stable enterotoxin (ST<sub>a</sub>) produced by enterotoxigenic <i>E. coli</i> causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST<sub>a</sub> contains three intra-molecular disulfide bonds (C1–C4, C2–C5, and C3–C6 c...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-10-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/25/20/4798 |
| _version_ | 1797550354651414528 |
|---|---|
| author | Shigeru Shimamoto Mayu Fukutsuji Toi Osumi Masaya Goto Hiroshi Toyoda Yuji Hidaka |
| author_facet | Shigeru Shimamoto Mayu Fukutsuji Toi Osumi Masaya Goto Hiroshi Toyoda Yuji Hidaka |
| author_sort | Shigeru Shimamoto |
| collection | DOAJ |
| description | Heat-stable enterotoxin (ST<sub>a</sub>) produced by enterotoxigenic <i>E. coli</i> causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST<sub>a</sub> contains three intra-molecular disulfide bonds (C1–C4, C2–C5, and C3–C6 connectivity). The chemical synthesis of ST<sub>a</sub> provided not only the native type of ST<sub>a</sub> but also a topological isomer that had the native disulfide pairings. Interestingly, the activity of the topological isomer was approximately 1/10–1/2 that of the native ST<sub>a</sub>. To further investigate the bioactive conformation of this molecule and the regulation of disulfide-coupled folding during its chemical syntheses, we examined the folding mechanism of ST<sub>a</sub> that occurs during its chemical synthesis. The folding intermediate of ST<sub>a</sub> with two disulfide bonds (C1–C4 and C3–C6) and two Cys(Acm) residues, the precursor peptide, was treated with iodine to produce a third disulfide bond under several conditions. The topological isomer was predominantly produced under all conditions tested, along with trace amounts of the native type of ST<sub>a</sub>. In addition, NMR measurements indicated that the topological isomer has a left-handed spiral structure similar to that of the precursor peptide, while the native type of ST<sub>a</sub> had a right-handed spiral structure. These results indicate that the order of the regioselective formation of disulfide bonds is important for the regulation of the final conformation of disulfide-rich peptides in chemical synthesis. |
| first_indexed | 2024-03-10T15:28:02Z |
| format | Article |
| id | doaj.art-e6d2ab970b794bdbbd6412919c136d0a |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T15:28:02Z |
| publishDate | 2020-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e6d2ab970b794bdbbd6412919c136d0a2023-11-20T17:53:09ZengMDPI AGMolecules1420-30492020-10-012520479810.3390/molecules25204798Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable EnterotoxinShigeru Shimamoto0Mayu Fukutsuji1Toi Osumi2Masaya Goto3Hiroshi Toyoda4Yuji Hidaka5Faculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanFaculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanFaculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanFaculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanFaculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanFaculty of Science and Engineering, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, JapanHeat-stable enterotoxin (ST<sub>a</sub>) produced by enterotoxigenic <i>E. coli</i> causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST<sub>a</sub> contains three intra-molecular disulfide bonds (C1–C4, C2–C5, and C3–C6 connectivity). The chemical synthesis of ST<sub>a</sub> provided not only the native type of ST<sub>a</sub> but also a topological isomer that had the native disulfide pairings. Interestingly, the activity of the topological isomer was approximately 1/10–1/2 that of the native ST<sub>a</sub>. To further investigate the bioactive conformation of this molecule and the regulation of disulfide-coupled folding during its chemical syntheses, we examined the folding mechanism of ST<sub>a</sub> that occurs during its chemical synthesis. The folding intermediate of ST<sub>a</sub> with two disulfide bonds (C1–C4 and C3–C6) and two Cys(Acm) residues, the precursor peptide, was treated with iodine to produce a third disulfide bond under several conditions. The topological isomer was predominantly produced under all conditions tested, along with trace amounts of the native type of ST<sub>a</sub>. In addition, NMR measurements indicated that the topological isomer has a left-handed spiral structure similar to that of the precursor peptide, while the native type of ST<sub>a</sub> had a right-handed spiral structure. These results indicate that the order of the regioselective formation of disulfide bonds is important for the regulation of the final conformation of disulfide-rich peptides in chemical synthesis.https://www.mdpi.com/1420-3049/25/20/4798disulfideenterotoxinfoldingguanylyl cyclasetopological |
| spellingShingle | Shigeru Shimamoto Mayu Fukutsuji Toi Osumi Masaya Goto Hiroshi Toyoda Yuji Hidaka Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin Molecules disulfide enterotoxin folding guanylyl cyclase topological |
| title | Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin |
| title_full | Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin |
| title_fullStr | Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin |
| title_full_unstemmed | Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin |
| title_short | Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin |
| title_sort | topological regulation of the bioactive conformation of a disulfide rich peptide heat stable enterotoxin |
| topic | disulfide enterotoxin folding guanylyl cyclase topological |
| url | https://www.mdpi.com/1420-3049/25/20/4798 |
| work_keys_str_mv | AT shigerushimamoto topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin AT mayufukutsuji topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin AT toiosumi topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin AT masayagoto topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin AT hiroshitoyoda topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin AT yujihidaka topologicalregulationofthebioactiveconformationofadisulfiderichpeptideheatstableenterotoxin |