7D37
Solution structure of Acm2-precursor peptide of Heat-stable enterotoxin produced by Enterotoxigenic Escherichia coli
Summary for 7D37
| Entry DOI | 10.2210/pdb7d37/pdb |
| Descriptor | CYS-CY1-GLU-LEU-CYS-CYS-ASN-PRO-ALA-CY1-THR-GLY-CYS (1 entity in total) |
| Functional Keywords | heat-stable enterotoxin, topological isomer, sth, sth(6-18), toxin |
| Biological source | Escherichia coli |
| Total number of polymer chains | 1 |
| Total formula weight | 1461.75 |
| Authors | |
| Primary citation | Shimamoto, S.,Fukutsuji, M.,Osumi, T.,Goto, M.,Toyoda, H.,Hidaka, Y. Topological Regulation of the Bioactive Conformation of a Disulfide-Rich Peptide, Heat-Stable Enterotoxin. Molecules, 25:-, 2020 Cited by PubMed Abstract: Heat-stable enterotoxin (ST) produced by enterotoxigenic causes acute diarrhea and also can be used as a specific probe for colorectal cancer cells. ST contains three intra-molecular disulfide bonds (C1-C4, C2-C5, and C3-C6 connectivity). The chemical synthesis of ST provided not only the native type of ST 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. 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 that occurs during its chemical synthesis. The folding intermediate of ST 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. 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 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. PubMed: 33096591DOI: 10.3390/molecules25204798 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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