1T9E
NMR solution structure of a disulfide analogue of the cyclic sunflower trypsin inhibitor SFTI-1
Summary for 1T9E
| Entry DOI | 10.2210/pdb1t9e/pdb |
| Related | 1JBL 1JBN 1O8Y 1O8Z 1SFI |
| Descriptor | Trypsin inhibitor 1 (1 entity in total) |
| Functional Keywords | sunflower trypsin inhibitor, disulfide mutant, hydrolase-hydrolase inhibitor complex, hydrolase/hydrolase inhibitor |
| Biological source | Helianthus annuus (Common sunflower) |
| Total number of polymer chains | 1 |
| Total formula weight | 1499.75 |
| Authors | Korsinczky, M.L.J.,Clark, R.J.,Craik, D.J. (deposition date: 2004-05-16, release date: 2005-05-03, Last modification date: 2025-03-26) |
| Primary citation | Korsinczky, M.L.J.,Clark, R.J.,Craik, D.J. Disulfide bond mutagenesis and the structure and function of the head-to-tail macrocyclic trypsin inhibitor SFTI-1 Biochemistry, 44:1145-1153, 2005 Cited by PubMed Abstract: SFTI-1 is a novel 14 amino acid peptide comprised of a circular backbone constrained by three proline residues, a hydrogen-bond network, and a single disulfide bond. It is the smallest and most potent known Bowman-Birk trypsin inhibitor and the only one with a cyclic peptidic backbone. The solution structure of [ABA(3,11)]SFTI-1, a disulfide-deficient analogue of SFTI-1, has been determined by (1)H NMR spectroscopy. The lowest energy structures of native SFTI-1 and [ABA(3,11)]SFTI-1 are similar and superimpose with a root-mean-square deviation over the backbone and heavy atoms of 0.26 +/- 0.09 and 1.10 +/- 0.22 A, respectively. The disulfide bridge in SFTI-1 was found to be a minor determinant for the overall structure, but its removal resulted in a slightly weakened hydrogen-bonding network. To further investigate the role of the disulfide bridge, NMR chemical shifts for the backbone H(alpha) protons of two disulfide-deficient linear analogues of SFTI-1, [ABA(3,11)]SFTI-1[6,5] and [ABA(3,11)]SFTI-1[1,14] were measured. These correspond to analogues of the cleavage product of SFTI-1 and a putative biosynthetic precursor, respectively. In contrast with the cyclic peptide, it was found that the disulfide bridge is essential for maintaining the structure of these open-chain analogues. Overall, the hydrogen-bond network appears to be a crucial determinant of the structure of SFTI-1 analogues. PubMed: 15667208DOI: 10.1021/bi048297r PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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