1t9e | pdb_00001t9e

NMR solution structure of a disulfide analogue of the cyclic sunflower trypsin inhibitor SFTI-1

spinqualitylabelsall models 1t9e, 20 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1t9e is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: ABA Related: 1sfi, 1jbl, 1jbn, 1o8y, 1o8z Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SFTI1_HELAN] Inhibits trypsin, cathepsin G, elastase, chymotrypsin and thrombin. Does not inhibit factor Xa. Publication Abstract from PubMed 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. Disulfide bond mutagenesis and the structure and function of the head-to-tail macrocyclic trypsin inhibitor SFTI-1.,Korsinczky ML, Clark RJ, Craik DJ Biochemistry. 2005 Feb 1;44(4):1145-53. PMID:15667208 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Trypsin inhibitor 3D structures

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