1N1U
NMR structure of [Ala1,15]kalata B1
Summary for 1N1U
| Entry DOI | 10.2210/pdb1n1u/pdb |
| NMR Information | BMRB: 5609 |
| Descriptor | kalata B1 (1 entity in total) |
| Functional Keywords | cystine knot, triple stranded beta sheet, cyclic peptide, antibiotic |
| Total number of polymer chains | 1 |
| Total formula weight | 2853.22 |
| Authors | Daly, N.L.,Clark, R.J.,Craik, D.J. (deposition date: 2002-10-20, release date: 2003-02-25, Last modification date: 2024-10-16) |
| Primary citation | Daly, N.L.,Clark, R.J.,Craik, D.J. Disulfide Folding Pathways of Cystine Knot Proteins. TYING THE KNOT WITHIN THE CIRCULAR BACKBONE OF THE CYCLOTIDES J.Biol.Chem., 278:6314-6322, 2003 Cited by PubMed Abstract: The plant cyclotides are a fascinating family of circular proteins that contain a cyclic cystine knot motif. The knotted topology and cyclic nature of the cyclotides pose interesting questions about folding mechanisms and how the knotted arrangement of disulfide bonds is formed. In the current study we have examined the oxidative refolding and reductive unfolding of the prototypic cyclotide, kalata B1. A stable two-disulfide intermediate accumulated during oxidative refolding but not in reductive unfolding. Mass spectrometry and NMR spectroscopy were used to show that the intermediate contained a native-like structure with two native disulfide bonds topologically similar to the intermediate isolated for the related cystine knot protein EETI-II (Le-Nguyen, D., Heitz, A., Chiche, L., El Hajji, M., and Castro B. (1993) Protein Sci. 2, 165-174). However, the folding intermediate observed for kalata B1 is not the immediate precursor of the three-disulfide native peptide and does not accumulate in the reductive unfolding process, in contrast to the intermediate observed for EETI-II. These alternative pathways of linear and cyclic cystine knot proteins appear to be related to the constraints imposed by the cyclic backbone of kalata B1 and the different ring size of the cystine knot. The three-dimensional structure of a synthetic version of the two-disulfide intermediate of kalata B1 in which Ala residues replace the reduced Cys residues provides a structural insight into why the two-disulfide intermediate is a kinetic trap on the folding pathway. PubMed: 12482862DOI: 10.1074/jbc.M210492200 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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