1pt4
From Proteopedia
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'''Solution structure of the Moebius cyclotide kalata B2''' | '''Solution structure of the Moebius cyclotide kalata B2''' | ||
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[[Category: Jennings, C V.]] | [[Category: Jennings, C V.]] | ||
[[Category: Rosengren, K J.]] | [[Category: Rosengren, K J.]] | ||
| - | [[Category: | + | [[Category: Cck]] |
| - | [[Category: | + | [[Category: Circular protein]] |
| - | [[Category: | + | [[Category: Cyclic cystine knot]] |
| - | [[Category: | + | [[Category: Cyclotide]] |
| - | [[Category: | + | [[Category: Kalata]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 05:27:33 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 02:27, 3 May 2008
Solution structure of the Moebius cyclotide kalata B2
Overview
A large number of macrocyclic miniproteins with diverse biological activities have been isolated from the Rubiaceae, Violaceae, and Cucurbitaceae plant families in recent years. Here we report the three-dimensional structure determined using (1)H NMR spectroscopy and demonstrate potent insecticidal activity for one of these peptides, kalata B2. This peptide is one of the major components of an extract from the leaves of the plant Oldenlandia affinis. The structure consists of a distorted triple-stranded beta-sheet and a cystine knot arrangement of the disulfide bonds and is similar to those described for other members of the cyclotide family. The unique cyclic and knotted nature of these molecules makes them a fascinating example of topologically complex proteins. Examination of the sequences reveals that they can be separated into two subfamilies, one of which contains a larger number of positively charged residues and has a bracelet-like circularization of the backbone. The second subfamily contains a backbone twist due to a cis-peptidyl-proline bond and may conceptually be regarded as a molecular Mobius strip. Kalata B2 is the second putative member of the Mobius cyclotide family to be structurally characterized and has a cis-peptidyl-proline bond, thus validating the suggested name for this subfamily of cyclotides. The observation that kalata B2 inhibits the growth and development of Helicoverpa armigera larvae suggests a role for the cyclotides in plant defense. A comparison of the sequences and structures of kalata B1 and B2 provides insight into the biological activity of these peptides.
About this Structure
1PT4 is a Single protein structure of sequence from Oldenlandia affinis. Full crystallographic information is available from OCA.
Reference
Isolation, solution structure, and insecticidal activity of kalata B2, a circular protein with a twist: do Mobius strips exist in nature?, Jennings CV, Rosengren KJ, Daly NL, Plan M, Stevens J, Scanlon MJ, Waine C, Norman DG, Anderson MA, Craik DJ, Biochemistry. 2005 Jan 25;44(3):851-60. PMID:15654741 Page seeded by OCA on Sat May 3 05:27:33 2008
