1apf
From Proteopedia
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'''ANTHOPLEURIN-B, NMR, 20 STRUCTURES''' | '''ANTHOPLEURIN-B, NMR, 20 STRUCTURES''' | ||
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[[Category: Pallaghy, P K.]] | [[Category: Pallaghy, P K.]] | ||
[[Category: Scanlon, M J.]] | [[Category: Scanlon, M J.]] | ||
| - | [[Category: | + | [[Category: Cardiac stimulant]] |
| - | [[Category: | + | [[Category: Sea anemone]] |
| - | [[Category: | + | [[Category: Toxin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 10:33:03 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 07:33, 2 May 2008
ANTHOPLEURIN-B, NMR, 20 STRUCTURES
Overview
BACKGROUND: The polypeptide anthopleurin-B (AP-B) is one of a number of related toxins produced by sea anemones. AP-B delays inactivation of the voltage-gated sodium channel of excitable tissue. In the mammalian heart, this effect is manifest as an increase in the force of contraction. As a result, there is interest in exploiting the anthopleurins as lead compounds in the design of novel cardiac stimulants. Essential to this endeavour is a high-resolution solution structure of the molecule describing the positions of functionally important side chains. RESULTS: AP-B exists in multiple conformations in solution as a result of cis-trans isomerization about the Gly40-Pro41 peptide bond. The solution structure of the major conformer of AP-B has been determined by two-dimensional 1H NMR at pH 4.5 and 25 degrees C. The core structure is a four-stranded, antiparallel beta-sheet (residues 2-4, 20-23, 34-37 and 45-48) and includes several beta-turns (6-9, 25-28, 30-33). Three loops connect the beta-strands, the longest and least well defined being the first loop, extending from residues 8-17. These features are shared by other members of this family of sea anemone toxins. The locations of a number of side chains which are important for the cardiac stimulatory activity of AP-B are well defined in the structures. CONCLUSIONS: We have described the solution structure of AP-B and compared it with that of AP-A, from which it differs by substitutions at seven amino acid positions. It shares an essentially identical fold with AP-A yet is about 10-fold more active. Comparison of the structures, particularly in the region of residues essential for activity, gives a clearer indication of the location and extent of the cardioactive pharmacophore in these polypeptides.
About this Structure
1APF is a Single protein structure of sequence from Anthopleura xanthogrammica. Full crystallographic information is available from OCA.
Reference
Solution structure of the cardiostimulant polypeptide anthopleurin-B and comparison with anthopleurin-A., Monks SA, Pallaghy PK, Scanlon MJ, Norton RS, Structure. 1995 Aug 15;3(8):791-803. PMID:7582896 Page seeded by OCA on Fri May 2 10:33:03 2008
