Abstract
Anthopleurin-A (AP-A) is a member of a family of sea anemone-derived polypeptides that interact with sodium channels in a voltage-dependent manner, producing a positive inotropic effect on the mammalian heart. There has been considerable interest in this molecule as a lead compound for the development of novel therapeutic agents. Earlier attempts to define the 3-dimensional structure of AP-A were complicated by the fact that it was found to exist in 2 conformations in solution. Using 1H- and 13C-NMR spectroscopy, we have now shown that this conformational heterogeneity arises from cis-trans isomerization about the Gly 40-Pro 41 peptide bond and that in the major form of the protein this peptide bond adopts a cis conformation. Furthermore, the increased sensitivity afforded by higher-field NMR has allowed identification of additional minor conformations of AP-A, the origin of which is presently unknown. We believe there will be many more examples of the detection by high-field NMR of previously unobserved minor conformations of proteins in solution.
Full Text
The Full Text of this article is available as a PDF (335.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Blair R. W., Peterson D. F., Bishop V. S. The effects of anthopleurin-A on cardiac dynamics in conscious dogs. J Pharmacol Exp Ther. 1978 Nov;207(2):271–276. [PubMed] [Google Scholar]
- Evans P. A., Dobson C. M., Kautz R. A., Hatfull G., Fox R. O. Proline isomerism in staphylococcal nuclease characterized by NMR and site-directed mutagenesis. Nature. 1987 Sep 17;329(6136):266–268. doi: 10.1038/329266a0. [DOI] [PubMed] [Google Scholar]
- Gooley P. R., Blunt J. W., Beress L., Norton R. S. Effects of pH and temperature on cardioactive polypeptides from sea anemones: a 1H-NMR study. Biopolymers. 1988 Jul;27(7):1143–1157. doi: 10.1002/bip.360270708. [DOI] [PubMed] [Google Scholar]
- Gooley P. R., Blunt J. W., Norton R. S. Conformational heterogeneity in polypeptide cardiac stimulants from sea anemones. FEBS Lett. 1984 Aug 20;174(1):15–19. doi: 10.1016/0014-5793(84)81068-6. [DOI] [PubMed] [Google Scholar]
- Gooley P. R., Norton R. S. Specific assignment of resonances in the 1H nuclear magnetic resonance spectrum of the polypeptide cardiac stimulant anthopleurin-A. Eur J Biochem. 1985 Dec 16;153(3):529–539. doi: 10.1111/j.1432-1033.1985.tb09334.x. [DOI] [PubMed] [Google Scholar]
- Mabbutt B. C., Norton R. S. Sequential 1H-NMR assignments and secondary structure of the sea anemone polypeptide anthopleurin-A. Eur J Biochem. 1990 Feb 14;187(3):555–563. doi: 10.1111/j.1432-1033.1990.tb15337.x. [DOI] [PubMed] [Google Scholar]
- Norton R. S. Structure and structure-function relationships of sea anemone proteins that interact with the sodium channel. Toxicon. 1991;29(9):1051–1084. doi: 10.1016/0041-0101(91)90205-6. [DOI] [PubMed] [Google Scholar]
- Otting G., Liepinsh E., Wüthrich K. Disulfide bond isomerization in BPTI and BPTI(G36S): an NMR study of correlated mobility in proteins. Biochemistry. 1993 Apr 13;32(14):3571–3582. doi: 10.1021/bi00065a008. [DOI] [PubMed] [Google Scholar]
- Santoro J., González C., Bruix M., Neira J. L., Nieto J. L., Herranz J., Rico M. High-resolution three-dimensional structure of ribonuclease A in solution by nuclear magnetic resonance spectroscopy. J Mol Biol. 1993 Feb 5;229(3):722–734. doi: 10.1006/jmbi.1993.1075. [DOI] [PubMed] [Google Scholar]
- Scriabine A., Van Arman C. G., Morgan G., Morris A. A., Bennett C. D., Bohidar N. R. Cardiotonic effects of anthopleurin-A, a polypeptide from a sea anemone. J Cardiovasc Pharmacol. 1979 Sep-Oct;1(5):571–583. doi: 10.1097/00005344-197909000-00009. [DOI] [PubMed] [Google Scholar]
- Wagner G., Zuiderweg E. R. Two-dimensional double quantum 1H NMR spectroscopy of proteins. Biochem Biophys Res Commun. 1983 Jun 29;113(3):854–860. doi: 10.1016/0006-291x(83)91077-x. [DOI] [PubMed] [Google Scholar]