Preparation and characterization of a biologically active spin-labeled sea anemone toxin.
J Protein Chem
; 15(5): 427-34, 1996 Jul.
Article
em En
| MEDLINE
| ID: mdl-8895087
ABSTRACT
A derivative of the polypeptide cardiostimulant anthopleurin-B(AP-B) labeled with the spin label 1-oxyl 2,2,6,6-tetramethyl-4-piperidinyloxycarbonyl azide has been prepared and characterized. The product was found by mass spectrometry to be labeled at a single site, which amino acid sequencing showed to be the N-terminus. It also retained positive inotropic activity when assayed on isolated guinea pig atria. The spin-labeled (SL) product was found to exist in two distinct conformations by reversed-phase HPLC and in at least two conformations by electron spin resonance spectroscopy (ESR) over the pH range 2-9. The ESR data also show evidence for multimetric states of SL-AP-B over the pH range 2-9, with maximum aggregation at pH 4.5-5, and a slow disaggregation when the pH is adjusted to 8-9. The presence of multiple conformers of SL-AP-B and its tendency to aggregate render it unsuitable for high-resolution NMR structural studies of the isolated ligand, but the retention of activity may make it useful for studies of the sodium-channel-bound form of the molecule.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Anêmonas-do-Mar
/
Toxinas Marinhas
Limite:
Animals
Idioma:
En
Ano de publicação:
1996
Tipo de documento:
Article