CHARACTER OF STORED MOLECULES IN CHROMAFFIN GRANULES OF ADRENAL-MEDULLA - NUCLEAR MAGNETIC-RESONANCE STUDY

DANIELS, AJ; WILLIAMS, RJP; WRIGHT, PE

CHARACTER OF STORED MOLECULES IN CHROMAFFIN GRANULES OF ADRENAL-MEDULLA - NUCLEAR MAGNETIC-RESONANCE STUDY

Date

1978

Authors

DANIELS, AJ

WILLIAMS, RJP

WRIGHT, PE

Abstract

The organization of the internal contents of bovine adrenal chromaffin granules were studied using NMR spectroscopy. The method permits an examination of the interactions between ATP metal ions, adrenaline [epinephrine] and the chromogranin proteins. Particular advantage accrues when the naturally occurring cations Mg and Ca are replaced by Mn cations, since Mn2+ is an effective perturbing probe. Protein spectrum in the vesicles was compared with that of the isolated proteins. There was a loose network of interactions between the various components. The major part of the network was the interaction of the chromogranin protein, shown to have approximately a random coil conformation, with the ATP and the adrenaline. The organized loose structure appeared to lower osmotic pressure without hindering rapid release of the vesicle contents breaking the membrane.