Sequence specific super(1)H-NMR assignments and secondary structure of a carboxy-terminal functional fragment of apolipoprotein CII

The structural properties of a synthetic fragment of human apolipoprotein CII (apoCII) has been studied by circular dichroism and proton nuclear magnetic resonance. The fragment corresponds to the carboxy-terminal 30 amino acid residues and retains the ability of apoCII to activate lipoprotein lipase. Like native apoCII, the fragment has a tendency to self-associate in pure aqueous solution. Addition of 1,1,1,3,3,3-hexafluoro-2-isopropanol to aqueous solvent dissolves the aggregates and leads to an increase in the alpha -helical content of the peptide, probably by stabilizing transient helical structures. The resonances in the super(1)H-NMR spectrum of the fragment in 35% (CF sub(3)) sub(2)CHOH were assigned through standard procedures from nuclear Overhauser enhancement spectroscopy, correlated spectroscopy, and total correlated spectroscopy experiments.