Interactions of bile salt micelles and colipase studied through intermolecular nOes

Colipase is a small protein (10 kDa), which acts as a protein cofactor for the pancreatic lipase, Various models of the activated ternary complex; (li pase-colipase-bile salt micelles) have been proposed using detergent micell es, but no structural information has been established with bile salt micel les. We hare investigated the organization of sodium taurodeoxycholate (NaT DC) micelles and their interactions with pig and horse colipases by homonuc lear nuclear magnetic resonance (NMR) spectroscopy. The NR;IR data supply e vidence that the folding of horse colipase is similar to that already descr ibed for pig colipase, Intermolecular nuclear Overhauser effects have shown that two conserved aromatic residues interact with NaTDC micelles, (C) 200 0 Federation of European Biochemical Societies, Published by Elsevier Scien ce B.V. All rights reserved.