PULMONARY SURFACTANT-ASSOCIATED POLYPEPTIDE SP-C IN LIPID MICELLES - CD STUDIES OF INTACT SP-C AND NMR SECONDARY STRUCTURE DETERMINATION OFDEPALMITOYL-SP-C(1-17)

The surfactant-associated polypeptide C (SP-C) is a 35-residue lipopol ypeptide which is essential for the function of surfactants used for t herapy of infant respiratory distress. Modeling based on the recently determined nuclear magnetic resonance (NMR) structure of native SP-C i n an organic solvent showed that SP-C could readily insert into fluid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine bilayers, The present pape r describes further physical-chemical studies of intact SP-C and its N -terminal 17-residue polypeptide fragment, depalmitoyl-SP-C(1-17), in the presence of dodecylphosphocholine micelles. The results obtained p rovide a link between the NMR solution structure and the behaviour of SP-C in an ordered lipid environment, and thus present new insights fo r rational design of SP-C analogs for therapeutic purposes.