Deuterium NMR Studies of Component Interactions in Lung Surfactant Materials
Lung inflation depends on a lipid layer that reduces surface tension at the air-water interface. Surfactant precursor material contains saturated lipid (DPPC), anionic unsaturated lipid, hydrophobic proteins (SP-B and SP-C) and hydrophilic proteins (SP-A and SP-D, likely for host defense). As lung volume cycles, material must be transferred from bilayer reservoirs to the interface. We study protein-lipid interactions, within surfactant material, that can promote this reorganization. This work also contributes to development of treatments for surfactant abnormalities and has been pursued collaboratively with K. Keough, V. Booth, and K. Nag, all from the Department of Biochemistry at Memorial, and J. Pérez-Gil from Complutense, Madrid. We have looked at how SP-A interacts with the bilayer surface and have compared how specific surfactant proteins interact with different lipid components in model surfactant material. We recently found that one SP-B segment reduces the tendency for model surfactant lipids to phase separate. This adds to our understanding of surfactant layer stability under compression as occurs on exhalation. SP-C, a trans-bilayer protein with two acyl chains near its N-terminal end, also helps to maintain the surfactant layer. With the Pérez-Gil group, we showed that SP-C acyl chains are less ordered than surrounding lipid chains, suggesting a role for SP-C in promotion of bilayer fusion, a prerequisite for transfer of lipid from bilayer reservoirs to the interface. Our recent study of bilayer perturbation by a C-terminal segment of SP-B used mechanical orientation methods that will be applicable to other protein-lipid work.
30 Nov -0001
Strategic Research Theme
Information and Communication Technology
Well-being, Health and Biomedical Discovery