STRUCTURE AND PROPERTIES OF SURFACTANT PROTEIN-B

Surfactant protein B is a small homodimeric protein that is found tigh tly associated with surfactant lipids in the alveolar space. In this r eview, we discuss the actions of SP-B on phospholipid membranes using information predominantly obtained from model membrane systems. We try to correlate these model actions with current concepts of SP-B struct ure and proposed biological functions. These functions may include cri tical roles in the intracellular assembly of surfactant through a role in lamellar body organogenesis, the structural rearrangement of secre ted surfactant lipids into tubular myelin, and the subsequent rapid in sertion of secreted surfactant phospholipids into the surface film its elf. The relevance of SP-B to human biology is emphasized by the fatal respiratory distress that is associated with a genetic deficiency of SP-B and the important role of SP-B in certain exogenous surfactant fo rmulations in wide clinical use. (C) 1998 Elsevier Science B.V. All ri ghts reserved.