The relationships between biophysical activity and the secondary structure of synthetic peptides from the pulmonary surfactant protein SP-B.

Synthetic pulmonary surfactants consisting of a mixture of phospholipids with synthetic peptides based on human and bovine surfactant-associated protein SP-B were prepared. These surfactants were analyzed for their biophysical activities by Wilhemly balance experiments and for their secondary structures by circular dichroism (CD) spectroscopy. Four synthetic peptides (SP-1, SP-2, SP-3, and SP-4) combined with the phospholipid mixture displayed significant surfactant properties. The CD spectra showed that the alpha-helical propensities of the peptides in SDS micelles were related to their surfactant activities. These results suggested that the several truncated peptides originated from SP-B protein, when appropriately recombined with phospholipids, could be used as an effective synthetic surfactant for clinical use.