Antibodies against synthetic amphipathic helical sequences of surfactant protein SP‐B detect a conformational change in the native protein

Synthetic peptides based on the native human sequence of surfactant protein B have been used to generate polyclonal monospecific antibodies against specific segments of the native SP-B protein. Circular dichroism analysis of the synthetic peptides shows they have a dominant helical content in structure promoting environments and tensiometric measurements indicate these peptides lower surface tension at air-water interfaces implying that they contain amphipathic alpha helical motifs. Antibodies directed against the C-terminal segment of SP-B react with the native protein in the oxidized and reduced state. Antibodies directed against the N-terminal sequence of SP-B react with the native protein only in the reduced state suggesting that this domain has a conformation dependent on disulfide bond formation.