The pulmonary surfactant prevents alveolar collapse and is required for normal pulmonary function. One of the important components of the surfactant besides phos-pholipids is surfactant-associated protein C (SP-C). SP-C shows complex oligomerization behavior and a transition to b-amyloid-like fibril structures, which are not yet fully understood. Besides this nonspecific oligomerization, MS and chemical cross-linking data combined with CD spectra provide evidence of a specific, mainlya-helical, dimer at lowto neutral pH
