Alterations of the C-terminal end do not affect in vitro or in vivo activity of surfactant protein C analogs

► Secondary structure and orientation of surfactant protein C analog SP-C33 in a DPPC membrane is equal to that of native SP-C. ► C-terminal modifications of SP-C33 do not alter its surfactant activity. ► C-terminal truncation of SP-C33 does not affect its surfactant activity.