Uwe Krüger

Synthesis and structural characterization of human-identical lung surfactant SP-C protein.

An efficient synthesis for human‐identical lung surfactant protein SP‐C is described with a semi‐automated solid phase synthesizer using Fmoc chemistry. Double coupling and acetic anhydride capping procedures were employed for synthetic cycles within the highly hydrophobic C‐terminal domain of SP‐C. Isolation of the protein was performed by mild cleavage and deprotection conditions and subsequent HPLC purification yielding a highly homogeneous protein as established by sequence determination, electrospray, plasma desorption and MALDI mass spectrometry. A general method has been employed for the preparation of Cys‐palmitoylated protein by using temporary Cys(tButhio) protection, in situ deprotection with β‐mercaptoethanol and selective palmitoylation of resin‐bound SP‐C. The mild synthesis and isolation conditions provide SP‐C with a high α‐helical content, comparable to that of the natural SP‐C, as assessed by CD spectra. Furthermore, first biophysical data indicate a surfactant activity comparable to that of the natural protein.