De novo design, synthesis and study of albebetin, a polypeptide with a predetermined three-dimensional structure. Probing the structure at the nanogram level.

The de novo polypeptide named albebetin was designed to form the tertiary fold that has not yet been observed in natural proteins. The design was based on the molecular theory of protein structures. The gene coding for this polypeptide was chemically synthesized. For the initial characterization of a protein structure, a new approach has been developed that uses only nanogram amounts of a polypeptide without its previous purification. This approach includes the biosynthesis of radiolabeled protein in a cell-free translation system with subsequent analysis of its compactness and structure by size-exclusion chromatography, urea-gradient electrophoresis and limited proteolysis. According to all tests used, albebetin has a compact stable structure.