THE DE-NOVO PROTEIN WITH GRAFTED BIOLOGICAL FUNCTION - TRANSFERRING OF INTERFERON BLAST-TRANSFORMING ACTIVITY TO ALBEBETIN

The de novo protein albebetin has been designed recently to form a pre determined tertiary fold that has not yet been observed in natural pro teins, An eight amino acid fragment (131-138) of human interferon alph a(2) carrying the blast-transforming activity of the protein was attac hed to the N-terminus of albebetin next to its initiatory methionine r esidue. The gene of chimeric protein was expressed in a wheat germ cel l-free translation system and synthesized protein was tested for its c ompactness and stability. Its ability for receptor binding was also st udied, We have shown that albebetin with attached octapeptide is pract ically as compact as natural proteins of corresponding molecular weigh t and possesses high stability toward the urea-induced unfolding, It b inds murine thymocyte receptor at a high affinity and activates the th ymocyte blast transformation efficiently at a concentration of 10(-11) M.