BIOSYNTHETIC INCORPORATION AND CHEMICAL MODIFICATION OF ALKENE FUNCTIONALITY IN GENETICALLY-ENGINEERED POLYMERS

Repetitive polypeptides of sequence [(AlaGly)(3)ProGluGly](16), 3a, ha ve been prepared in Escherichia coli as overexpressed recombinant prot eins. Replacement of more than 90% of the naturally occurring proline (Pro) residues with 3,4-dehydroproline (Dhp) in sequence 3a was achiev ed by in vivo expression of the target protein in medium containing Dh p and lacking Pro. The resulting material (3b) was treated with H2O2 o r Br-2 to yield polymers containing 3,4-dihydroxyproline (Dhy, 3c) and 3,4-dibromoproline (Dbr, 3d), respectively, in place of the Dhp resid ue. These results represent the first demonstration of the incorporati on and modification of alkene functionality in recombinant proteins.