Chemical-enzymatic synthesis of biologically active DNA fragments.

In this communication we report our recent investigations concerned the design and construction of synthetic functionally active DNA fragments: the structural gene for pentapeptide Leu-enkephalin and the double-stranded 93 base pairs long polynucleotide representing the promoter region of bacteriophage fd DNA. The ways for synthesis of modified promoter analogs carrying photosensitive residues of 5-bromodeoxyuridine in different positions of the chain are also considered.