[Synthesis and properties of oligonucleotide derivatives containing chemical active ureido groups]

The 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide (EDC)-induced modification of the carboxyl group in a synthetic oligodeoxyribonucleotide was studied. Treatment of a carboxyl-containing oligonucleotide with EDC in water or aqueous buffer solutions leads to the rapid formation (with a 80-90% yield) of the corresponding ureido derivative, which can easily be isolated by PAGE. These derivatives are stable in neutral and weakly acid aqueous solutions, whereas under weakly basic conditions they efficiently (50-90%) acylate amino groups. Reagents of this type can be used for affinity modification of enzymes and other proteins and for preparing conjugates of oligonucleotides with other compounds.