Patent ID: 6627456
Filing Date: 2003-09-30
Classification: C07H,C12N,C12P,C12Q,Y10T

Abstract:
An improvement in a method for creating a ligand for a target compound, said method comprising:a) synthesizing a mixture of oligonucleotides from nucleotide building blocks each of the oligonucleotides having a region of randomized sequence, b) contacting said mixture with the target, wherein oligonucleotides having an increased affinity to the target relative to others in the mixture may be partitioned from the remainder of the mixture, c) partitioning the oligonucleotides with increased affinity from the other oligonucleotides in the mixture, d) amplifying the oligonucleotides having increased affinity in vitro to yield a mixture of oligonucleotides enriched in those with increased affinity for said target, wherein the improvement comprises including among said nucleotide building blocks those carrying nucleobases selected from the group consisting of wherein â€”R designates the point of attachment to the ribose or 2â€²-deoxyribose ring, B is selected from the group consisting of â€”H or â€”NH2, X is either a nitrogen atom or a carbon atom bearing a substituent Z, Z is an unfunctionalized lower alkyl, alkynyl, or alkyl-alkynyl chain, or a lower alkyl, alkynyl, or alkyl-alkynyl chain bearing an amino, carboxyl, hydroxy, thiol, aryl, indole, or imidazoyl group, Y is either N or CH, and the ring contains no more than three nitrogens consecutively bonded.