A method for identifying nucleic acid ligands to target molecules using the SELEX procedure wherein the candidate nucleic acids contain photoreactive groups and nucleic acid ligands identified thereby are claimed. The complexes of increased affinity nucleic acids and target molecules formed in the procedure are crosslinked by irradiation to facilitate separation from unbound nucleic acids. In other methods partitioning of high and low affinity nucleic acids is facilitated by primer extension steps as shown in the figure in which chain termination nucleotides, digestion resistant nucleotides or nucleotides that allow retention of the cDNA product on an affinity matrix are differentially incorporated into the cDNA products of either the high or low affinity nucleic acids and the cDNA products are treated accordingly to amplification, enzymatic or chemical digestion or by contact with an affinity matrix.
一种利用
SELEX 程序鉴定核酸与靶分子
配体的方法,其中候选核酸含有光活性基团,并要求由此鉴定核酸
配体。在该程序中形成的亲和力增强的核酸和靶分子的复合物通过辐照交联,以便于与未结合的核酸分离。在其他方法中,高亲和力核酸和低亲和力核酸的分离是通过引物延伸步骤来促进的,如图所示,其中链终止核苷酸、抗消化核苷酸或可使 cDNA 产物保留在亲和基质上的核苷酸被不同地掺入高亲和力核酸或低亲和力核酸的 cDNA 产物中,cDNA 产物被相应地放大、酶解或
化学消化或与亲和基质接触来处理。