Patent RU-2198931-C2 (RU)
Title: Method of identification of ligands, method of antibody preparing, method of selection of nucleic acid, method of nucleic acids mixture preparing, mixture of nucleic acids, nucleic acid ligand no occurring in nature
Inventor: GOULD LARRI
IPC: C12Q1/68
Filed: 1991-06-10
Granted: 2003-02-20
Abstract: FIELD: molecular biology, biochemistry. SUBSTANCE: invention relate to novel class of nucleic acids ligands with high affinity degree that bind with essential molecule-target specifically. Method involves interaction of a mixture of single-stranded nucleic acids with target, separation of nucleic acids exhibiting enhanced affinity to this target from mixture remained. After separation of nucleic acids exhibiting enhanced affinity to this target amplification is carried out to obtain ligand-enriched mixture of nucleic acids and interaction of single-stranded nucleic acids with target is provided. Nucleic acids exhibiting enhanced affinity to this target are separated and their amplification is carried out to obtain ligand- enriched mixture of nucleic acids. The above enumerated stages are repeated using ligand-enriched mixture of nucleic acids after each following repeat as many times as necessary to obtain the enrichment level that is sufficient for preparing ligand solution to indicated target. Nucleic acid molecules that effect on function of molecule-target are identified by the above-mentioned method and tested for enhanced affinity to target to be interested and for their capacity to effect on functions of indicated molecule-targets. Mixture of nucleic acids comprising conservative segment and randomized segment is prepared. Interaction of mixture of nucleic acids with target is carried out under conditions favorable for binding with formation of pairs "nucleic acid target" and unbound nucleic acids. Unbound nucleic acids are separated from pair "nucleic acid target" and amplification of separated nucleic acid pairs "nucleic acid target" is carried out to obtain ligand-enriched mixture of nucleic acids. Mixture of nucleic acids comprises at least 10 9  of single- stranded nucleic acids. Nucleic acids comprise conservative nucleotide fragment and randomized nucleotide fragment. Randomized segment comprises chain of 8-100 following one after another nucleotides. Nucleic acid ligand no occurring in nature is identified by method given above. Ligand is not nucleic acid exhibiting the known physiological binding function by molecule-target and shows affinity for specific binding with molecule- target. Such molecule-target has tree-dimensional structure distinguishing from polynucleotide structure binding with indicated nucleic acid ligand by mechanism depending on base pairing by Watson-Crick model or by triple helix binding. Base sequences of nucleic acids and ribonucleic acids are given in the invention claim and in description. Invention allows to prepare the novel class of nucleic acids compounds, i. e. so called nucleic acid antibodies that exhibit affinity for specific binding with three-dimensional molecule-targets. EFFECT: improved methods of identification, preparing and selection of nucleic acids. 83 cl, 35 dwg, 13 tbl, 13 ex