CONJUGATES OF OLIGONUCLEOTIDES WITH POLYAROMATIC FLUOROPHORES AS PROMISING DNA PROBES

Conjugates of pyrene and perylene with oligodeoxynucleotides were synt hesized and tested as hybridisation probes. A 13-mer containing a 3-pe ryleneacetic acid residue attached to the 5' end through a hexamethyle nediamine linker showed no response in the fluorescent spectrum upon h ybridisation to the complementary sequence. At the same time, pyrene-l abelled probes are sensitive to duplex formation. A pyrene pseudonucle otide unit based on 4-(1-pyrenyl)-1,3-butanediol can be introduced int o any predetermined position(s) of the oligonucleotide chain. The prob es polylabelled in this fashion displayed considerable changes in the excimer-to-monomer fluorescence intensity ratio after duplex formation . The internal location of two pyrene residues in the probe provides a drastic enhancement of excimer fluorescence ( similar to 470 nm) upon hybridisation. When two pyrene units were brought into close proximit y to two pyrenes in the complementary strand upon duplex formation, st rong excimer emission at similar to 450 nm was detected. This effect p rovides a basis for a sensor construction designed to detect nucleic a cid hybridisation. (C) 1998 Elsevier Science S.A. All rights reserved.