Novel Naphthlimide Analogs And Simple Amines In The Degradation Of Nucleic Acids And Its Possible Mechanism

Because artificial nucleases can cleave nucleic acids at specific sequnce or site, it can be used as very important tools in molecular biology, can be applied to gene therapy, purity of proteins, anti-sense PCR technique, DNA footprinting and chemical probe, and so on. The research of artificial nucleases is of importance from the standpoint of biology, chemistry and medicine.Applying agarose gel electrophoresis, HPLC, DNA cloning and sequencing, ³²P-end-label and computer molecular modeling, the artifical nucleic acid cleavage activity of novel naphthlimide analogs and simples amines were researched without metal ions, the mechanism of nucleic acid degeneration is explored initially in this thesis. Four parts are included as follow:(1) The nucleic acid degradation activities of naphthlimide analogs under photo-irradiation. They have highly efficient abilities in the degradation of nucleic acids without obvious impairment on the proteins and amino acids as artificial photo-nucleases.(2) At heated condition, the nucleic acid degradation activities of naphthlimide analogs. The naphthlimide analogs can efficient hydrolyze DNA/RNA without requirement of metals and irradiation of light, and the hydrolysis is time and concentration dependent. Even, the naphthlimide analogs with concentration of μM, can efficiently catalyze the cleavage of supercoiled plasmid DNAs into half-sized fragment of the original DNA at 70℃ in the dark. Under physiological conditions, the compound C2 is applied for the degradation of λ-DNA, genomic nucleic acids from the leaf of maize, calf thymus DNA and oligo-DNA, without damage to protein.(3) DNA degradation activities of amines. The acivities of amines is investigated for they are often used to modify the naphthlimides. Some diamines and oligoamines can hydrolyze DNA at 70℃. All of their hydrolytic products are the one half-sized DNA substrates in the linear form during the degradation of DNA, while the concentration of amines is mM order. At 50℃, the activity of DNA degradation is lower than that at 70 ℃.(4) The degeneration mechanism of nucleic acid is explored preliminarily. By mean of T4 DNA ligase reaction, DNA cloning and sequencing, ³²P-end-label and computer molecular modeling, the conclusion that nucleic acids are cleaved selectively by naphthlimideanalogs through phosphodiester bond hydrolysis in GG/GC sequence, was made. And the mechanism of nucleic acid degradation was presumed.