Synthesis of DNA and RNA fragments with a guanine thioalkyl tether, and synthesis of [2-carbon-13,amino radical-nitrogen-15,6-oxygen-18]-deoxyguanosine

Two different types of modified nucleosides were synthesized to facilitate the understanding of DNA and RNA biological function. Chapter 2 describes the synthesis of DNA and RNA fragments containing a modified guanosine with a protected thioalkyl tether, which can be converted to three different crosslinkable groups after oligonucleotide synthesis. These DNA and RNA fragments are being used to crosslink with HIV-1 RT for X-ray crystallography studies in Dr. Edward Arnold's laboratory.;A new synthetic route was also developed to make [2-13C,NH 2-15N,6-18O]-deoxyguanosine, which can be incorporated into DNA using phosphoramidite chemistry. The 13C and 15N site-specific labeling can provide information about local DNA interactions in 13C and 15N NMR experiments. These two labels together with the 18O also offer a modified nucleoside that can serve as a M+4 mass tag for deoxyguanosine.