Four types of β-carboline–nucleoside conjugates were synthesized. The binding affinities of these β-carboline–nucleoside conjugates 4–11, 13 and 15 to TAR RNA were evaluated by affinity capillary electrophoresis. The data of binding affinities to TAR RNA show that conjugates 9 and 13 are stronger binders than the parent compound MC3. Computer modeling indicates that the β-carboline–nucleoside conjugate 13 can fit to the UCU three- ...