Abstract
Several mutants for the minus strands of the self-cleaving domain of the satellite RNA of tobacco ringspot virus have been synthesized by joining chemically synthesized oligoribonucleotides with RNA ligase. Kinetic properties of the enzyme strands (50 nucleotides) against substrates (15-mer and 18-mer) were investigated. Structural properties of the unpaired part in the cleavage region were estimated from mutagenesis. The catalytic domain alone was proved to be responsible for the rejoining reaction of cleaved substrates. It was also found that the ribozyme could be divided into two strands without loss of activity. Effects of concentration of magnesium ion and polyamines on the cleavage reaction for the two-stranded ribozyme are also reported.