Hct. Guo et Ra. Collins, EFFICIENT TRANS-CLEAVAGE OF A STEM-LOOP RNA SUBSTRATE BY A RIBOZYME DERIVED FROM NEUROSPORA VS RNA, EMBO journal, 14(2), 1995, pp. 368-376
We have constructed a ribozyme containing 144 nucleotides of Neurospor
a VS RNA that can catalyze the cleavage of a separate RNA in a true en
zymatic manner (K-m approximate to 0.13 mu M, k(cat) approximate to 0.
7/min). Comparison of the rates of cis- and trans-cleavage, as well as
the lack of effect of pH on the rate of cleavage, suggest that a rate
-limiting step, possibly a conformational change, occurs prior to clea
vage. The minimum contiguous substrate sequence required for cleavage
consists of one nucleotide upstream and 19 nucleotides downstream of t
he cleavage site. Unlike most other ribozymes which interact with long
single-stranded regions of their substrates, the minimal substrate fo
r the VS ribozyme consists mostly of a stable stem-loop, which would a
ppear to preclude its recognition simply via extensive Watson-Crick ba
se pairing.