Bacterial ribonuclease P reaction is affected by substrate shape and magnesium ion concentration.

Bacterial RNase P is a ribonucleoprotein enzyme which cleaves 5'-precursor sequence of pre-tRNA for pre-tRNA maturation. The RNA component of bacterial RNase P is ribozyme. It recognizes cloverleaf shaped pre-tRNA and hairpin RNA with a CCA-3' tag sequence as its substrates. Previously, we reported that the substrate recognition of the E. coli RNase P ribozyme depends on the concentration of magnesium ion in vitro. In this report, we examined the substrate shape preference of the Bacillus subtilis RNase P ribozyme and compared it with that of the E. coli ribozyme. The results of the B. subtilis ribozyme displayed same tendency as the E. coli ribozyme. We also examined the effect of the protein component of the E. coli RNase P. Under the conditions tested, magnesium ion concentration dependency to substrate shape recognition was not observed when the holo enzyme was used.