An improved method is presented for the preparation
of milligram quantities of homogenous-length RNAs suitable
for nuclear magnetic resonance or X-ray crystallographic
structural studies. Heterogeneous-length RNA transcripts
are processed with a hammerhead ribozyme to yield homogenous-length
products that are then readily purified by anion exchange
high-performance liquid chromatography. This procedure
eliminates the need for denaturing polyacrylamide gel electrophoresis,
which is the most laborious step in the standard procedure
for large-scale production of RNA by in vitro transcription.
The hammerhead processing of the heterogeneous-length RNA
transcripts also substantially improves the overall yield
and purity of the desired RNA product.