Design and development of a catalytic ribonucleoprotein

Ribonucleoproteins (RNPs) consisting of derivatives of a ribozyme and an RNA‐binding protein were designed and constructed based upon high‐resolution structures of the corresponding prototype molecules, the Tetrahymena group I self‐splicing intron RNA and two proteins (bacteriophage λN and HIV Rev proteins) containing RNA‐binding motifs. The splicing reaction proceeds efficiently only when the designed RNA associates with the designed protein either in vivo or in vitro. In vivo mutagenic protein selection was effective for improving the capability of the protein. Kinetic analyses indicate that the protein promotes RNA folding to establish an active conformation. The fact that the conversion of a ribozyme to an RNP can be accomplished by simple molecular design supports the RNA world hypothesis and suggests that a natural active RNP might have evolved readily from a ribozyme.