The discovery of a catalytic RNA within RNase P and its legacy.

Sidney Altman's discovery of the processing of one RNA by another RNA that acts like an enzyme was revolutionary in biology and the basis for his sharing the 1989 Nobel Prize in Chemistry with Thomas Cech. These breakthrough findings support the key role of RNA in molecular evolution, where replicating RNAs (and similar chemical derivatives) either with or without peptides functioned in protocells during the early stages of life on Earth, an era referred to as the RNA world. Here, we cover the historical background highlighting the work of Altman and his colleagues and the subsequent efforts of other researchers to understand the biological function of RNase P and its catalytic RNA subunit and to employ it as a tool to downregulate gene expression.

Trials, travails and triumphs: an account of RNA catalysis in RNase P.

Last December marked the 20th anniversary of the Nobel Prize in Chemistry to Sidney Altman and Thomas Cech for their discovery of RNA catalysts in bacterial ribonuclease P (an enzyme catalyzing 5' maturation of tRNAs) and a self-splicing rRNA of Tetrahymena, respectively. Coinciding with the publication of a treatise on RNase P, this review provides a historical narrative, a brief report on our current knowledge, and a discussion of some research prospects on RNase P.

Surprising contribution to aminoacylation and translation of non-Watson-Crick pairs in tRNA.

Molecules of transfer RNA (tRNA) typically contain four stems composed of Watson-Crick (W-C) base pairs and infrequent mispairs such as G-U and A-C. The latter mispairs are fundamental units of RNA secondary structure found in nearly every class of RNA and are nearly isomorphic to W-C pairs. Therefore, they often substitute for G-C or A-U base pairs.

Structure-function analysis of tRNA(Gln) in an Escherichia coli knockout strain.

The diverse and highly specific interaction between RNAs and proteins plays an essential role in many important biological processes. In the glutamine aminoacylation system, crystal structures of the free and ligated macromolecules have provided a description of the tRNA-protein interactions at the molecular level. This data lays the foundation for genetic, biochemical, and structural analyses to delineate the set of key interactions that governs the structure-function relationships of the two macromolecules.

Aptamer redesigned tRNA is nonfunctional and degraded in cells.

An RNA aptamer derived from tRNA(Gln) isolated in vitro and a rationally redesigned tRNA(Gln) were used to address the relationship between structure and function of tRNA(Gln) aminoacylation in Escherichia coli. Two mutant tRNA(Gln) sequences were studied: an aptamer that binds 26-fold tighter to glutaminyl-tRNA synthetase than wild-type tRNA(Gln) in vitro, redesigned in the variable loop, and a mutant with near-normal aminoacylation kinetics for glutamine, redesigned to contain a long variable arm. Both mutants were tested in a tRNA(Gln) knockout strain of E.

Recognition of acceptor-stem structure of tRNA(Asp) by Escherichia coli aspartyl-tRNA synthetase.

Protein-RNA recognition between aminoacyl-tRNA synthetases and tRNA is highly specific and essential for cell viability. We investigated the structure-function relationships involved in the interaction of the Escherichia coli tRNA(Asp) acceptor stem with aspartyl-tRNA synthetase. The goal was to isolate functionally active mutants and interpret them in terms of the crystal structure of the synthetase-tRNA(Asp) complex.

Genetic perturbations of RNA reveal structure-based recognition in protein-RNA interaction.

Protein-RNA recognition is an essential foundation of cellular processes, yet much remains unknown about these important interactions. The recognition between aminoacyl-tRNA synthetases and their cognate tRNA substrates is highly specific and essential for cell viability, due to the necessity for accurate translation of the genetic code into protein sequences. We selected an active tRNA that is highly mutated in the recognition nucleotides of the acceptor stem region in the alanine system.