PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9846125

Ribozyme chemogenetics.

S A Strobel
View original source ↗Export metadata ↓

Abstract

In this review I will outline several chemogenetic approaches used to determine the chemical basis of large ribozyme function and structure. The term chemogenetics was first used to describe site-specific functional group modification experiments in the analysis of DNA-protein interactions. Within the past few years equivalent experiments have been performed on large catalytic RNAs using both single-site substitution and interference mapping techniques with nucleotide analogues. While functional group mutagenesis is an important aspect of a chemogenetic approach, chemical correlates to genetic revertants and suppressors must also be realized for the genetic analogy to be intellectually valid and experimentally useful. Several examples of functional group revertants and suppressors have now been obtained within the Tetrahymena group I ribozyme. These experiments define an ensemble of tertiary hydrogen bonds that have made it possible to construct a detailed model of the ribozyme catalytic core. The model includes a functionally important monovalent metal ion binding site, a wobble-wobble receptor motif for helix-helix packing interactions, and a minor groove triple helix.

Explore related subjects

Models, MolecularMutagenesis, Site-DirectedNucleic Acid ConformationNucleotide MappingRNA, CatalyticJournal ArticleResearch Support, Non-U.S. Gov'tReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S A Strobel. 1998. Ribozyme chemogenetics.. https://doi.org/10.1002/(sici)1097-0282(1998)48%3A1%3C65%3A%3Aaid-bip7%3E3.0.co%3B2-d

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2003

The discovery of the alpha-helix and beta-sheet, the principal structural features of proteins.

PNAS papers by Linus Pauling, Robert Corey, and Herman Branson in the spring of 1951 proposed the alpha-helix and the beta-sheet, now known to form the backbones of tens of thousands of proteins. They deduced these fundamental building blocks from properties of small molecules, known both from crystal structures and from Pauling's resonance theory of chemical bonding that predicted planar peptide groups. Earlier attempts by others to build models for protein helices had failed both by including nonplanar peptides and by insisting on helices with an integral number of units per turn. In major respects, the Pauling-Corey-Branson models were astoundingly correct, including bond lengths that were not surpassed in accuracy for >40 years. However, they did not consider the hand of the helix or the possibility of bent sheets. They also proposed structures and functions that have not been found, including the gamma-helix.

Models, Molecular↗
PubMed2003

Automatic model building based on flexible fragment formalism. The case of high-resolution protein structures.

A concept of flexible fragments has been developed for automatic building of crystal structures. Six monopeptides were designed as search fragments in a phased rotation and translation function for protein building. Electron density in crystal and in molecular fragments is expanded in spherical harmonics and normalized spherical Bessel functions. A fast rotation function, which is calculated at each grid point of the asymmetric unit, is used to find the fragment orientation. Position, orientation and internal torsion angles are refined. An algorithm for chain building is simplified using generalized atoms and virtual bonds. The structure is built from molecular structure units rather than from individual atoms. A polyalanine model is built with a high accuracy at resolutions 1.2-2.1 A.

Models, Molecular↗
PubMed2003

2'-mercaptonucleotide interference reveals regions of close packing within folded RNA molecules.

The 2'-hydroxyl group makes essential contributions to RNA structure and function. As an approach to assess the ability of a mercapto group to serve as a functional analogue for the 2'-hydroxyl group, we synthesized 2'-mercaptonucleotides for use in nucleotide analogue interference mapping. To correlate the observed interference effects with tertiary structure, we used the independently folding DeltaC209 P4-P6 domain from the Tetrahymena group I intron. We generated populations of DeltaC209 P4-P6 molecules containing 2'-mercaptonucleotides located randomly throughout the domain and separated the folded molecules from the unfolded molecules by nondenaturing gel electrophoresis. Iodine-induced cleavage of the RNA molecules revealed the sites at which 2'-mercaptonucleotides interfere with folding. These interferences cluster in the most densely packed regions of the tertiary structure, occurring only at sites that lack the space and flexibility to accommodate a sulfur atom. Interference mapping with 2'-mercaptonucleotides therefore provides a method by which to identify structurally rigid and densely packed regions within folded RNA molecules.

Models, Molecular↗