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Biomedical subjects

N R Pace

Publications and source records attributed to N R Pace.

156 records · Page 9Linked to original sources
PubMed1967

Examination of the Qbeta-replicase reaction by sucrose gradient and gel electrophoresis.

The products of an in vitro synthesis with the Qbeta replicase purified from Escherichia coli infected by the ribonucleic acid (RNA) bacteriophage Qbeta were examined by sucrose gradient centrifugation and polyacrylamide gel electrophoresis. It was found that, in contrast to sucrose gradients, gel electrophoresis clearly resolved four classes in the newly synthesized RNA. The product was found to contain mature Qbeta-RNA and small-molecular-weight RNA. In addition, two species were identified which corresponded to the structures found in vivo by Francke and Hofschneider and by Franklin. All of the participants implicated in RNA replication by in vivo studies have now been synthesized in vitro and isolated from the reaction mixture.

Centrifugation, Density Gradient↗
PubMed1966

In vitro synthesis of an infectious mutant RNA with a normal RNA replicase.

When purified Qbeta-RNA replicase is presented alternately with two genetically different Qbeta-RNA molecules, the RNA synthesized is identical to the initiating template. The results establish that the RNA is the instructive agent in the replicative process and hence that it satisfies the operational definition of a self-duplicating entity. The data also eliminate alternative explanations which do not involve self-propagation of the input RNA. An opportunity is now provided for studying the genetics and evolution of a self-duplicating nucleic acid molecule under conditions permitting detailed control of environmental parameters and chemical components.

Centrifugation↗
PubMedDate not supplied

Analysis of the tertiary structure of bacterial RNase P RNA.

The ubiquitous occurrence of ribonuclease P (RNase P) as a ribonucleoprotein and the catalytic properties of bacterial RNase P RNAs indicate that RNA fulfills an ancient and important role in the function of this enzyme. This review focuses on efforts to determine the structure of the bacterial RNase P RNA ribozyme. Phylogenetic comparative analysis of a library of bacterial RNase P RNA sequences has resulted in a well-developed secondary structure model and allowed identification of some elements of tertiary structure. The native structure has been redesigned by circular permutation to facilitate intra- and inter-molecular crosslinking experiments in order to gain further structural information. The crosslinking constraints, together with the constraints provided by comparative analyses, have been incorporated into a first-order model of the structure of of the ribozyme-substrate complex. The developing structural perspective allows the design of self-cleaving pre-tRNA-RNase P RNA conjugates which are useful tools for additional structure-probing experiments.

Bacteria↗