Sentences with phrase «of ribozymes»

Welch et al. «Expression of Ribozymes in Gene Transfer Systems to Modulate Target RNA Levels», Current Opinion in Biotechnology, 9: 486 - 496, 1998.

There are many different types of ribozymes in nature but our lab has focused upon the hammerhead motif which is found as part of the self - cleaving domain of small plant viruses.

Several genetic approaches have been taken to reduce or eliminate CCR5 expression in human cells, including the use of ribozymes [17], [18], single - chain intracellular antibodies [19], trans - dominant coreceptor mutants [20], and RNAi [21], [22].

The catalytic core of these ribozymes is formed by two structural domains.

The discovery of ribozymes not only changed our understanding of how life works today, but it also offered insights into the origin of life itself.

The data indicate that a substantial induced - fit conformational change accompanies P1 formation, and they provide a physical basis for understanding the transport of oligonucleotides to the catalytic core of the ribozyme.

In subsequent work at the Whitehead Institute and MIT, Bartel modified this type of ribozyme through tinkering and evolution.

Thus, these results directly demonstrate that divalent metal ions participate in general folding of the ribozyme tertiary structure, and further indicate a more specific involvement of Mg (II) in catalysis.

As a means of facilitating the self - replication process, the size of this ribozyme was decreased by the deletion of nonconserved structural domains; however, when such deletions were made, there were severe losses of enzymatic activity.

Not exact matches

You may wish to start by looking at the work of miller and urey, followed by some reading on prions and ribozymes.

In particular, at some point some of the RNA sequences mutated, becoming ribozymes that sped up the copying of RNA — thus adding a competitive advantage.

By this directed evolution we were able to produce ribozymes that can catalyze the copying of relatively short strands of other RNAs, although they fall far short of being able to copy polymers with their own sequences into progeny RNAs.

A catalytic RNA (ribozyme) derived from an intervening sequence (IVS) RNA of Tetrahymena thermophila will catalyze an RNA polymerization reaction in which pentacytidylic acid (C5) is extended by the successive addition of mononucleotides derived from a guanylyl -(3», 5»)- nucleotide (GpN).

Gut development and cancer, ribozymes and RNA catalysis, and the molecular genetics of muscular diseases will all be served up on the menu shortly.

Ribozymes derived from the self - splicing pre-ribosomal RNA of Tetrahymena act as sequence - specific endonucleases.

Using the atomic structures of the large ribosomal subunit fromHaloarcula marismortui and its complexes with two substrate analogs, we establish that the ribosome is a ribozyme and address the catalytic properties of its all - RNA active site.

The contribution made by individual functional groups of the G.U pair in the context of the Tetrahymena ribozyme was examined by replacement of the G.U pair with synthetic base pairs that maintain a wobble configuration, but that systematically alter functional groups in the major and minor grooves of the duplex.

The ribozyme active site also makes tertiary contacts with a tripod of 2» - hydroxyls on the minor groove surface of the splice site helix.

There are already some companies dedicated to bringing ribozymes from the laboratory to the commercial world, with potential applications as sensitive sensors of biowarfare germs or as medical diagnostic tests.

He and his team hope to prove that a ribozyme can carry out real biochemistry inside a vesicle — even if that biochemistry consists of just cutting another RNA molecule in two.

In total, the ribozyme could add on 14 nucleotides, with an accuracy of roughly 97 percent.

Unlike aptamers, which are capable only of sticking to something else, ribozymes can change the structure of other molecules.

Szostak's ribozyme could only piece together chains of RNA, each of which was several nucleotides long.

In 1993 David Bartel, then a graduate student with Szostak, produced a ribozyme that could join another piece of RNA to itself.

A reversible local folding step in which a duplex docks and undocks from the ribozyme core was observed directly in single - molecule time trajectories, allowing the determination of the rate constants and characterization of the transition state.

They tested it in a rat model of ADRP and found that after 2 to 3 months, eyes that had been injected with the virus - ribozyme combo contained 30 to 40 % more rod cells than eyes that received a dummy injection.

The therapy uses a designer ribozyme, a short strand of RNA that chops up other RNA, to seek and destroy mutant RNA before it can be used to build a protein that kills the eye's rod cells.

This ribozyme was chosen as a starting point for the design of a self - replicating RNA because of its small size.

The small size and reduced secondary structure of the selected variant results in an enhancement, relative to that of the original ribozyme, of its rate of self - copying.

Because of the retroviral packaging signal, the ribozyme would be expected to colocalize with the lacZ - containing viral genomic RNA but not with the lacZ messenger RNA.

Determination of positions where the phosphodiester backbone of the RNA is on the inside or on the outside of the molecule provides major constraints for modeling the three - dimensional structure of the Tetrahymena ribozyme.

In some prokaryotes as well as in the organelles of some eukaryotes, splicing can be self - catalyzed by particular ribozymes with the help of magnesium ions, without the intervention of any protein machinery: the group II introns ribozymes are in fact able to self - regulate their own removal from the filament, thus promoting the maturation of messenger RNA.

It was in fact believed that ribozymes resembled the functioning of protein enzymes, but that is not case: the latter in fact use far more specific methods due to the chemical richness of amino acids, whereas the process in ribozymes adapts to the skeleton of the RNA that forms them, resulting in a slightly slower but equally precise reaction mechanism.»

Cellular compartmentalization of RNAs is thought to influence their susceptibility to ribozyme cleavage.

Each captured RNAP ribozyme was then used as the starting point for another round of evolution.

After 24 rounds of this test tube evolution, in which the scientists successively upped the requirements for what a RNAP ribozyme had to do to be successful, they wound up with one called 24 - 3 polymerase.

In 1993, researchers led by Jack Szostak at Harvard University created an all - RNA version of RNAP, also known as an RNAP ribozyme, which joined two small pieces of RNA on a separate template RNA strand.

Two years ago, for example, researchers in the United Kingdom reported isolating an RNAP ribozyme capable of stitching together RNAs up to 200 nucleotides long, again when matching them up to a template strand.

The structure indicates the extent of RNA packing required for the function of large ribozymes, the spliceosome, and the ribosome.

Their announcement in 1982 of the existence of a «ribozyme» — an RNA molecule capable of catalyzing chemical reactions — upset beliefs about the nature of enzymes, but soon other catalytic RNAs were discovered.

We have exploited these ribozymes for both basic studies of RNA catalysis and for therapeutic applications.

This «hit - and - run» approach limits the requirement of chronic transgene expression and the potential leakiness of other approaches including siRNA [21], [22], intrabodies [19], and ribozymes [17].

I managed to get a great many articles in evolutionary biology (e.g., retroelements, ribozymes, phages) that way with the Proceedings of the National Academy of Sciences.