ribozyme


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Ribozyme

A ribonucleic acid (RNA) molecule that, like a protein, can catalyze specific biochemical reactions. Examples include self-splicing rRNA and RNase P, both involved in catalyzing RNA processing reactions (that is, the biochemical reactions that convert a newly synthesized RNA molecule to its mature form). Different ribozyme structures catalyze quite distinct RNA processing reactions, just as protein enzyme families that are composed of different structures catalyze different types of biochemical reactions.

Ribozymes share many similarities with protein enzymes, as assessed by two parameters that are used to describe a biological catalyst. The Michaelis-Menten constant Km relates to the affinity that the catalyst has for its substrate, and ribozymes possess Km values which are comparable to Km values of protein enzymes. The catalytic rate constant describes how efficiently a catalyst converts substrate into product. The values of this constant for ribozymes are markedly lower than those values observed for protein enzymes. Nevertheless, ribozymes accelerate the rate of chemical reaction with specific substrates by 1011 compared with the rate observed for the corresponding uncatalyzed, spontaneous reaction. Therefore, ribozymes and protein enzymes are capable of lowering to similar extents the activation energy for chemical reaction. See Enzyme, Protein, Ribonucleic acid (RNA)

ribozyme

[′rīb·ə‚zīm]
(biochemistry)
A ribonucleic acid molecule that can catalyze, or lower the activation energy for, specific biochemical reactions.
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The team also showed that the new ribozyme could work without hindrance even when same-handed RNA nucleotides were present.
Previous research by Liu and Lu showed that Salmonella could effectively sneak the anti-viral ribozymes into human cells infected with human cytomegalovirus and reduce the viral load of the cell cultures.
Certain types of RNA called ribozymes are capable of both storing genetic information and catalyzing chemical reactions--two necessary features in the formation of life, said Jeremy Smith, who directs the laboratory's Center for Molecular Biophysics and led the research.
To study ribozyme-mediated anti-Vif activity in cell culture, each ribozyme was moved into the retroviral vector, pSuper.
However, we believe that the second mechanism may be advantageous to synthesize large RNA by primitive catalytic RNA, and ribozymes with RNA ligation activity might have been an essential catalytic activity in t he RNA world.
This hypothesis needs to be examined in light of the null hypothesis: that modern, viral tRNA tags were invented by opportunistic viruses at some time following the reign of ribozymes.
The ribozyme mimic is designed to be a catalyst that cannot destroy itself, but can destroy many copies of the targeted RNA.
Also in 1991, Cech's laboratory reported similar activity in ribozymes.
The research team found a theoretical explanation for why the Diels-Alder ribozyme needs magnesium to function.
But the discovery that RNA can be an enzyme, dubbed a ribozyme, potentially able to boost its own replication, led to fresh ideas about how life might have started.
Hammerhead ribozyme design, based on the Hasseloff and Gerlach model (9), consists of two flanking regions that provide target specificity by Watson-Crick base pairing and a catalytic core that cleaves at the target site.
This project involved the design and synthesis of a catalytic hammerhead ribozyme targeted to the GUA sequence at nucleotide 6134 of the HIV-1 NL43 Vpu gene.