Evidence for proton transfer in the rate-limiting step of a fast-cleaving Varkud satellite ribozyme
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چکیده
منابع مشابه
Exceptionally fast self-cleavage by a Neurospora Varkud satellite ribozyme.
Most of the small ribozymes, including those that have been investigated as potential therapeutic agents, appear to be rather poor catalysts. These RNAs use an internal phosphoester transfer mechanism to catalyze site-specific RNA cleavage with apparent cleavage rate constants typically <2 min(-1). We have identified variants of one of these, the Neurospora Varkud satellite ribozyme, that self-...
متن کاملThe structure and active site of the Varkud satellite ribozyme.
The Varkud satellite ribozyme is the largest of the small nucleolytic ribozymes, and the only one for which there is no crystal structure. It can be divided into a trans -acting ribozyme, consisting of five helices organized by two three-way helical junctions, and a stem-loop substrate with which it interacts, primarily by tertiary interactions. We have determined the global fold of the ribozym...
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............................................................................................................. viii CHAPTER 1: EXPLORATION OF HOW RNA FUNCTIONS IN THE CHEMISTRY OF LIFE ......................................................................... 1 1.
متن کاملThe rate-limiting step in the folding of a large ribozyme without kinetic traps.
A fundamental question in RNA folding is the nature of the rate-limiting step. Folding of large RNAs often is trapped by the need to undo misfolded structures, which precludes the study of the other, potentially more interesting aspects in the rate-limiting step, such as conformational search, metal ion binding, and the role of productive intermediates. The catalytic domain of the Bacillus subt...
متن کاملInvolvement of a cytosine side chain in proton transfer in the rate-determining step of ribozyme self-cleavage.
Ribozymes of hepatitis delta virus have been proposed to use an active-site cytosine as an acid-base catalyst in the self-cleavage reaction. In this study, we have examined the role of cytosine in more detail with the antigenomic ribozyme. Evidence that proton transfer in the rate-determining step involved cytosine 76 (C76) was obtained from examining cleavage activity of the wild-type and imid...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 2007
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.0608864104