Fast Kinetics Studies of the Dynamics of TRNA Movement on the Ribosome During Bacterial Translation Elongation

Fast Kinetics Studies of the Dynamics of TRNA Movement on the Ribosome During Bacterial Translation Elongation PDF Author: Dongli Pan
Publisher:
ISBN:
Category :
Languages : en
Pages : 207

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Fast Kinetics Studies of the Dynamics of TRNA Movement on the Ribosome During Bacterial Translation Elongation

Fast Kinetics Studies of the Dynamics of TRNA Movement on the Ribosome During Bacterial Translation Elongation PDF Author: Dongli Pan
Publisher:
ISBN:
Category :
Languages : en
Pages : 207

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Kinetics of Subunit Rotation of the Ribosome During TRNA-mRNA Translocation

Kinetics of Subunit Rotation of the Ribosome During TRNA-mRNA Translocation PDF Author: Heena Sharma
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Ribosome dynamics play an essential role in orchestrating all stages of protein synthesis. Recent biochemical, structural and computational studies have shown large-scale conformational changes of the ribosome, its tRNA substrates and translation factors during the elongation phase of protein synthesis. Dynamic movements of the ribosome not only govern the translation process but are also targeted by many antibiotics resulting in inhibition of protein synthesis. Therefore, complete understanding of conformational rearrangements in the ribosome will improve our knowledge about translation me...

The Molecular Basis of Antibiotic Action

The Molecular Basis of Antibiotic Action PDF Author: Ernest Frederick Gale
Publisher: John Wiley & Sons
ISBN:
Category : Medical
Languages : en
Pages : 682

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The Role of Ribosome and TRNA Dynamics in the Regulation of Translation Elongation

The Role of Ribosome and TRNA Dynamics in the Regulation of Translation Elongation PDF Author: Wei Ning
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Protein synthesis, one of nature's most fundamental processes within all living cells, is catalyzed by the ribosome, a highly conserved, massive, two-subunit ribonucleoprotein complex. Ribosomes synthesize proteins based on the sequence of triplet-nucleotide codons presented by the messenger RNA (mRNA) template, using aminoacyl-transfer RNAs (aa-tRNAs) substrates, which deliver individual amino acids to the ribosome. Recent biochemical, structural, dynamic and computational studies have uncovered large-scale conformational changes of the ribosome, its tRNA substrates, and translation factors that play important roles in regulating protein synthesis, especially during the elongation phase of translation. For example, translocation of the ribosome along its mRNA template involves several conformational rearrangements of the ribosomal pre-translocation (PRE) complex, including the rotation of two ribosomal subunits, closure of the L1 stalk element, and reconfigurations of the ribosome-bound tRNAs.

Cell Biology by the Numbers

Cell Biology by the Numbers PDF Author: Ron Milo
Publisher: Garland Science
ISBN: 1317230698
Category : Science
Languages : en
Pages : 400

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Book Description
A Top 25 CHOICE 2016 Title, and recipient of the CHOICE Outstanding Academic Title (OAT) Award. How much energy is released in ATP hydrolysis? How many mRNAs are in a cell? How genetically similar are two random people? What is faster, transcription or translation?Cell Biology by the Numbers explores these questions and dozens of others provid

Molecular Studies of the Fidelity of Translation Elongation

Molecular Studies of the Fidelity of Translation Elongation PDF Author: Aishwarya Devaraj
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Abstract: Protein synthesis occurs in ribosomes, megadalton RNA-protein machines that use aminoacyl-tRNA (aa-tRNA) molecules to translate messenger RNA (mRNA) with high fidelity. During translation elongation, the ribosome orchestrates 3 major events: decoding, peptidyl transfer and translocation. The process of proteins synthesis is also one of the major targets of antibiotics and hence understanding the basics of ribosome function should provide insight for the development of novel drugs. Genomes are maintained and expressed with remarkable fidelity and the accuracy of each process involved represents a compromise that optimizes the evolutionary fitness of the organism. The process of translation elongation is a complex one, and therefore there are potentially many ways the process can go awry. Chapter 1 introduces translation elongation errors and discusses the differences between missense, nonsense and frameshift errors. Mutations in the ribosome and other translation factors that affect the fidelity of translation elongation are also discussed. Chapter 2 is focused on the ribosomal exit (E) site and its role in maintaining the translational reading frame. It has been proposed that a critical role for the E site is in maintenance of translational reading frame, dependent on codon-anticodon pairing (191). Though several studies support the idea that codon-anticodon interaction in the E site contributes to frame maintenance (167), direct in vivo evidence for this hypothesis has been scant. In chapter 2, we investigated this fundamental question and found that the E site helps to maintain the reading frame, but does not contribute to the accuracy of decoding, as has been suggested (chapter 2, 204). We also showed that the mutation of the 30S E site does not inhibit EF-G-catalyzed translocation, in sharp contrast to the effects of mutations in 50S E site. These data provided evidence that the function of the E site in translocation is largely confined to the 50S subunit. One of the earliest identified examples of translational frameshifting occurs in the prfB gene of E. coli, encoding the peptide release factor 2 (RF2). While the genetic studies have identified the determinants of prfB programmed frameshifting and their relative importance, how these determinants act to promote frameshifting has remained unclear. In chapter 3, we compared ribosomal complexes with various spacer lengths between the SD sequence and P codon. We found that a close juxtaposition of the SD-ASD helix and P codon strongly destabilized P-site tRNA but had little or no effect on RF2-dependent termination or EF-Tu-dependent decoding. These data suggested that the intragenic SD of prfB destabilizes pairing of peptidyl-tRNALeu to the zero-frame CUU and promotes directional movement of the mRNA template with respect to the bound tRNA. In chapter 4, we have isolated 16S rRNA mutations that could suppress a +1 frameshift mutation in E. coli. In one of the screens (where the slippery sequence in the frameshift window had a stop codon), 31 independent mutations were identified and mapped to four different positions, of which C1054U was isolated 28 times. The C1054U mutation has also been isolated previously as a nonsense suppressor. Purine substitutions at this position also increased UGA readthrough and miscoding. While the C1054U mutation significantly increased nonsense readthrough and frameshift errors, the mutation had a hyperaccurate phenotype with respect to decoding (i.e., reduced misreading). Other substitutions at this position also had differential effects on the three reporters (missense, nonsense and frameshift). These interesting observations prompted us to characterize these A-site mutations as well as others in 16S rRNA (C1200U, G1491A and G299A) in vitro to get a better understanding of how the ribosome maintains its high fidelity (chapter 5). We investigated the effect of these mutations on RF2 function and found that all of the mutations tested had a defect in RF2-dependent termination. We directly tested the effect of these mutations on decoding by measuring the rate of GTP hydrolysis in both cognate and near-cognate mRNA. We found that all of the mutations tested (C1200U, G1491A, C1054U, C1054A, and G299A) had a substantial defect in initial selection, increasing the rate of GTP hydrolysis particularly on near-cognate mRNA. We also investigated the effect of these mutations on the stability of various tRNAs in the A site. Of the mutations analyzed, C1054U and G1491A seemed to differentially affect tRNA stability, suggesting that these mutations may stimulate GTP hydrolysis in a different way than the others.

Recoding: Expansion of Decoding Rules Enriches Gene Expression

Recoding: Expansion of Decoding Rules Enriches Gene Expression PDF Author: John F. Atkins
Publisher: Springer Science & Business Media
ISBN: 0387893822
Category : Science
Languages : en
Pages : 473

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Book Description
The literature on recoding is scattered, so this superb book ?lls a need by prov- ing up-to-date, comprehensive, authoritative reviews of the many kinds of recoding phenomena. Between 1961 and 1966 my colleagues and I deciphered the genetic code in Escherichia coli and showed that the genetic code is the same in E. coli, Xenopus laevis, and guinea pig tissues. These results showed that the code has been c- served during evolution and strongly suggested that the code appeared very early during biological evolution, that all forms of life on earth descended from a c- mon ancestor, and thus that all forms of life on this planet are related to one another. The problem of biological time was solved by encoding information in DNA and retrieving the information for each new generation, for it is easier to make a new organism than it is to repair an aging, malfunctioning one. Subsequently, small modi?cations of the standard genetic code were found in certain organisms and in mitochondria. Mitochondrial DNA only encodes about 10–13 proteins, so some modi?cations of the genetic code are tolerated that pr- ably would be lethal if applied to the thousands of kinds of proteins encoded by genomic DNA.

The Eukaryotic Ribosome

The Eukaryotic Ribosome PDF Author: Heinz Bielka
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3112729757
Category : Science
Languages : en
Pages : 340

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Book Description
No detailed description available for "The Eukaryotic Ribosome".

The Ribosome

The Ribosome PDF Author: Aleksandr S. Spirin
Publisher: Springer Science & Business Media
ISBN: 3642884466
Category : Science
Languages : en
Pages : 173

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Book Description
This monograph is neither a historical outline of the development of the concepts of protein biosynthesis and the structure and functions of the ribosomes, nor an exhaustive survey of the literature on these questions. The monograph is based upon an analysis of the modern trends in this field. The purpose of the monograph was to formulate more or less generalized representations of the structure and" function of the ribosome, as we envision it at the present day. It may be that this attempt is premature for a number of reasons, and the concepts outlined here will very soon be revised. Nonetheless, despite this risk, we believe it to be advisable to undertake this attempt for the following reasons: firstly, the undertaken analysis could aid in the comprehension of the substantial mass of extremely scattered experimental data on the ribosomes presently available; secondly, in any event, even if most of the concepts outlined rapidly become obselete, they can still serve as a stimulus for a whole series of experiments; and thirdly, we hope that some of the concepts outlined will still remain essentially correct and relatively stable. In view of the aforementioned, we should make the following reservations. First of all, we made no attempt to cite all the literature on the problems discussed, but considered it sufficient to illustrate the various premises with one or several sample references.

Ribosomes Structure, Function, and Dynamics

Ribosomes Structure, Function, and Dynamics PDF Author: Marina V. Rodnina
Publisher: Springer Science & Business Media
ISBN: 3709102154
Category : Medical
Languages : en
Pages : 428

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Book Description
The ribosome is a macromolecular machine that synthesizes proteins with a high degree of speed and accuracy. Our present understanding of its structure, function and dynamics is the result of six decades of research. This book collects over 40 articles based on the talks presented at the 2010 Ribosome Meeting, held in Orvieto, Italy, covering all facets of the structure and function of the ribosome. New high-resolution crystal structures of functional ribosome complexes and cryo-EM structures of translating ribosomes are presented, while partial reactions of translation are examined in structural and mechanistic detail, featuring translocation as a most dynamic process. Mechanisms of initiation, both in bacterial and eukaryotic systems, translation termination, and novel details of the functions of the respective factors are described. Structure and interactions of the nascent peptide within, and emerging from, the ribosomal peptide exit tunnel are addressed in several articles. Structural and single-molecule studies reveal a picture of the ribosome exhibiting the energy landscape of a processive Brownian machine. The collection provides up-to-date reviews which will serve as a source of essential information for years to come.