Ribonucleotide Reductase PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Ribonucleotide Reductase PDF full book. Access full book title Ribonucleotide Reductase by Kristoffer Andersson. Download full books in PDF and EPUB format.
Author: Kristoffer Andersson
Publisher: Nova Publishers
ISBN: 9781604561999
Category : Science
Languages : en
Pages : 236
Get Book Here
Book Description
The subject of this book is the amazing enzyme ribonucleotide reductase (RNR), the enzyme responsible for the conversion of ribonucleotides to deoxyribonucleotides. The prerequisite for DNA-synthesis and DNA-repair in all living cells is the supply of the four deoxyribonucleotides. Such molecules result from the enzymatically difficult radical-induced reduction of ribonucleotides, a multistep chemical process catalyzed by RNR. RNR was the first enzyme in which the presence of an amino acid radical (a tyrosyl) in E. coli Class Ia RNR has been proven; since then several other biological amino acid radical species have been found on e.g. tryptophan, glycine, cysteine, lysine residues and on amino acid derived small cofactors like 2 tryptophanes in thryptophan-trypthanyl-radical or cysteine-tyrosyl-radical in other enzymes. As all known cellular life forms store their genetic information as DNA, RNR is likely to be found in all growing cells of every living organism, a fact that is confirmed by a rapidly increasing number of genomic screenings.
Author: Kristoffer Andersson
Publisher: Nova Publishers
ISBN: 9781604561999
Category : Science
Languages : en
Pages : 236
Get Book Here
Book Description
The subject of this book is the amazing enzyme ribonucleotide reductase (RNR), the enzyme responsible for the conversion of ribonucleotides to deoxyribonucleotides. The prerequisite for DNA-synthesis and DNA-repair in all living cells is the supply of the four deoxyribonucleotides. Such molecules result from the enzymatically difficult radical-induced reduction of ribonucleotides, a multistep chemical process catalyzed by RNR. RNR was the first enzyme in which the presence of an amino acid radical (a tyrosyl) in E. coli Class Ia RNR has been proven; since then several other biological amino acid radical species have been found on e.g. tryptophan, glycine, cysteine, lysine residues and on amino acid derived small cofactors like 2 tryptophanes in thryptophan-trypthanyl-radical or cysteine-tyrosyl-radical in other enzymes. As all known cellular life forms store their genetic information as DNA, RNR is likely to be found in all growing cells of every living organism, a fact that is confirmed by a rapidly increasing number of genomic screenings.
Author:
Publisher:
ISBN: 9781607411635
Category : Enzymes
Languages : en
Pages : 99
Get Book Here
Book Description
Author: Eduard Torrents
Publisher: Nova Science Publishers
ISBN: 9781606924198
Category : Enzymes
Languages : en
Pages : 0
Get Book Here
Book Description
Ribonucleotide reductase (RNR), a universal enzyme present in essentially all living cells and organisms, has a central role in DNA replication and repair by catalysing production of deoxyribonucleotides from the corresponding ribonucleotides. Three major classes of RNRs are known, differing in their cofactor requirements: class I RNRs (with subclasses Ia and Ib) carry a stable tyrosyl radical and are oxygen-dependent, class II RNRs require the vitamin B12 cofactor 5'-deoxyadenosylcobalamin and are oxygen-independent, and class III RNRs carry a stable glycyl radical and are oxygen-sensitive. Despite these differences, all classes have a similar reaction mechanism and the same highly specific catalytic core structure, indicating that they evolved from a common ancestor. Biochemical studies of RNRs from selected model organisms in combination with the vast number of deduced RNR sequences from publicly available complete genomic sequences show that whereas eukaryotes and their viruses with few exceptions contain only class Ia RNRs, all three major RNR classes are found among prokaryotes and bacteriophages and quite often one organism encodes more than one class of RNR. They are compiled in an open access database, called RNRdb for Ribonucleotide Reductase database that is available at http://rnrdb.molbio.su.se. RNRs are produced in a strictly controlled way depending upon growth phase and environmental cues. The authors describe a comprehensive summary of how the expression of RNR genes is regulated in several eubacterial organisms and in yeast. Due to RNR's importance for the realisation of DNA replication, it has been recognised as a possible target for antiproliferative therapy. The authors present a comprehensive summary of RNR-specific inhibitors that have reached clinical trials and/or are currently used in clinical therapy.
Author: Eduard Torrents
Publisher:
ISBN: 9781607416708
Category : Enzymes
Languages : en
Pages : 99
Get Book Here
Book Description
Author: Satya P. Gupta
Publisher: Springer Science & Business Media
ISBN: 3642381111
Category : Science
Languages : en
Pages : 314
Get Book Here
Book Description
Satya P. Gupta's Hydroxamics Acids is the first book to compile invited articles written by international experts on the class of compounds hydroxamic acids. Found to possess a wide spectrum of biological activities, the hydroxamic acids are of interest to theoretical and experimental chemists who can study and make use of them in drug design and development. Chapters in this book provide a diverse and comprehensive coverage of this compound class and consequently this publication is a valuable resource for researchers in chemical, pharmaceutical and biological sciences.
Author: Judith P. Klinman
Publisher: Gulf Professional Publishing
ISBN: 9780120342587
Category : Medical
Languages : en
Pages : 502
Get Book Here
Book Description
A cofactor is a component part of many enzymes and functions by uniting with another molecule in order to become active. The use of cofactors to supplement the native amino acids of a protein is essential to maintain the chemical capabilities necessary for organisms to survive. This volume focuses on the significant advances of the past decade in identifying and describing new cofactors--either small molecules or those derived posttranslationally.
Author: J. Frank Henderson
Publisher: Academic Press
ISBN: 1483261158
Category : Science
Languages : en
Pages : 323
Get Book Here
Book Description
Nucleotide Metabolism: An Introduction is a textbook exclusively focusing on the study of the aspects of nucleotide metabolism. The book intends to present the chemistry and metabolism of nucleotides, one of the oldest subjects of biochemistry. The text is divided in two parts. Part I considers the general aspects of nucleotide metabolism such as the history of the discovery of nucleotides; functions of nucleotides in cells; and group-transfer reactions during nucleotide metabolism. Part II deals with the synthesis, formation, and conversion of purine ribonucleotides. Biochemists, pharmacologists, and researchers in the fields of medicine and pharmaceuticals will find the book invaluable.
Author: Manfred Schwab
Publisher: Springer Science & Business Media
ISBN: 3540368477
Category : Medical
Languages : en
Pages : 3307
Get Book Here
Book Description
This comprehensive encyclopedic reference provides rapid access to focused information on topics of cancer research for clinicians, research scientists and advanced students. Given the overwhelming success of the first edition, which appeared in 2001, and fast development in the different fields of cancer research, it has been decided to publish a second fully revised and expanded edition. With an A-Z format of over 7,000 entries, more than 1,000 contributing authors provide a complete reference to cancer. The merging of different basic and clinical scientific disciplines towards the common goal of fighting cancer makes such a comprehensive reference source all the more timely.
Author: Gyunghoon Kang
Publisher:
ISBN:
Category :
Languages : en
Pages : 178
Get Book Here
Book Description
Ribonucleotide reductase (RNR) catalyzes the reduction of nucleotides to their 2'-deoxynucleotide counterparts. The class la RNR from Escherichia coli is composed of two homodimeric subunits [alpha]2 and [beta]2 that form an [alpha]2[beta]2 complex to perform nucleotide reduction. Chemistry is initiated by a thiyl-radical (C439·) in the active site of [beta]2 that is reversibly generated by a diferric-tyrosyl radical cofactor (Y122·) in [beta]2 by a series of proton-coupled electron transfer steps: Y122[beta] - [W48[beta]] - Y356[beta] - Y731[alpha] - Y730[alpha] - C439[alpha]. A high-resolution structure of the active [alpha]2[beta]2 complex has long eluded the field due to the weak and transient nature of the a2-P2 interaction. Previous studies revealed that perturbing radical transfer by incorporating unnatural amino acids along the transfer pathway, or by using mechanistic inhibitors that trap the radical in the active site, can extend the lifetime of the [alpha]2[beta]2 complex, allowing for structural studies. Here, we present our efforts to study the E. coli class la RNR [alpha]2[beta]2 complex, trapped using these different perturbation methods, using cryo-electron microscopy. The two [alpha]2[beta]2 structures presented here provide deeper insight into the structural dynamics of nucleotide reduction. We end with a brief discussion of class la RNR from T4 bacteriophage, which despite sharing high sequence identity to its host E. coli class la RNR, employs a very different mode of oligomeric regulation.
Author: Lluis Ribas de Pouplana
Publisher: Springer Science & Business Media
ISBN: 0387268871
Category : Science
Languages : en
Pages : 266
Get Book Here
Book Description
Early Thoughts on RNA and the Origin of Life The full impact of the essential role of the nucleic acids in biological systems was forcefully demonstrated by the research community in the 1950s. Although Avery and his collaborators had identified DNA as the genetic material responsible for the transformation of bacteria in 1944, it was not until the early 1950s that the Hershey-Chase experiments provided a more direct demonstration of this role. Finally, the structural DNA double helix proposed by Watson and Crick in 1953 clearly created a structural frame work for the role of DNA as both information carrier and as a molecule that could undergo the necessary replication needed for daughter cells. Research continued by Kornberg and his colleagues in the mid-1950s emphasized the biochemistry and enzymology of DNA replication. At the same time, there was a growing interest in the role of RNA. The 1956 dis covery by David Davies and myself showed that polyadenylic acid and polyuridylic acid could form a double-helical RNA molecule but that it differed somewhat from DN A A large number of experiments were subsequendy carried out with synthetic polyribonucleotides which illustrated that RNA could form even more complicated helical structures in which the specificity of hydrogen bonding was the key element in determining the molecular conformation. Finally, in I960,1 could show that it was possible to make a hybrid helix.
