Molecular Biology of the Cell

Molecular Biology of the Cell PDF Author:
Publisher:
ISBN: 9780815332183
Category : Cells
Languages : en
Pages : 0

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Molecular Biology of the Cell

Molecular Biology of the Cell PDF Author:
Publisher:
ISBN: 9780815332183
Category : Cells
Languages : en
Pages : 0

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Book Description


Intracellular Protein Degradation

Intracellular Protein Degradation PDF Author: A.J. Rivett
Publisher: Elsevier Science
ISBN: 9780762303878
Category : Science
Languages : en
Pages : 0

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Book Description
This volume brings together a set of reviews that provide a summary of our current knowledge of the proteolytic machinery and of the pathways of protein breakdown of prokaryotic and eukaryotic cells. Intracellular protein degradation is much more than just a mechanism for the removal of incorrectly folded or damaged proteins. Since many short-lived proteins have important regulatory functions, proteolysis makes a significant contribution to many cellular processes including cell cycle regulation and transciptional control. In addition, limited proteolytic cleavage can provide a rapid and efficient mechanism of enzyme activation or inactivation in eukaryotic cells. In the first chapter, Maurizi provides an introduction to intracellular protein degradation, describes the structure and functions of bacterial ATP-dependent proteases, and explores the relationship between chaperone functions and protein degradation. Many of the principles also apply to eukaryotic cells, although the proteases involved are often not the same. Interestingly, homologues of one of the bacterial proteases, Ion protease, have been found in mitochondria in yeast and mammals, and homologues of proteasomes, which are found in all eukaryotic cells (see below), have been discovered in some eubacteria. Studies of proteolysis in yeast have contributed greatly to the elucidation of both lysosomal (vacuolar) and nonlysosomal proteolytic pathways in eukaryotic cells. Thumm and Wolf (chapter 2) describe studies that have elucidated the functions of proteasomes in nonlysosomal proteolysis and the contributions of lysosomal proteases to intracellular protein breakdown. Proteins can be selected for degradation by a variety of differen mechanisms. The ubiquitin system is one complex and highly regulated mechanism by which eukaryotic proteins are targetted for degradation by proteosomes. In chapter 3, Wilkinson reviews the components and functions of the ubiquitin system and considers some of the known substrates for this pathway which include cell cycle and transcriptional regulators. The structure and functions of proteosomes and their regulatory components are described in the two subsequent chapters by Tanaka and Tanahashi and by Dubiel and Rechsteiner. Proteasomes were the first known example of threonine proteases. They are multisubunit complexes that, in addition to being responsible for the turnover of most short-lived nuclear and cytoplasmic protein, are also involved in antigen processing for presentation by the MHC class I pathway. Recent studies reviewed by McCracken and colleagues (chapter 6) lead to the exciting conclusion that some ER-associated proteins are degraded by cytosolic proteasomes. Lysosomes are responsible for the degradation of long-lived proteins and for the enhanced protein degradation observed under starvation conditions. In chapter 7 Knecht and colleagues review the lysosomal proteases and describe studies of the roles of lysosomes and the mechanisms for protein uptake into lysosomes. Methods of measuring the relative contribution of different proteolytic systems (e.g., ubiquitin-proteasome pathway, calcium-dependent proteases, lysosomes) to muscle protein degradation, and the conclusions from such studies, are reviewed by Attai and Taillinder in the following chapter. Finally, proteases play an important role in signaling apoptosis by catalyzing the limited cleavage of enzymes. Mason and Beyette review the role of the major players, caspases, which are both activated by and catalyze limite proteolysis, and also consider the involvement of other protoelytic enzymes in this pathway leading cell death.

Beyond the Molecular Frontier

Beyond the Molecular Frontier PDF Author: National Research Council
Publisher: National Academies Press
ISBN: 0309168392
Category : Science
Languages : en
Pages : 238

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Book Description
Chemistry and chemical engineering have changed significantly in the last decade. They have broadened their scopeâ€"into biology, nanotechnology, materials science, computation, and advanced methods of process systems engineering and controlâ€"so much that the programs in most chemistry and chemical engineering departments now barely resemble the classical notion of chemistry. Beyond the Molecular Frontier brings together research, discovery, and invention across the entire spectrum of the chemical sciencesâ€"from fundamental, molecular-level chemistry to large-scale chemical processing technology. This reflects the way the field has evolved, the synergy at universities between research and education in chemistry and chemical engineering, and the way chemists and chemical engineers work together in industry. The astonishing developments in science and engineering during the 20th century have made it possible to dream of new goals that might previously have been considered unthinkable. This book identifies the key opportunities and challenges for the chemical sciences, from basic research to societal needs and from terrorism defense to environmental protection, and it looks at the ways in which chemists and chemical engineers can work together to contribute to an improved future.

Functions and Mechanisms of Bacterial Protein Homeostasis and Stress Responses

Functions and Mechanisms of Bacterial Protein Homeostasis and Stress Responses PDF Author: Axel Mogk
Publisher: Frontiers Media SA
ISBN: 2889741931
Category : Science
Languages : en
Pages : 334

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Book Description
The Cover Image for This Research Topic is Used With Permission of the Authors and Publishers of the Following Article: Winkler J, Seybert A, König L, Pruggnaller S, Haselmann U, Sourjik V, Weiss M, Frangakis AS, Mogk A, Bukau B.EMBO J. 2010 Mar 3;29(5):910-23. doi: 10.1038/emboj.2009.412. Epub 2010 Jan 21

Adverse Effects of Cancer Chemotherapy: Anything New to Improve Tolerance and Reduce Sequelae?

Adverse Effects of Cancer Chemotherapy: Anything New to Improve Tolerance and Reduce Sequelae? PDF Author: Kulmira Nurgali
Publisher: Frontiers Media SA
ISBN: 2889454827
Category :
Languages : en
Pages : 245

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Book Description
Advances in anti-cancer chemotherapy over recent years have led to improved efficacy in curing or controlling many cancers. Some chemotherapy-related side-effects are well recognized and include: nausea, vomiting, bone marrow suppression, peripheral neuropathy, cardiac and skeletal muscle dysfunction and renal impairment. However, it is becoming clearer that some chemotherapy-related adverse effects may persist even in long term cancer survivors. Problems such as cognitive, cardiovascular and gastrointestinal dysfunction, and neuropathy may lead to substantial long term morbidity. Despite improvements in treatments to counteract acute chemotherapy-induced adverse effects, they are often incompletely effective. Furthermore, counter-measures for some acute side-effects and many potential longer term sequelae of anti-cancer chemotherapy have not been developed. Thus, new insights into prevalence and mechanisms of cancer chemotherapy-related side effects are needed and new approaches to improving tolerance and reduce sequelae of cancer chemotherapy are urgently needed. The present Research Topic focuses on adverse effects and sequelae of chemotherapy and strategies to counteract them.

Lasso Peptides

Lasso Peptides PDF Author: Yanyan Li
Publisher: Springer
ISBN: 1493910108
Category : Medical
Languages : en
Pages : 113

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Book Description
Lasso peptides form a growing family of fascinating ribosomally-synthesized and post-translationally modified peptides produced by bacteria. They contain 15 to 24 residues and share a unique interlocked topology that involves an N-terminal 7 to 9-residue macrolactam ring where the C-terminal tail is threaded and irreversibly trapped. The ring results from the condensation of the N-terminal amino group with a side-chain carboxylate of a glutamate at position 8 or 9, or an aspartate at position 7, 8 or 9. The trapping of the tail involves bulky amino acids located in the tail below and above the ring and/or disulfide bridges connecting the ring and the tail. Lasso peptides are subdivided into three subtypes depending on the absence (class II) or presence of one (class III) or two (class I) disulfide bridges. The lasso topology results in highly compact structures that give to lasso peptides an extraordinary stability towards both protease degradation and denaturing conditions. Lasso peptides are generally receptor antagonists, enzyme inhibitors and/or antibacterial or antiviral (anti-HIV) agents. The lasso scaffold and the associated biological activities shown by lasso peptides on different key targets make them promising molecules with high therapeutic potential. Their application in drug design has been exemplified by the development of an integrin antagonist based on a lasso peptide scaffold. The biosynthesis machinery of lasso peptides is therefore of high biotechnological interest, especially since such highly compact and stable structures have to date revealed inaccessible by peptide synthesis. Lasso peptides are produced from a linear precursor LasA, which undergoes a maturation process involving several steps, in particular cleavage of the leader peptide and cyclization. The post-translational modifications are ensured by a dedicated enzymatic machinery, which is composed of an ATP-dependent cysteine protease (LasB) and a lactam synthetase (LasC) that form an enzymatic complex called lasso synthetase. Microcin J25, produced by Escherichia coli AY25, is the archetype of lasso peptides and the most extensively studied. To date only around forty lasso peptides have been isolated, but genome mining approaches have revealed that they are widely distributed among Proteobacteria and Actinobacteria, particularly in Streptomyces, making available a rich resource of novel lasso peptides and enzyme machineries towards lasso topologies.

The Proteasome — Ubiquitin Protein Degradation Pathway

The Proteasome — Ubiquitin Protein Degradation Pathway PDF Author: Peter Zwickl
Publisher: Springer Science & Business Media
ISBN: 364259414X
Category : Science
Languages : en
Pages : 222

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Book Description
This volume gives an overview of pro tea some-mediated protein degradation and the regulatory role of the ubiquitin system in cellular proteolysis. The first chapter describes the molecular evolution of the proteasome and its associated activators, i. e. , the 20S core, the base and the lid of the 19S cap, and the 11 S regulator. The ensuing chapter gives an overview of the structure and assembly of the 20S proteasome and the regulation of the archaeal proteasome by PAN. The third contribution summarizes our knowledge on the eukaryotic 26S proteasome and its regulation by the 19S regu lator, followed by a chapter devoted to the llS regulator, which elucidates the structural basis for the 11 S-mediated activation of the 20S proteasome. The fifth chapter reviews in detail the role of the proteasome in the immune response. The subsequent chapter of the natural substrates of the gives a comprehensive description proteasome and their recognition by the enzymes of the ubiqui tination machinery. The penultimate chapter rounds up the in formation on intracellular distribution of proteasomes in yeast and mammalian cells, while the last contribution highlights proteasome inhibitors, tools which proved to be very valuable for dissecting the cellular roles of the proteasome and which might turn out to be of pharmacological importance.

Mitochondria and Anaerobic Energy Metabolism in Eukaryotes

Mitochondria and Anaerobic Energy Metabolism in Eukaryotes PDF Author: William F. Martin
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110612410
Category : Science
Languages : en
Pages : 269

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Book Description
Mitochondria are sometimes called the powerhouses of eukaryotic cells, because mitochondria are the site of ATP synthesis in the cell. ATP is the universal energy currency, it provides the power that runs all other life processes. Humans need oxygen to survive because of ATP synthesis in mitochondria. The sugars from our diet are converted to carbon dioxide in mitochondria in a process that requires oxygen. Just like a fire needs oxygen to burn, our mitochondria need oxygen to make ATP. From textbooks and popular literature one can easily get the impression that all mitochondria require oxygen. But that is not the case. There are many groups of organismsm known that make ATP in mitochondria without the help of oxygen. They have preserved biochemical relicts from the early evolution of eukaryotic cells, which took place during times in Earth history when there was hardly any oxygen avaiable, certainly not enough to breathe. How the anaerobic forms of mitochondria work, in which organisms they occur, and how the eukaryotic anaerobes that possess them fit into the larger picture of rising atmospheric oxygen during Earth history are the topic of this book.

Wine Fermentation

Wine Fermentation PDF Author: Harald Claus
Publisher: MDPI
ISBN: 3038976741
Category : Science
Languages : en
Pages : 176

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Book Description
Wineries are facing new challenges due to actual market demands for the creation of products exhibiting more particular flavors. In addition, climate change has lead to the requirement for grape varieties with specific features, such as convenient maturation times, enhanced tolerance towards dryness, osmotic stress, and resistance against plant-pathogens. The next generation of yeast starter cultures should produce wines with an appealing sensory profile and less alcohol. This Special Issue comprises actual studies addressing some of the problems and solutions for the environmental, technical, and consumer challenges of wine making today: Development of sophisticated mass spectroscopic methods enable the identification of the major metabolite spectrum of grapes/wine and deliver detailed insights in terroir and yeast-specific traits;Knowledge of the origin and reactions of reductive sulphur compounds facilitates the avoidance of unpleasant wine odors;Innovative physical–chemical treatments support effective and sustainable color extraction from red grape varieties;Enological enzymes from yeasts used directly or in the form of starter cultures are promising tools to increase the juice yields, color intensity, and aroma of wine;Natural and artificial Saccharomyces hybrids as well as collections of adapted wild isolates from various ecological niches will extend winemakers repertoire, allowing individual fermentations;Exact process control of wine fermentations by convenient computer programs will guarantee consistently high product quality.

Mineral Nutrition of Higher Plants

Mineral Nutrition of Higher Plants PDF Author: Horst Marschner
Publisher: Gulf Professional Publishing
ISBN: 9780124735439
Category : Language Arts & Disciplines
Languages : en
Pages : 920

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Book Description
This text presents the principles of mineral nutrition in the light of current advances. For this second edition more emphasis has been placed on root water relations and functions of micronutrients as well as external and internal factors on root growth and the root-soil interface.