Download or read book Analysis of the Role of DNA Helicase II uvrD in DNA Replication in Escherichia Coli written by Sandeep Bhat and published by . This book was released on 1996 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Purification and Characterization of the Escherichia Coli Helicase II Protein and a Study of the Protein s Enzymatic Activities written by Gregory Thomas Runyon and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study Protein protein Interaction in Methyl directed DNA Mismatch Repair in E Coli Exonuclease I Exo I and DNA Helicas II UvrD A Minimal Exonuclease Domain of WRN Forms a Hexamer on DNA and Possesses Both 3 5 Exonuclease and 5 Protruding Strand Endonuclease Activities Solving the Structure of the Ligand Binding Domain of the Pregnane Xenobiotic Receptor with 17 Estradiol and written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Exonuclease I (ExoI) from Escherichia coli is a monomeric enzyme that processively degrades single stranded DNA in the 3' to 5' direction and has been implicated in DNA recombination and repair. It functions in numerous genome maintenance pathways, with particularly well defined roles in methyl-directed mismatch repair (MMR). The Escherichia coli MMR pathway can be reconstituted in vitro with the activities of eight proteins (8). MutS, MutL and MutH are involved in initiation of repair including mismatch recognition and generation of a nick at a nearby GATC sequence (53, 54, 55, 56). The hemimethylated state of GATC sequences immediately following replication serves as a signal to direct repair to the nascent strand of the DNA duplex (57, 58). DNA helicase II and one of several exonucleases (Exonucleas I, Exonuclease VII and RecJ) are required to excise the error-containing DNA strand beginning at the nicked GATC site (34, 35). Restoration of the correct DNA sequence by repair synthesis involves DNA polymerase III holoenzyme and SSB, and the final nick is sealed by DNA ligase (34). To identify interactions with ExoI involved in MMR repair system, we used the yeast two-hybrid system with ExoI as bait. By screening an E.coli genomic library, E. coli DNA helicase II (UvrD) was identified as a potential interacting protein. UvrD has been shown to be required for DNA excision repair, methyl-directed mismatch repair and has some undefined, role in DNA replication and recombination. In this report, in vitro experiments confirm that UvrD and ExoI make a direct physical interaction that may be required for function of the methyl-directed mismatch repair. Werner Syndrome is a rare autosomal recessive disease characterized by a premature aging phenotype, genomic instability and a dramatically increased incidence of cancer and heart disease. Mutations in a single gene encoding a 1,432 amino-acid helicase/exonuclease (hWRN) have been shown to be responsible for the development o

Download or read book Interpretation of Ultraviolet stimulated DNA Replication in Escherichia Coli written by Priscilla Kensley Teichmann Cooper and published by . This book was released on 1971 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recombinational Repair of DNA Damage written by Andrei Kuzminov and published by Landes Bioscience. This book was released on 1996 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanism and Regulation of DNA Replication written by Alan Kolber and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1 - Chromosome Replication in Procaryotes.- Enzymatic Aspects of Chromosome Replication in E. coli.- Escherichia coli DNA Polymerase II and III.- Initiation of DNA Synthesis.- In vitro Replication of DNA.- The Role of ATP in Chromosome Replication Studied in Toluenized Escherichia coli.- Membrane Protein Components and DNA Synthesis in Escherichia coli.- A Possible Common Role for DNA Polymerase I and Exonuclease V in Escherichia coli.- The Joining of DNA Duplexes at Their Base-Paired Ends.- The Attachment of the Bacterial Chromosome to the Cell Membrane.- DNA Replication in Bacteriophage and.

Download or read book Genetic Analysis of Escherichia Coli DNA Helicase II written by Enxin Deng and published by . This book was released on 1999 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Escherichia Coli DNA Helicase II written by Mark Christopher Hall and published by . This book was released on 1998 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Biological Methods for Bacillus written by Colin R. Harwood and published by Wiley. This book was released on 1991-02-18 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular Biological Methods for Bacillus Edited by C. R. Harwood, Department of Microbiology, University of Newcastle upon Tyne, UK and S. M. Cutting, The Biological Laboratories, Harvard University, USA This volume represents the first major attempt to produce a compendium of the experimental methods used for the analysis of Bacillus, one of the most important procaryotic genera. Since the pioneering work on the transformation and genetic analysis of Bacillus subtilis by John Spizizen and his colleagues in the late 1950s this microorganism has been extensively studied and is now one of the best understood. More than forty of the world’s leading researchers in the field have generously contributed experimental procedures—devised and used in their laboratories—to this book. The aim throughout has been to present methods as simple step-by-step protocols which have been thoroughly tried and tested. The context in which the methods are used is discussed in detail and relevant information provided on the physiology and genetics of Bacillus. In addition valuable support is provided in the form of troubleshooting tips and advice on safety, the preparation of reagents, and the use of equipment. The book will be invaluable to those working with the genus Bacillus and related genera—both established researchers and those wishing to use this important microorganism for the first time.

Download or read book Genetic and Biochemical Analysis of Escherichia Coli DNA Helicase II written by Brian Keith Washburn and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Genetic and Biochemical Analysis of DNA Helicase II Mutants of Escherichia Coli written by Gang Zhang and published by . This book was released on 1997 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cellular Contexts and Biochemical Mechanisms of Dna Replication Restart in Escherichia Coli written by Aidan Mair McKenzie and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Before cells can divide, they must first duplicate their genome through DNA replication. DNA replication is facilitated by the coordinated activities of multiprotein complexes (replisomes). While the speed and abilities of replisomes are mystifying, they are frequently met with challenges to their progression. During active replication, Escherichia coli replisomes are estimated to physically dissociate from the genome at least once per cell cycle after colliding with DNA damage or tightly associated proteins. To sustain cellular viability, DNA replication needs to be reinitiated at these abandoned replication forks through the process of DNA replication restart. Here, I present a genetic, biochemical, and structural investigation of DNA replication restart in E. coli to better define its cellular role and mechanistic details. In Chapter 1, I outline the original discovery of replication restart proteins (RRPs) and the evidence used to propose a three-pathway model for DNA replication restart in E. coli (consisting of the PriA/PriB, PriA/PriC, and PriC/Rep pathways). To facilitate replication restart, each pathway recognizes an abandoned replication fork, remodels the fork, recruits additional RRPs, and ultimately reloads the replicative helicase (DnaB) onto the DNA with the help of its helicase loader (DnaC). Chapter 2 describes a genetic study that systematically defined the roles of specific replication restart pathways in a variety of cellular environments. My results helped integrate DNA replication restart within other cellular processes by revealing a tight link between the repair of double-strand breaks and the PriA/PriB restart pathway. In Chapter 3, I exploited a streamlined DnaB reloading system afforded by PriC to structurally define its manner of binding to the replicative helicase/loader (DnaB6/DnaC6) complex. The cryoEM structure identified dramatic conformational changes required to satisfy the binding interface between PriC and DnaB, and subsequent biochemical investigation identified a hydrophobic packing interface as important for sustained binding. A summary of the findings in Chapters 2 and 3, as well as future directions, are provided in Chapter 4. This work probed mechanistic details of DNA replication restart in E. coli by revealing the cellular processes (and missteps) that necessitate replication restart and helped define the biochemical mechanism of PriC-mediated replicative helicase loading.

Download or read book DNA Helicases and DNA Motor Proteins written by Maria Spies and published by Springer Science & Business Media. This book was released on 2012-11-19 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, a number of groundbreaking structural and mechanistic studies deepened our understanding of helicase mechanisms and established new approaches for their analyses. Many fundamental mechanistic questions ranging from the mechanism of force generation, mechanochemical coupling to distinct mechanisms by which the same enzyme translocates on DNA removing obstacles, unwinds DNA and/or remodels nucleoprotein complexes, however, remain to be answered. It is even less understood how the helicase motors are incorporated into a wide range of genome maintenance and repair machines. The field has reached a stage when the studies of molecular mechanisms and basic biology of helicases can and shall be integrated with the studies of development, cancer and longevity. The objective of this book is to provide the first systematic overview of structure, function and regulation of DNA helicases and related molecular motors. By integrating the knowledge obtained through the diverse technical approaches ranging from single-molecule biophysics to cellular and molecular biological studies the editors aim to provide a unified view on how helicases function in the cell, are regulated in response to different cellular stresses and are integrated into large macromolecular assemblies to form a complex and adaptive living system.

Download or read book The Role of Nucleotide Excision Repair in Restoring Replication Following UV induced Damage in Escherichia Coli written by Kelley Nicole Newton and published by . This book was released on 2012 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following low levels of UV exposure, Escherichia coli cells deficient in nucleotide excision repair recover and synthesize DNA at near wild type levels, an observation that formed the basis of the post replication recombination repair model. In this study, we characterized the DNA synthesis that occurs following UV-irradiation in the absence of nucleotide excision repair and show that although this synthesis resumes at near wild type levels, it is coincident with a high degree of cell death. We confirm that the replication occurring under these conditions involves extensive levels of strand exchange. However, cells undergoing this form of replication accumulate strand exchange intermediates that fail to resolve into discrete molecules, resulting in grossly filamentous, multinucleate cells. Taken together the results demonstrate that the DNA synthesis that occurs in UV-irradiated nucleotide excision repair mutants is aberrant and suggests that post replication repair is not an efficient mechanism to promote survival in the absence of nucleotide excision repair. The role that nucleotide excision repair plays in the recovery of replication following UV-induced DNA damage was further characterized by examining the specific role of UvrD in processing and restoring UV-arrested replication forks. UvrD is a helicase with functions associated with nucleotide excision repair and replication. UvrD catalyzes the removal of the damaged region by nucleotide excision repair proteins and removes the stretch of DNA incised during methyl-directed mismatch repair during replication. Recent biochemical studies have led to the proposal that UvrD may promote fork regression and facilitate resetting of the replication fork following arrest. However, the molecular activity of UvrD at replication forks in vivo has not been directly examined. In this study, we show that UvrD is required for DNA synthesis to recover. However, in the absence of UvrD, the displacement and partial degradation of the nascent DNA at the arrested fork occurs normally. In addition, damage-induced replication intermediates persist and accumulate in uvrD mutants in a manner that is similar to that observed in other nucleotide excision repair mutants. These data indicate that following arrest by DNA damage, UvrD is not required to catalyze fork regression in vivo and suggest that the failure of uvrD mutants to restore DNA synthesis following UV-induced arrest relates to its role in nucleotide excision repair.

Download or read book Genetic and Biochemical Evidence for the Involvement of Escherichia Coli DNA Polymerase II in DNA Replication and Repair written by Savithri Rangarajan and published by . This book was released on 1999 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Kinetic Characterizations of DNA Replication Fidelity of E Coli DNA Polymerase II written by Zhijie Wang and published by . This book was released on 1998 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Elucidating the Role of the Escherichia Coli RarA Protein at the Interface of DNA Replication and DNA Repair written by Tyler H. Stanage and published by . This book was released on 2017 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: In each cell cycle, the replisome encounters replication blocks that include DNA lesions, tightly bound DNA-protein complexes, and breaks in the DNA. In Escherichia coli, many pathways have evolved to recognize, respond to, and repair these replication blocks so that replication can be completed in a timely and accurate manner. The highly conserved RarA (Replication associated recombination protein A) protein family has been implicated in the faithful resolution of these replication conflicts. Despite high conservation and extensive work conducted on this protein family, the overall function of RarA remains enigmatic. Here, we carefully describe two novel DNA-dependent functions for the E. coli RarA protein. First, we demonstrated that RarA binds to and hydrolyzes ATP at double-stranded DNA ends in order to generate single-stranded DNA flaps. Second, using a single-molecule reconstituted DNA replication assay, we show that RarA generated single-stranded DNA gaps behind active replisomes in an ATP-dependent manner. This activity is achieved by RarA disengaging DNA polymerase III cores from their [beta]2 processivity clamps. In vivo, we demonstrate that RarA--presumably using its gap creation activity--generates suitable substrates for post-replication repair pathways including RecFOR-mediated homologous recombination and translesion DNA synthesis. Loss of this function results in impaired growth and varied DNA replication phenotypes. Overexpression of rarA is toxic due to its ATPase activity and the resulting overuse of mutagenic TLS polymerases. Together, these results further elucidate the role of the RarA protein family at the interface of DNA replication and DNA repair.