This book spans diverse aspects of modified nucleic acids, from chemical synthesis and spectroscopy to in vivo applications, and highlights studies on chemical modifications of the backbone and nucleobases. Topics discussed include fluorescent pyrimidine and purine analogs, enzymatic approaches to the preparation of modified nucleic acids, emission and electron paramagnetic resonance (EPR) spectroscopy for studying nucleic acid structure and dynamics, non-covalent binding of low- and high-MW ligands to nucleic acids and the design of unnatural base pairs. This unique book addresses new developments and is designed for graduate level and professional research purposes.

This volume is a timely and comprehensive description of the many facets of DNA and RNA modification-editing processes and to some extent repair mechanisms. Each chapter offers fundamental principles as well as up to date information on recent advances in the field (up to end 2008). They ended by a shortconclusion and future prospect' section and

Conteudo: v.2 - RNA enzymes.

Naturally occurring RNA always contains numerous biochemically altered nucleotides. They are formed by enzymatic modification of the primary transcripts during the complex RNA maturation process designated RNA modification. A large number of enzymes catalyzing the formation of these modified nucleosides or converting one canonical base into another at the posttranscriptional level have been studied for many years, but only recently have systematic and comparative studies begun. The functions of individual enzymes and/or the modified/edited nucleosides in RNA, however, have remained largely ignored. This book provides advance information on RNA modification, including the associated editing machinery, while offering the reader some perspective on the significance of such modifications in fine-tuning the structure and functions of mature RNA molecules and hence the ability to influence the efficiency and accuracy of genetic expression. Outstanding scientists who are actively working on RNA modification/editing processes have provided up-to-date information on these intriguing cellular processes that have been generated over the course of millions of years in all living organisms. Each review has been written and illustrated for a large audience of readers, not only specialists in the field, but also for advanced students or researchers who want to learn more about recent progress in RNA modification and editing.

Directed evolution comprises two distinct steps that are typically applied in an iterative fashion: (1) generating molecular diversity and (2) finding among the ensemble of mutant sequences those proteins that perform the desired fu- tion according to the specified criteria. In many ways, the second step is the most challenging. No matter how cleverly designed or diverse the starting library, without an effective screening strategy the ability to isolate useful clones is severely diminished. The best screens are (1) high throughput, to increase the likelihood that useful clones will be found; (2) sufficiently sen- tive (i. e. , good signal to noise) to allow the isolation of lower activity clones early in evolution; (3) sufficiently reproducible to allow one to find small improvements; (4) robust, which means that the signal afforded by active clones is not dependent on difficult-to-control environmental variables; and, most importantly, (5) sensitive to the desired function. Regarding this last point, almost anyone who has attempted a directed evolution experiment has learned firsthand the truth of the dictum “you get what you screen for. ” The protocols in Directed Enzyme Evolution describe a series of detailed p- cedures of proven utility for directed evolution purposes. The volume begins with several selection strategies for enzyme evolution and continues with assay methods that can be used to screen enzyme libraries. Genetic selections offer the advantage that functional proteins can be isolated from very large libraries s- ply by growing a population of cells under selective conditions.

A review of innovative tools for creative nucleic acid chemists that open the door to novel probes and therapeutic agents Nucleic acids continue to gain importance as novel diagnostic and therapeutic agents. With contributions from noted scientists and scholars, Enzymatic and Chemical Synthesis of Nucleic Acid Derivatives is a practical reference that includes a wide range of approaches for the synthesis of designer nucleic acids and their derivatives. The book covers enzymatic (including chemo-enzymatic) methods, with a focus on the synthesis and incorporation of modified nucleosides. The authors also offer a review of innovative approaches for the non-enzymatic chemical synthesis of nucleic acids and their analogs and derivatives, highlighting especially challenging species. The book offers a concise review of the methods that prepare novel and heavily modified polynucleotides in sufficient amount and purity for most clinical and research applications. This important book: -Presents a timely and topical guide to the synthesis of designer nucleic acids and their derivatives -Addresses the growing market for nucleotide-derived pharmaceuticals used as anti-infectives and chemotherapeutic agents, as well as fungicides and other agrochemicals. -Covers novel methods and the most recent trends in the field -Contains contributions from an international panel of noted scientistics Written for biochemists, medicinal chemists, natural products chemists, organic chemists, and biotechnologists, Enzymatic and Chemical Synthesis of Nucleic Acid Derivatives is a practice-oriented guide that reviews innovative methods for the enzymatic as well as non-enzymatic synthesis of nucleic acid species.