Two decades of research on the signaling capacity of hydrogen sulfide (H2S) in biological systems has led to parallel investigations of other reactive sulfur species (RSS) such as persulfides (RSSH) and polysulfides (RSS[subscript n]R, n>1). The purpose of this dissertation was to develop and assess new investigative tools that selectively detect or effectively deliver RSS under biologically relevant conditions. These chemical tools are of significant interest to the redox and molecular signaling communities and can be used to further define the prevalence, signaling capacity, and therapeutic effects of RSS, representing a significant advancement within the field. In chapter II, we describe the design, synthesis, and examination of an innovative, reaction-based fluorescent probe that exploits the double nucleophilic character of H2S by undergoing an intramolecular cyclization to release a fluorescent reporter. Specifically, we employed a highly unique selenosulfide moiety as a trigger for H2S detection. Given the distinct chemical differences between selenium and sulfur, we reasoned that the selenium half would provide access to chemical probes with high reactivity towards and selectively for H2S. Meanwhile, a suitable handle for improving the physicochemical properties of the probe, including its water solubility, cell permeability, and tissue specificity, could be supplied by the sulfide half. Using this novel design strategy, we successfully produced and assessed two H2S-selective probes: AL1, which displayed good water solubility, cell permeability, and overall biocompatibility, and AL2, which displayed cancer cell specificity. Concomitant to detection, chapter III discusses the synthesis and application of a self-reporting donor (ZL47), sensitive to reactive oxygen species (ROS). To accomplish this, we appended an aryl boronate ester to 7-hydroxycoumarin via an S-alkyl thiocarbonate linker allowing for the simultaneous release of COS, an H2S precursor, and a fluorescent reporter in response to hydrogen peroxide. In addition, we determined that ZL47 was a useful bifunctional tool with an ability to both image and alleviate oxidative stress in live cells, highlighting its potential as a theranostic. Chapter IV describes a novel ROS-activated persulfide donor (RAH393) that operates through a unique mechanistic pathway that avoids the production of a 1,4-quinone methide as a toxic byproduct, a major setback for ZL47 and related donors that employ a 1,6-elimination. In addition to confirming that its lactone byproduct was nontoxic, we were able to demonstrate the impressive cellular protection provided by RAH393 against high concentrations of ROS in live HeLa cells. Because this donor proved to be a valuable tool for generating persulfides in response to ROS, in chapter V, we investigated the therapeutic effects of an analogue that targets mitochondria (Mito-PD), the primary producers of ROS and a known site of RSS oxidation. To accomplish this, the mixed disulfide of RAH393 was modified and equipped with a lipophilic cation to facilitate mitochondrion uptake. Using confocal laser microscopy, we confirmed Mito-PD’s preferential release of persulfides within mitochondria from co-localization studies using AL1 (an H2S-selctive probe) and Mitotracker Red. In addition, we demonstrated that Mito-PD protects cardiomyoblast cells in culture (H9C2) from doxorubicin (DOX)-induced cardiotoxicity. Subsequent studies with JC-1, a fluorescent probe that reports on mitochondrial membrane potential, indicate that Mito-PD effectively preserves the membrane potential of DOX treated cells, increasing their viability. These initial studies highlight the therapeutic benefits of mitochondria-targeting RSS donors and their potential for mitigating DOX-induced cardiotoxicity.

Hydrogen sulfide (H2S) is a naturally occurring signaling molecule produced in vivo and plays a pivotal role in regulating a wide array of physiological processes. Additionally, emerging findings have illuminated that many of the biological effects initially attributed to H2S may actually stem from other reactive sulfur species (RSS), including hydropersulfides (RSSH) and various higher-order polysulfur species (RSSnH, RSSnR, and HSnH, where n > 1). These studies have underscored the contributions of these species to essential cellular processes, such as the efficient scavenging of reactive oxygen species and electrophiles, and their influence on mitochondrial function. Nonetheless, the chemistry of RSS remains challenging due to their inherently reactive nature, and their precise measurement within biological systems continues to pose a formidable challenge. This compilation of reprints focuses on recent advancements in the field of H2S/RSS chemical biology. It encompasses original research studies and comprehensive reviews, all geared towards exploring the therapeutic potential of H2S/RSS donors in the treatment of various conditions, including cancer, neurological disorders, and cardiovascular disease. Furthermore, it delves into the molecular mechanisms and physiological roles played by RSS along with the development of methodologies for quantifying and measuring the distribution of RSS within biological systems.

Since 1988, there has been much literature published on the chemistry of nitric oxide, particularly in the field of S-nitrosation and the chemistry of S-nitroso compounds. Written by a chemist for the chemistry community, this book provides an update of the chemistry of nitrosation reactions, dealing with both the synthetic and mechanistic aspects of these reactions. It also looks at the chemistry of nitric oxide in relation to the amazing biological properties of this simple diatomic molecule, which were unknown until around 1990.* Provides an update on previously published literature on nitric oxide chemistry* Contains chapters on reagents for nitrosation, nitrosation at nitrogen, aliphatic and aromatic carbon, oxygen, sulfur and metal centres* Looks at hot research topics such as synthesis, properties and reactions of s-nitrosothiols

This book provides a comprehensive overview of Expressed Protein Ligation (EPL), detailing methods and protocols to generate site-specifically modified proteins. Chapters include an overview of the protein semi-synthesis field, as well as related areas that have contributed to the development of EPL such as protein splicing and peptide synthesis. Following the introductory chapters, the rest of the book guides readers through protocols to perform EPL reactions, methods to synthesize peptide thioesters and to perform peptide and protein ligations, label proteins inside living cells, protocols for the semi-synthesis of phorphorylated, glycosylated and ubiquitylated proteins, synthesis and assembly of assymetrically modified nucleosomes, use of ligation auxiliaries and synthesis of cyclic proteins, as well as novel desulfurization strategies and use of selective Cys side chain protection to obtain precisely modified proteins.Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Expressed Protein Ligation: Methods and Protocols will ensure successful implementation of protein semi-synthesis methods to further study the structure and function of proteins.

Presents a multidisciplinary analysis of the integration among reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive sulfur species (RSS). Since plants are the main source of our food, the improvement of their productivity is the most important task for plant biologists. In this book, leading experts accumulate the recent development in the research on oxidative stress and approaches to enhance antioxidant defense system in crop plants. They discuss both the plant responses to oxidative stress and mechanisms of abiotic stress tolerance, and cover all of the recent approaches towards understanding oxidative stress in plants, providing comprehensive information about the topics. It also discusses how reactive nitrogen species and reactive sulfur species regulate plant physiology and plant tolerance to environmental stresses. Reactive Oxygen, Nitrogen and Sulfur Species in Plants: Production, Metabolism, Signaling and Defense Mechanisms covers everything readers need to know in four comprehensive sections. It starts by looking at reactive oxygen species metabolism and antioxidant defense. Next, it covers reactive nitrogen species metabolism and signaling before going on to reactive sulfur species metabolism and signaling. The book finishes with a section that looks at crosstalk among reactive oxygen, nitrogen, and sulfur species based on current research done by experts. Presents the newest method for understanding oxidative stress in plants. Covers both the plant responses to oxidative stress and mechanisms of abiotic stress tolerance Details the integration among reactive oxygen species (ROS), reactive nitrogen species (RNS) and reactive sulfur species (RSS) Written by 140 experts in the field of plant stress physiology, crop improvement, and genetic engineering Providing a comprehensive collection of up-to-date knowledge spanning from biosynthesis and metabolism to signaling pathways implicated in the involvement of RONSS to plant defense mechanisms, Reactive Oxygen, Nitrogen and Sulfur Species in Plants: Production, Metabolism, Signaling and Defense Mechanisms is an excellent book for plant breeders, molecular biologists, and plant physiologists, as well as a guide for students in the field of Plant Science.

Scientists have long sought to unravel the fundamental mysteries of the land, life, water, and air that surround us. But as the consequences of humanity's impact on the planet become increasingly evident, governments are realizing the critical importance of understanding these environmental systemsâ€"and investing billions of dollars in research to do so. To identify high-priority environmental science projects, Grand Challenges in Environmental Sciences explores the most important areas of research for the next generation. The book's goal is not to list the world's biggest environmental problems. Rather it is to determine areas of opportunity thatâ€"with a concerted investmentâ€"could yield significant new findings. Nominations for environmental science's "grand" challenges were solicited from thousands of scientists worldwide. Based on their responses, eight major areas of focus were identifiedâ€"areas that offer the potential for a major scientific breakthrough of practical importance to humankind, and that are feasible if given major new funding. The book further pinpoints four areas for immediate action and investment.

Chemical Tools for Imaging, Manipulating, and Tracking Biological Systems: Diverse Methods for Optical Imaging and Conjugation, Volume 639, the latest release in the Methods in Enzymology series, continues the legacy of this premier serial with quality chapters authored by leaders in the field. Chapters in this new release include Fluorogenic detection of protein aggregates in live cells using the AggTag method, Synthesis and Application of Ratiometric Probes for Hydrogen Peroxide Detection, Chemical Tools for Multicolor Protein FRET with Tryptophan, Fluorescing Isofunctional Ribonucleosides for Adenosine Deaminase Activity and Inhibition, Temporal profiling establishes a dynamic S-palmitoylation cycle, Solvation-guided design of fluorescent probes for discrimination of amyloids, and much more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Methods in Enzymology series Includes the latest information on retinoid signaling pathways

This Special Issue is a collection of research articles focused on the production and role of nitric oxide in plants. Nitric oxide is a crucial molecule used in the orchestration of cellular events in animals and plants. With a mixture of primary research papers and review articles written by some of the top researchers in the field, this work encompasses many aspects of this important and growing area of biochemistry.

This volume provides a collection of contemporary perspectives on using activity-based protein profiling (ABPP) for biological discoveries in protein science, microbiology, and immunology. A common theme throughout is the special utility of ABPP to interrogate protein function and small-molecule interactions on a global scale in native biological systems. Each chapter showcases distinct advantages of ABPP applied to diverse protein classes and biological systems. As such, the book offers readers valuable insights into the basic principles of ABPP technology and how to apply this approach to biological questions ranging from the study of post-translational modifications to targeting bacterial effectors in host-pathogen interactions.