Glycans are saccharides that can be attached to a wide variety of biological molecules through an enzymatic process called glycosylation to augment their function. Of the four fundamental building blocks of life, proteins, carbohydrates (glycans), lipids and nucleic acids, glycans have received the least attention from researchers. Glycans are found in archaea, bacteria and eukaryotes, and their diverse functions contribute to physical and structural integrity, extracellular matrix formation, signal transduction, protein folding and information exchange between cells (and pathogens). Glycans are the predominant molecule on the cell surface and serve as the first point of contact between a cell and other cells, the extracellular matrix and pathogens. The heightened evolutionary pressure of being at the front lines of cellular collaboration and conflict most likely led to the diversification of glycans. Glyco-epitope diversity enhances the role of glycans in the group of debilitating and life-shortening disorders known as congenital muscular dystrophy, or CMD. Both membrane proteins and the ECM are highly glycosylated, and O-glycans are essential for proper ECM function and communication between cells and the ECM. Several Glycoepitomics forms of CMD are known to result from dysfunctional O-glycosylation of membrane and ECM proteins; however, one-third of CMDs arise from an unknown genetic etiology. Glycosylation is a critical function of the biosynthetic-secretory pathway in the endoplasmic reticulum (ER) and Golgi apparatus. Glycosylation increases the diversity of the proteome to a level unmatched by any other post-translational modification. Glycosidases catalyze the hydrolysis of glycosidic bonds to remove sugars from proteins. These enzymes are critical for glycan processing in the ER and Golgi, and each enzyme shows specificity for removing a particular sugar (e.g., mannosidase).

Glycans can mediate a wide variety of biological roles by virtue of their mass, shape, charge, or other physical properties. However, many of their more specific biological roles are mediated via recognition by GBPs. Nature appears to have taken full advantage of the vast diversity of glycans expressed in organisms by evolving protein modules to recognize discrete glycans that mediate specific physiological or pathological processes. Excluding glycan-specific antibodies, GBPs broadly into two major groups such as lectins and glycosaminoglycan-binding proteins. Most lectins are members of families with defined “carbohydrate-recognition domains” (CRDs) that apparently evolved from shared ancestral genes, often retaining specific features of primary amino acid sequence or three-dimensional structure. Thus, new family members can be identified by searching protein sequence or structural databases. The natural ligands for most lectins are typically complex glycoconjugates that carry clustered arrays of the cognate carbohydrate or unique glycan structures, thus cooperating with clustered lectin-binding sites to generate high-avidity binding, which is further enhanced by mass transport effects (high local concentrations of ligands). Paulson group investigates the roles of glycan binding proteins that mediate cellular processes central to immune regulation and human disease. Their work includes at the interface of biology and chemistry to understand how the interaction of glycan binding proteins with their ligands mediates cell-cell interactions, endocytosis and cell signaling. Their multi-disciplinary approach is complemented by a diverse group of chemists, biochemists, cell biologists, and molecular biologists.

The human gut hosts trillions of bacteria that directly influence human health. The majority of gut microbiota play an important role in nutrition by metabolizing host-indigestible complex glycans into short-chain fatty acids. Growth of the mesh-like peptidoglycan (PG) sacculus located between the bacterial inner and outer membranes (OM) is tightly regulated to ensure cellular integrity, maintain cell shape, and orchestrate division. Cytoskeletal elements direct placement and activity of PG synthases from inside the cell, but precise spatiotemporal control over this process is poorly understood. Glycan catabolism contains metabolic pathway maps for glycans. Some of them contain an alternative representation of glycan biosynthesis or degradation, called the glycan structure map. Asparagine (N)-linked protein glycosylation is a ubiquitous co- and post-translational modification which can alter the biological function of proteins and consequently affects the development, growth, and physiology of organisms. In mammals, complex N-glycans are involved in different cellular processes including molecular recognition and signaling events.

The beginning of the 20(th) century marked the dawn of modern medicine with glycan-based therapies at the forefront. However, glycans quickly became overshadowed as DNA- and protein-focused treatments became readily accessible. The recent development of new tools and techniques to study and produce structurally defined carbohydrates has spurred renewed interest in the therapeutic applications of glycans. Essentials of glycobiology review focuses on advances within the past decade that are bringing glycan-based treatments back to the forefront of medicine and the technologies that are driving these efforts. These include the use of glycans themselves as therapeutic molecules as well as engineering protein and cell surface glycans to suit clinical applications to that of databases providing glycoenzyme data. Glycan therapeutics offer a rich and promising frontier for developments in the academic, biopharmaceutical, and medical fields. Martin Dalziel and their colleagues at Oxford University learned about glycans in the context of pathogen invasion, cancer and autoimmunity, and congenital diseases. Biota, GlaxoSmithKline, Gilead and Roche are the companies mainly focusing research on glycans section of diseases and its therapeutic applications. The Company’s ultimate goal is to bring to market promising novel classes of therapeutic agents, functional foods, and diagnostics based on the naturally occurring bioactive glycans.

Glycomics the scientific attempt to characterize and study carbohydrates, is a rapidly emerging branch of science, for which informatics is just beginning. Glycomics requires sophisticated algorithmic approaches. Several algorithms and models have been developed for glycobiology research in the past several years. The development and use of informatics tools and databases for glycobiology and glycomics research has increased considerably in recent years. However, the general development in this field can still be considered as being in its infancy when compared to the genomics and proteomics areas. In terms of bioinformatics in glycobiology, there are several paths of research that are currently in progress. The development of algorithms and software tools for interpretation of glycans to reliably support the characterization of glycan structures for high-throughput applications is the most immediate demand of the glycomics community. The global glycomics market was valued at $512.38 million in 2014 and poised to grow at a CAGR of 12.62% between 2012 and 2019, to reach $928.11 million in 2019. The rapid increase in research and development expenditure by pharmaceutical and biotech companies, and increased funding in proteomics and glycobiology research will be the two most important growth drivers for this market in the forecast period (2012–2019).

Glycobiology and Glycochemistry are the two main intertwined areas of Glycosciences, dealing with various aspects of glycans, including carbohydrate structure, biochemistry, biological functions and applications. This is necessary in order to sustain and advance the identification of key glycobiological aspects and the application of glycans and glycoengineering strategies in the design of novel therapies to improve human health. The glycans (carbohydrates) form a diverse group of biomolecules which play active parts in most physiological processes. The field of structural glycobiology concerns the structures of the glycans themselves, the proteins which interact with them and the nature of the interactions between the two. Drug targeting is important for our understanding of human health and disease, and for development of new therapeutic strategies. Researchers at the University of Georgia have received a five-year, $10.4 million grant from the National Institutes of Health to support the National Center for Biomedical Glycomics, a consortium of UGA faculty and staff working to develop new technologies for the analysis of glycans, Scientists now recognize that glycans play critical roles in cell regulation, human health and disease progression. The experts at the Complex Carbohydrate Research Center have experience and knowledge that make us a world leader in this field, and are creating technologies and tools that are the foundation for the next generation of diagnostics and treatments.

Carbohydrates were prominent in the early history of immunology in defining the identity of antigens recognized by antibodies. In addition, the ability of antibodies to specifically recognize glycans was exploited in studies defining the size of the antigen-binding site. Nevertheless, for many decades following these early discoveries the broader potential importance of carbohydrates in both innate and adaptive immune responses was largely overlooked. However, times are changing and glycobiologists and immunologists are now collaborating extensively to explore this very fertile area of immunobiology. Numerous carbohydrate-binding proteins, or lectins, have been identified on the surfaces of immune cells. Interactions of lectins with glycans usually require several monosaccharide moieties presented in the correct conformation for high-affinity binding. Modification of proteins and lipids by glycosylation is a highly regulated process resulting in a diverse repertoire of glycan structures. Glycans are at the center of many disorders and diseases sparking the possibility of exploiting them for therapeutic and diagnostic purposes. There are many biochemical pathways and diseases in which glycans are intricately involved. Gaging the vast potential and the promise that glycobiology holds, many pharma and biotech companies have already started allocating their R&D budget to it. Presently, with our drug arsenal fast depleting against drug resistant and mutant pathogens, glycobiology hold an untapped source of new candidate drugs. Carbohydrates were prominent in the early history of immunology in defining the identity of antigens recognized by antibodies. In addition, the ability of antibodies to specifically recognize glycans was exploited in studies defining the size of the antigen-binding site. Nevertheless, for many decades following these early discoveries the broader potential importance of carbohydrates in both innate and adaptive immune responses was largely overlooked. However, times are changing and glycobiologists and immunologists are now collaborating extensively to explore this very fertile area of immunobiology. Numerous carbohydrate-binding proteins, or lectins, have been identified on the surfaces of immune cells. Interactions of lectins with glycans usually require several monosaccharide moieties presented in the correct conformation for high-affinity binding. Modification of proteins and lipids by glycosylation is a highly regulated process resulting in a diverse repertoire of glycan structures. Glycans are at the center of many disorders and diseases sparking the possibility of exploiting them for therapeutic and diagnostic purposes. There are many biochemical pathways and diseases in which glycans are intricately involved. Gaging the vast potential and the promise that glycobiology holds, many pharma and biotech companies have already started allocating their R&D budget to it. Presently, with our drug arsenal fast depleting against drug resistant and mutant pathogens, glycobiology hold an untapped source of new candidate drugs.