Abstract

Essentials of Glycobiology

(A. Varki, R. Cummings, J. Esko, H. Freeze, G. Hart, and J. Marth (eds.) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 1999, 653 p., $95)

Glycobiology has advanced significantly during the past two decades. These achievements are due to deciphering of the structures of a number of glycoconjugates, which are the most complex class of biopolymers, and to discoveries of new types of plant and animal lectins specific to certain carbohydrate determinants as well as to characterization of new enzymes involved in biosynthesis and decomposition of carbohydrate-containing biopolymers. Extensive application of the methods of molecular biology to glycobiology enabled the deciphering of genetic mechanisms of a number of human diseases including lysosomal accumulation disorders. The reviewed book is an excellent introduction to modern glycobiology; it includes five sections totaling 41 chapters. The first section includes 5 chapters and considers the history of development of glycobiology, characteristics of carbohydrate moieties of glycoconjugates, their biological role, and their application in biology and medicine. The next and the largest section is entitled “Biosynthesis, metabolism, and function” and includes 16 chapters. Separate chapters consider metabolism of monosaccharides, biosynthesis of N- and O-glycans, and glycosylation of glycolipids, proteoglycans, and other classes of glycans synthesized in the Golgi apparatus. Special chapters describe data on glycosylation reactions in the nucleus and cytoplasm, degradation of glycoconjugates, and their fate in the body. Important terminal components of glycoconjugates (sialic acids) are characterized and the structure of bacterial polysaccharides and glycoproteins is described. Glycobiology has advanced significantly during the past two decades. These achievements are due to deciphering of the structures of a number of glycoconjugates, which are the most complex class of biopolymers, and to discoveries of new types of plant and animal lectins specific to certain carbohydrate determinants as well as to characterization of new enzymes involved in biosynthesis and decomposition of carbohydrate-containing biopolymers. Extensive application of the methods of molecular biology to glycobiology enabled the deciphering of genetic mechanisms of a number of human diseases including lysosomal accumulation disorders. The reviewed book is an excellent introduction to modern glycobiology; it includes five sections totaling 41 chapters. The first section includes 5 chapters and considers the history of development of glycobiology, characteristics of carbohydrate moieties of glycoconjugates, their biological role, and their application in biology and medicine. The next and the largest section is entitled “Biosynthesis, metabolism, and function” and includes 16 chapters. Separate chapters consider metabolism of monosaccharides, biosynthesis of N- and O-glycans, and glycosylation of glycolipids, proteoglycans, and other classes of glycans synthesized in the Golgi apparatus. Special chapters describe data on glycosylation reactions in the nucleus and cytoplasm, degradation of glycoconjugates, and their fate in the body. Important terminal components of glycoconjugates (sialic acids) are characterized and the structure of bacterial polysaccharides and glycoproteins is described.

A special section (chapters 22-30) considers lectins. The first chapter of this section describes animal lectins. The history of the discovery of this lectin group is considered as well as their modern classification, biosynthesis, movement, and specific binding to various carbohydrate determinants in intracellular compartments and on the surface of cells and organs.

Mannose-specific lectins (receptors) are one of the most extensively studied classes of lectins; they are responsible for the movement of lysosomal enzymes during their biogenesis and secretion. The I- and C-types of lectins are characterized in chapters 24-25. The first type (I-lectins) comprises the group of carbohydrate-binding proteins of the immunoglobulin family. Some of these lectins bind various sialic carbohydrate determinants and are known in the literature as Siglecs lectins. Another, smaller part of this lectin group (non-Siglecs) is localized on the surface of platelets, endothelium, and activated B cells binding non-sialic glycoconjugates that are predominantly proteoglycans. The second type of animal lectins (C-lectins; chapter 26) comprises the large group of Ca²⁺-dependent lectins including colectins and selectins, which are abundant in humans and animals.

Lectins binding beta-galactosyl-containing glycoconjugates were designated galectins (chapter 27). Most of these lectins are soluble and secreted proteins. Certain galectins enhance intercellular adhesion, while others can induce programmed cell death (apoptosis) or on the contrary can activate mitosis. Chapter 28 characterizes microbial carbohydrate-binding proteins (adhesins), which recognize and bind the carbohydrate ligands on the surface of the animal cells. Thus, adhesins are involved in the initial binding stages of microorganisms and viruses infecting the host cells. The proteins specifically binding glycosaminoglycans and plant lectins are considered in chapters 29 and 30, respectively. The next section (chapters 31-37) describes genetic lesions and diseases developing due to altered glycosylation of carbohydrate-containing compounds. Unfortunately, a large group of hereditary disorders of decomposition of carbohydrate-containing compounds (lysosomal accumulation disorders) is not considered in the book.

The final section (chapters 38-41) describes the modern methods of glycobiology. Structural analysis of glycoconjugates, general principles and methods in chemical and enzymatic synthesis of glycan structures, and natural and synthetic glycosylation inhibitors are considered. A special chapter describes the role of glycobiology in biotechnology and medicine.

A dictionary of terms used in the text and a subject index are at the end of the book. Each chapter contains a short list of references. The book also includes a list of fundamental monographs dealing with various aspects of glycobiology.

In general, the book is valuable not only for experts in glycobiology but also for many biochemists, molecular biologists, biotechnologists, and physicians.

G. Ya. Wiederschain