**Author details**

300 The Complex World of Polysaccharides

chains in this case.

information flows.

HA fragments form stable bonds with NA.

requires a complex of about 300 N-acetylglucosaminylatransferases and glucuronyltransferases occurring in equal proportions. Each of the 150 enzyme molecules, e.g., N-acetylglucosaminyltransferases, should be encoded by a separate gene with a nonconserved sequence coding for the site of enzyme attachment to a strongly specific membrane site of the smooth EPR. If GAG synthesis is template-independent, at least three types of such complexes are necessary for HS generation. About 450 Nacetylglucosaminyltransferase genes are required for this process. Since the enzyme is also involved in synthesis of heparin and other polysaccharides, the number of Nacetylglucosaminyltransferase genes should occur at thousands of copies per genome. Yet it is known that DNA regions complementary to mRNAs have unique sequences and occur at a few copies per genome. Glycosyltransferase genes are not exceptions to this rule. Thus, the commonly accepted hypothesis of nontemplate synthesis of GAG cannot explain the genetically determined heterogeneity of polysaccharide components of proteoglycans. This hypothesis does not stand up, since recent works have demonstrated the informative value of the glycoside moiety of proteoglycans (Zimina N.P., et al. 1992, Zimina N.P., et al. 1987). Our scheme of template synthesis of GAG solves this problem, because only a few glycosyltransferase genes are sufficient for generating any diversity of polysaccharide

Synthesis of some glycans with a high information content according to the glycotranscription principle makes it possible to assume, by analogy with RNA, the existence of reverse glycotranscription, whereby information is transferred from polysaccharide to RNA and then, by reverse transcriptase, to DNA fragments, which can be inserted into the genome to preserve the acquired information about new glycans in the genome structure. Such information is contained in specific tandem DNA repeats, which are unique for each individual. The relevant genetic systems are probably capable of being transmitted to the progeny and being fixed as a hereditary or acquired character by selection. It seems that both nontemplate and genetically determined template synthesis of polysaccharides exist in nature and are closely associated with each other through

It should be noted in this connection that Ronichevskaya and Rykov (Ronichevskaya G.M., Rykova V.I. 1977) observed that GAG suppress DNA replication in proliferating cells in a keilon-like manner. This observation can be explained by homology of polysaccharides to NA. We think that polysaccharide fragments are capable of blocking DNA polymerases via specific binding to complementary DNA repeats. As reported earlier, the substances examined in (Ronichevskaya G.M., et al. 1977) were isolated from RNA preparations, which provides indirect evidence for a role of RNA in glycan synthesis. According to our results,

Further studies of proteoglycan polymorphism (species and tissues specificity, age- and pathological changes) and development of sequencing technique will probably demonstrate the specificity of proteoglycans at the level of individual organisms. By analogy, polymorphism of highly repetitive genome sequences is now beyond doubt and is widely used in genome fingerprinting. We assume that it is genomic repeats that are responsible for Aleksandr N. Zimnitskii *«NanoDerm-profi» Ltd., Moscow, Russia* 

## **5. References**


Colman Y., Rem C.-G. (2000). Illustrative Biochemistry. Moscow: Mir.


Lindahl U., Kjellen L.(1987). Biology of Proteoglican. Wight T.N., Mecham R.P., Eds., Orlando: Acad. Press. p. 59.

302 The Complex World of Polysaccharides

Sep;22(3):576-89.

London,178, 297.

*Rev Biochem*., 53:847-69.

*Biochem.,* 68:332-5

14, p.89-104.

*Res*.,123:361-9.

70: 414-24.

65.

carboxylate group. *J Am Chem Soc.*, 111, p.23-31.

Active Compounds. Moscow: Mosk. Gos. Univ.

dehydrogenase. *Proc. Natl. Acad. Sci. USA*, 41:253.

factor: A unique proteoglycan complex. *Biochemistry.*, 12:3045-50.

association. *Carbohydr Res.*, 16:135-44.

association. *Carbohydr Res*.,110:127-33.

assembly *Curr Opin Struct Biol*. 5:663-70.

proteoglycan synthesis. *Exp Cell Res.,* 123:229-36.

ammonia...water. *J Phys Chem.* 94, p.217-221.

mechanical molecular model. *J Am Chem Soc.*,107, p.3902-3909.

*Biochem Biophys Res Commun*., 23:641-52.

Cybulski S.M., Scheiner S.J.(1989). Hydrogen bonding and proton transfers involving the

Denhardt D.T.(1966). A membrane-filter technique for detection of complementary DNA.

Dewar M.J.S., Zoebisch E.G., Healy E.F., Stewart J.J.P. (1985). Development and use of quantum mechanical molecular models. 76. AM1: A new general purpose quantum

Dorfman A. (1958). Studies on the biochemistry of connective tissue. *Pediatrics*.

Dorfman A. (1964). Metabolism of acid mucopolysaccharides. *Biophys J*. Jan; 71:SUPPL 155-

Dorfman A.(1965). In: Structure and Function of Connective and Skeletal Tissue.

Dunin V.V., Rukhadze E.G., Potapov V.M.(1979). Generation and Analysis of Optically

Fransson L.A., Havsmark B. (1982). Structural requirements for heparan sulphate self-

Franson L.-A.(1982). Structural features of the contact zones for heparan sulphate self-

Glaser L., Brown D.H.(1955). Purification and properties of d-glucose-6-phosphate

Henkart P., Humphreys S., Humphreys T.(1973). Characterization of sponge aggregation

Hook M., Kjellen L., Jahansson S., Robinson J.(1984). Cell-surface glycosaminoglycans. *Annu* 

Jeffrey D Esko, Zhang L.(1996). Influence of core protein sequence on glycosaminoglycan

Jermyn M.A.(1975). Increasing the sensitivity of the anthrone method for carbohydrate. *Anal* 

Jurema J.M.W., Shields G.C.(1993). Ability of the PM3 quantum-mechanical method to model intermolecular hydrogen bonding between neutral molecules. *J Comput Chem.*

Kallies B., Mitzner R. (1995). The ability of the semiempirical PM3 method to model proton transfer reactions in symmetric hydrogen bonded systems. *J Mol. Model.*, 1, p.68-78. Kinoshita S., Yoshii K.(1979). The role of proteoglycan synthesis in the development of sea urchins: II. The effect of administration of exogenous proteoglycan. *Exp Cell* 

Kinoshita S., Saiga H. (1979). The role of proteoglycan in the development of sea urchins: I. Abnormal development of sea urchin embryos caused by the disturbance of

Kiselev L.L. (2000). Human genome and biology of the 21st century. *Vestn Ross Akad Nauk.,*

Latajka Z. Scheiner S.J. (1990). Structure, energetics, and vibrational spectrum of


**Coupled Mass Spectrometric Strategies for the Determination of Carbohydrates at Very Low Concentrations: The Case of Polysaccharides Involved in the Molecular Dialogue Between Plants and Rhizobia** 

V. Poinsot, M.A. Carpéné and F. Couderc

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/50069
