Biological macromolecules sugars

Biological Macromolecules Sugars and Polysaccharides Amino Acids and Proteins Nucleotides and Nucleic Acids... 

The spontaneous self-assembly or template-directed assembly of component monomeric units into polymeric biological macromolecules. 2. The enzyme-catalyzed joining of monomeric units (such as amino acids, sugars, nucleotides) into covalently linked oligomeric or polymeric forms. 

The tertiary structure of a biological macromolecule is its actual three-dimensional structure this includes not only information about the relative orientations of secondary structure elements in their backbone, but also, for example, detailed information concerning the orientations and interactions of sidechains, bases or sugar moieties. An understanding of the tertiary structure of a macromolecule is an essential step in comprehending its function, and its modes of binding to ligands or other macromolecules. 

The basic concepts of stereochemistry were independently developed by varft Hoff and Le Bel in 1874. Based on their findings Emil Fischer suggested that biological macromolecules are composed of chiral l amino acids and d sugars and in 1894 proposed his famous key and lock hypothesis that two chiral molecules interact through shape complementarity with each other and are therefore stereospecific [15]. 

Aptamers, as biosensors, find many applications. Possible aptamer ligands are proteins, other biological macromolecules, as well as the biological context in which these occur (i.e., viruses, bacteria, and eukaryotic cells). Aptamers can interact with small molecules such as metal ions and drugs, as well as primary and secondary metabolites (amino acids, nucleotides, sugars, peptides). 

As noted above, the nucleophilicity of water allows it to enter into reactions that cause the degradation of biological macromolecules, including DNA and proteins. Analogous problems are associated with the assembly of biopolymers. In water, the assembly of nucleosides from component sugars and nucleobases, the assembly of nucleotides from nucleosides and phosphate, and the assembly of oligonucleotides from nucleotides are all thermodynamically uphill in water. 

De novo synthesis of amino sugars starts from glucose-6-phosphate, but salvage pathways can also operate. Some reactions involved are shown in Figure 15-18. Incorporation of amino sugars into biological macromolecules is described in Chapter 16. 

It is well-known in contemporary science that biological macromolecules diverge from other polymeric structures. Proteins are constructed only by left-handed amino acids, whereas DNA-RNA contain only right-handed sugars (Goldanskii Semenov,... 

The interactions of biological macromolecules (proteins) with silicic acid were observed in vitro and documented by Her." He described these interactions as follows Silicic acid precipitates gelatin. . and. . albumin combines with silicic acid. It was also reported that polyalcohols and sugars did not affect the solubility of silica, but glycine reduced its rate of dissolution. Thus it was known that macromolecules interact with silica in vivo as well as in vitro, but in an unknown fashion. 

---