Molecular biology, ribonucleic acid

Campbell, P.N., Smith, A.D. and Peters, TJ. (2005) Biochemistry Illustrated Biochemistry and Molecular Biology in the Post-Genomic Era, 5th edition, Elsevier, London and Oxford, 242 pp. Chapeville, F., Lipmann, F., von Ehrenstein, G., Weisblum, B., Ray, WJ. Jr. and Benzer, S. (1962) On the role of soluble ribonucleic acid in coding for amino acids, Proc. Natl. Acad. Sci. U.S.A., 48, 1086-1092. 

As much of the terminology used in molecular biology may be unfamiliar to some readers, it is appropriate to define some of the vocabulary and this is given in an appendix to this chapter. There are two types of nucleic acids, the ribonucleic acids (RNA) and the deoxyribonucleic acids (DNA). Genetic information is carried in the linear sequence of nucleotides in DNA. Each molecule of DNA contains two complementary strands of deoxyribonucleotides which contain the purine bases, adenine and guanine and the pyrimidines, cytosine and thymine. RNA is single-stranded, being composed of a linear sequence of ribonucleotides the bases are the same as in DNA with the exception that thymine is replaced by the closely related base uracil. DNA replication occurs by the polymerisation of a new complementary strand on to each of the old strands. 

Enzymes are biological catalysts, all of which are proteins, except for a class of RNA-modifying catalysts known as ribozymes ribozymes are molecules of ribonucleic acid that catalyse reactions on the phosphodiester bond of other RNAs. The International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers each enzyme is described by a sequence of one of four numbers preceded by EC . The first number broadly classifies the enzyme based on its mechanism. 

Molecular biology also involves organic chemistry, physics, and biophysical chemistry as it deals with the physicochemical structure of macromolecules (nucleic acids, proteins, lipids, and carbohydrates) and their interactions. Genetic materials including DNA in most of the living forms or RNA (ribonucleic acid) in all plant viruses and in some animal viruses remain the subjects of intense study. 

As implied in the Introduction, both proteins and (deoxy)ribonucleic acids can be viewed as ideal tyligomers—that is, the archetypal biological examples of discrete, high molecular weight macromolecules of mixed sequences with compact solution conformations assembled from many subunits of secondary structure. In our assessment of the literature, we have organized foldamer systems into four... 

In recent years, the traditional definition of biocatalysts with enzymes that are proteins having catalytic functions in biological systems was expanded to a point where a series of ribonucleic acids, called ribozymes, also acts as a biocatalyst. Much effort was devoted to developing artificial ribozymes as well. In such approaches a combination of strategies to mimic ribonucleases and to simulate complementary molecular recognition of nucleic acids is essential. 

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