Principles of nucleic acid structure

A wide variety of crystal structure studies have been done on parts of an antibody and these have led to an overall detailed three-dimensional structure. In addition, the structures of an antibody-antigen complex (Amit et al 1986) and a neuraminidase-antibody complex (Colman et al 1987) have been determined. 

The genetic information is contained within the chemical structure of DNA, deoxyribonucleic acid, namely the sequence of bases along the polynucleotide chain. RNA, ribonucleic acid, is used by an organism to act as a messenger between the genes and the site of protein synthesis, the ribosome. The genes of all cells and many viruses are made of DNA. 

Some viruses, however, use RNA as their genetic material. A virus is a complex composed of protein and nucleic acid. Vast quantities of information have to be stored in the DNA sequences in complex organisms. The chromosomes have a distinct structural character that allows a condensation of the volume of DNA which is necessary to encode the information required to specify all the proteins in a given organism. A fundamental unit within the chromosome, for packing the DNA, is a nucleosome, a complex of proteins and DNA. The genetic information is converted into a specific protein at the ribosome, the site of protein synthesis within the cell. The ribosome is also a complex of proteins and RNA molecules. Ciystals of viruses, the ribosome and nucleosomes require SR, in whole or in part, for their structural elucidation. To understand these structures and the role of the synchrotron in their X-ray analyses we must first explain the principles of nucleic acid structure. 

DNA is a polymer of deoxyribonucleotide units. A nucleotide consists of a nitrogenous base, a sugar and one or more phosphate groups. The sugar in a deoxyribonucleotide is deoxyribose. The base is a purine or pyrimidine. The purines in DNA are adenine (A) and guanine (G) and the pyrimidines are thymine (T) and cytosine (C) (figure 3.17). 

The three-dimensional structure of DNA was deduced by Watson and Crick (1953) by analysing X-ray fibre diffraction photographs of DNA fibres recorded by Franklin and Wilkins (Franklin and Gosling 1953). This structure for DNA was arrived at by building a model which could explain the basic features of the fibre pattern. 

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W Saenger. Principles of Nucleic Acid Structure. New York Sprmger-Verlag, 1984. 

Saenger W (1984) Principles of nucleic acid structure. Springer, Berlin Heidelberg... 

Saenger, W. "Principles of Nucleic Acid Structure." Springer-Verlag New York, 1984. 

Figure 2.16 Orientations found in DNA helices. (Adapted with permission from Figure 2.11 of Saenger, W. Principles of Nucleic Acid Structure, Springer-Verlag, New York, 1984 copyright 1984, Springer-Verlag, New York and Figure 1.22 A, B, C of Cowan, J. A. Inorganic Biochemistry, An Introduction, 2nd ed., Wiley-VCH, New York, 1997. Copyright 1997, Wiley-VCH.)...

Saenger W (1984) Principles of nucleic acid structure. Springer-Verlag, New York Sastry M, Fiala R, Patel DJ (1995) Solution structure of mithramycin dimers bound to partially overlapping sites on DNA. J Mol Biol 251 674-689 Schafer S, Jung M (2005) Chromatin modifications as targets for new anticancer drugs. Arch Pharm (Weinheim) 338(8) 347-357... 

W. Saenger, tRNA - A Treasury of Stereochemical Information. In Principles of Nucleic Acid Structure C. R. Cantor, Ed. Springer-Verlag New York, 1984 pp 331-349. 

Figure 10.26 Appearance of the two types of nucleosomes. The cores are histone octamers, around which is wound the double-stranded DNA. The cylindrical object in the right frame represents HI histones. (Reproduced by permission from Saenger W. Principles of Nucleic Acid Structure. New York Springer-Verlag, 1984, p. 442.)...

W. Saenger, Principles of Nucleic Acid Structure, Springer Advanced Texts in Chemistry, ed. C.R. Cantor (Springer-Verlag, New York, 1984). 

Roberts, R. J. (1988). Restriction Enzymes and Their Isoschizomers. Nucleic Acids Res (suppl) 16 r271. Saenger, W. (1984). Principles of Nucleic Acid Structure. 

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