Teaching a course on nucleic acid structure is a hazardous undertaking, especially if one has no continuous teaching obligations. I still have done it on several occasions in various French universities, when colleagues, suffering from admin istrative overwork and excessive teaching obligations, had asked me to do so. This was generally done with a pile of notes and a dozen slides, and I always regretted that no small, concise, specialized book on nucleic acid structure for students at the senior or beginning graduate level ex isted. Every year, the lecture notes became more and more voluminous, with some key reprints intermingled. Everything changed when, in the spring of 1973, I re ceived an invitation to teach such a course, under the UNESCO-OAS-Molecular Biology Program at the Universi dad de Chile in Santiago during October 1973. I had ac cepted rather enthusiastically, but soon discovered that it would be necessary to produce a photocopied syllabus for the students. This was the fi rst premanuscript of this book. For nonscientific reasons, the course was first canceled and then postponed until December 1973. Nearly a year later, the course, in slightly amended form, was presented at the Lemonossow-State University in Moscow.

Inhalt
1 Introduction.- 1.1 History.- 1.2 Cellular localization of nucleic acids.- 2 Methods and Techniques.- 2.1 Absorption and optical activity (ORD and CD).- 2.2 Nuclear magnetic resonance (NMR).- 2.3 Ultracentrifugation.- 2.4 X-ray fiber diffraction.- 3 Chemistry and Enzymology of Nucleic Acids.- 3.1 Chemistry of nucleic acids and their constituents.- 3.2 Chemical reactions of nucleic acids and their constituents.- 3.3 Isolation of nucleic acids.- 3.4 Degradation and determination of nucleic acids.- 4 Structure and Function of DNA.- 4.1 The double helix of Watson and Crick.- 4.2 Experimental tests of the Watson-Crick hypothesis.- 4.3 The role of DNA in the cellular machinerythe central dogma.- 5 Physical Chemistry of DNAThe Problems of DNA Research.- 5.1 Established facts.- 5.2 Facts that may require amendments of details of the WatsonCrick theory.- 5.3 What do we require from biologically operative DNA?.- 5.4 What do we still not know?.- 6 Model Systems for Nucleic Acids.- 6.1 Polynucleotides.- 6.2 Oligonucleotides.- 6.3 Association of monomers in solutions and crystals.- 7 Errors and Mutations.- 7.1 Chemical mutagenesis.- 7.2 Base analogues.- 7.3 Antibiotics, pigments, dyes.- 7.4 Mutagenesis by radiation (UV, X-rays).- 8 The Structure of Ribonucleic Acids.- 8.1 Protein biosynthesis.- 8.2 Transfer RNA.- 8.3 Ribosome structure and rRNA.- 8.4 Viral RNA and virus structure.- 9 Nucleic AcidProtein Interactions.- 9.1 Polyamines.- 9.2 Polypeptides and protamines.- 9.3 Histones and chromatin.- In the Guise of an Epilogue.- Appendix: Abbreviations and Symbols for Nucleic Acids, Polynucleotides, and Their Constituents.- Suggested Bibliography for Advanced Reading.