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MO: Molekülphysik

MO V: HV V

MO V.1: Hauptvortrag

Dienstag, 17. März 1998, 11:30–12:00, R712

Revealing the Backbone Structure of B-DNA with Laser Optical Simulations of its X-Ray Fiber Diagram — •A.A. Lucas — Facultés Universitaires Notre-Dame de la Paix, 61 rue de Bruxelles, B5000 Namur Belgium

Deciphering the meaning of the celebrated B-DNA X-ray fiber diagram taken by Rosalind Franklin some months before the great discovery of the double helix in 1953 has been the priviledge of very few scientists, mostly reserved to professional crystallographers. Yet this picture which, for Crick and Watson, was the most important input in arriving at the structure, can be thoroughly understood without any recourse to helical diffraction theory. In this lecture, we propose to perform optical simulations experiments capable of providing such a simple interpretation accessible to all scientists familiar with no more than the basic Thomas Young, two-slits diffraction experiment. A visible laser and a set of nine specially designed diffraction gratings held on a single slide will be used to build up progressively all the prominent features of the observed X-ray diffraction pattern and to point out each of the corresponding structural parameters of the DNA backbone. The experiment can be performed with just a laser pointer. The diffraction slide will be made available to anyone interested.