DNA archaea) store their DNA only in the cytoplasm. Within eukaryotic chromosomes, chromatin proteins, such as histones, compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed. DNA was first isolated by Friedrich Miescher in 1869. Its molecular structure was first identified by James Watson and Francis Crick at the Cavendish Laboratory within the University of Cambridge in 1953, whose model-building efforts were guided by X-ray diffraction data acquired by Raymond Gosling, who was a post-graduate student of Rosalind Franklin. DNA is used by researchers as a
Fiber diffraction eliminates fiber tilt, unwarps the detector image, and corrects the scattering intensity. The correct equation for the determination of β has been presented by Norbert Stribeck. Fiber diffraction data led to several important advances in the development of structural biology, e.g., the original models of the α-helix and the Watson-Crick model of double-stranded DNA. The animation shows the geometry of fiber diffraction. It is based on the notions proposed by Polanyi. Reference direction is the primary beam (label: X-ray). If the fiber is tilted away from the perpendicular direction by an angle β, as well the information about its molecular