CRYSTALLIZATION AND PRELIMINARY X-RAY STRUCTURANALYSIS OF THE STRUCTURAL DOMAIN E OF THERMUS FLAVUS 5S rRNA. Markus Perbandt^*, Alexis Nolte^*, Siegfried Lorenz^*, Jens Peter Fuerste^*, Christian Betzel^**, Volker A. Erdmann^*, ^*Institute of Biochemistry, Freie Universitaet Berlin, Thielallee 63,14195 Berlin, Germany, ^**Institute of Physiological Chemistry, University of Hamburg, 20246 Hamburg, Germany

The ribosomal 5S RNA is an essential constituent of the large ribosomal subunit. To overcome the difficulties of crystallizing large RNA molecules such as 5S rRNA, we decided to devide the 5S rRNA in five domains A through E to determine their structure. Recently we determined the crystal structural of the helical domain A. Here we report the preliminary structural results of the chemically synthesized domain E of the Thermus flavus 5S rRNA. The crystal form is trigonal with cell dimension: a = b = 42.80 Å and c = 162.20 Å. Diffraction-data to 2.8 Å have been recorded and the structure solution is currently underway by means of MIR and MAD techniques.