Noach Ilit, Lamed Raphael, Xu Qi, Rosenheck Sonia, Shimon Linda J W, Bayer Edward A, Frolow Felix
Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 68790, Israel.
Acta Crystallogr D Biol Crystallogr. 2003 Sep;59(Pt 9):1670-3. doi: 10.1107/s0907444903014094. Epub 2003 Aug 19.
The N-terminal type II cohesin from the cellulosomal ScaB subunit of Acetivibrio cellulolyticus was crystallized in two different crystal systems: orthorhombic (space group P2(1)2(1)2(1)), with unit-cell parameters a = 37.455, b = 55.780, c = 87.912 A, and trigonal (space group P3(1)21), with unit-cell parameters a = 55.088, b = 55.088, c = 112.553 A. The two crystals diffracted to 1.2 and 1.9 A, respectively. A selenomethionine derivative was also crystallized and exhibited trigonal symmetry (space group P3(1)21), with unit-cell parameters a = 55.281, b = 55.281, c = 112.449 A and a diffraction limit of 1.97 A. Initial phasing of the trigonal crystals was successfully performed by the SIRAS method using Cu Kalpha radiation with the selenomethionine derivative as a heavy-atom derivative. The structure of the orthorhombic crystal form was solved by molecular replacement using the coordinates of the trigonal form.
