CRYSTALLIZATION AND PRELIMINARY STRUCTURAL STUDIES OF NEUROTROPHIN-3

Neurotrophin-3 (NT-3) has been crystallized in 2 forms. Orthorhombic c rystals, space group P2(1)2(1)2, diffracted to 2.8 Angstrom and have c ell dimensions a = 39.1 Angstrom, b = 54.0 Angstrom, and c = 65.5 Angs trom. The second form is space group P4(3)2(1)2, with cell dimensions a = b = 67.1 Angstrom, and c = 107.9 Angstrom. The tetragonal crystals diffract to 2.8 Angstrom at room temperature and 2.5 Angstrom at -100 degrees C. The unit cell dimensions change significantly upon freezin g, a = b = 66.1 Angstrom, and c = 102.8 Angstrom. Phases for the ortho rhombic form were obtained by molecular replacement using nerve growth factor as the search model. A partially refined model of the NT-3 dim er (75% complete) was then oriented and positioned in the tetragonal c ell.