CRYSTALLIZATION AND PRELIMINARY-X-RAY STUDIES ON PSEUDOAZURIN FROM ACHROMOBACTER CYCLOCLASTES IAM1013

New crystals of a blue copper protein, pseudoazurin from denitrifier A chromobacter cycloclastes IAM1013, have been obtained by means of vapo r diffusion with ammonium sulfate as a precipitant at pH 6.0 and 4 deg rees C. The crystals belong to the orthorhombic system, space group P2 (1)2(1)2(1), with unit cell dimensions of a = 56.69(2), b = 61.53(2), and c = 30.20(1) Angstrom. The asymmetric unit includes one molecule o f pseudoazurin with a V-m value of 2.04 Angstrom(3)/Da. The crystals a re so stable against X-ray irradiation that a complete data set up to 1.54 a has been collected using a single native crystal. Solution of t he structure was performed by means of the Patterson search techniques , and the current crystallographic R-factor is 17.5% at 3.0 Angstrom r esolution. Refinement at higher resolution is in progress.