A new crystal form of proteinase A, a non-pepsin-type acid proteinase from Aspergillus niger var. macrosporus.
Proteinase A from Aspergillus niger var. macrosporus is a non-pepsin-type acid proteinase, whose catalytic residues and mechanism remain to be elucidated. A new form of proteinase A crystals more suitable for crystallography than that obtained previously was prepared from an ammonium sulfate solution at pH 3.5 by the hanging-drop vapor diffusion method. The space group of the crystals was P2(1)2(1)2(1), with unit cell dimensions of a = 69.75 +/- 0.06 A, b = 87.55 +/- 0.05 A, and c = 60.83 +/- 0.04 A. On the assumption of two enzyme molecules per asymmetric unit, the calculated volume to unit protein mass ratio (Vm) was 2.08 A3/Da. By assuming the specific volume to be 0.74 cm3/g, the solvent content (Vso1) was estimated to be 41%, i.e., much larger than that of the crystal form obtained previously at pH 2.0 (Vso1 = 26%). Diffraction data were collected up to a resolution higher than 1.6 A, using the Weissenberg camera for macromolecular crystallography with synchrotron radiation.
Tanokura
M
M
Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo.
Sasaki
H
H
Muramatsu
T
T
Iwata
S
S
Hamaya
T
T
Takizawa
T
T
Takahashi
K
K
D000645:Ammonium Sulfate; D016282:Aspartic Acid Endopeptidases / Q000737:chemistry*; D001234:Aspergillus niger / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray; D004058:Diffusion; D006863:Hydrogen-Ion Concentration
C022325:aspartic proteinase A; D016282:Aspartic Acid Endopeptidases; D000645:Ammonium Sulfate