CRYSTALLIZATION AND PRELIMINARY-X-RAY ANALYSIS OF THE MAJOR ENDOGLUCANASE FROM THERMOASCUS-AURANTIACUS

The major endoglucanase (35 kDa) from the thermophilic fungus Thermoas cus aurantiacus has been purified from culture filtrates using an affi nity method and the sequence for 35 N-terminal amino acids determined. This has allowed assignment of the enzyme to subtype A6 of family 5 e ndoglucanases. The enzyme has been crystallized as thick plates by the hanging-drop method using ammonium sulfate as precipitant. The crysta ls belong to space group P2(1)2(1)2(1) with cell edges a = 76.4, b = 8 5.7 and c = 89.5 Angstrom, with two molecules in the asymmetric unit, and diffract to 1.62 Angstrom resolution using synchrotron radiation. The structure will be solved by isomorphous replacement.