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Free keywords:
Crystallization; Crystallography, X-Ray/mt [Methods]; *Cysteine Endopeptidases/ch [Chemistry]; Cysteine Endopeptidases/ip [Isolation & Purification]; *Multienzyme Complexes/ch [Chemistry]; Multienzyme Complexes/ip [Isolation & Purification]; *Protein Conformation; Support, Non-U.S. Gov't; Support, U.S. Gov't, Non-P.H.S.; Support, U.S. Gov't, P.H.S.; *Thermoplasma/en [Enzymology]
Abstract:
Single cystals of proteasomes from the archaebacterium Thermoplasma acidophilum were obtained using the hanging-drop vapor diffusion method. The crystals diffract to better than 3.0 A and belong to the orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 308.9 A, b = 208.8 A and c = 116.9 A. There is one molecular complex in the asymmetric unit. Two potentially useful heavy-atom derivatives have been obtained. The self-rotation function of the native Patterson map shows local sevenfold symmetry, consistent with the low-resolution structure obtained by electron microscopic techniques. The unit cell dimensions and crystal symmetry together with the shape and size of the proteasome suggest a packing arrangement of proteasome molecules in the unit cell, with their cylinder axis nearly parallel to the crystallographic a-axis.
