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Expression, purification, crystallization and preliminary X-ray analysis of Escherichia coli argininosuccinate
1Structural Biology and Biochemistry, Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, M5G 1X8, Ontario, Canada.
Abstract:
A recombinant form of Escherichia coli argininosuccinate synthetase with a C-terminal polyhistidine affinity tag has been expressed, purified and subsequently crystallized using the hanging-drop vapour-diffusion technique. The crystals grow as large rectangular chunks with unit-cell dimensions a = 79.70, b = 105.84, c = 127.33 A, alpha = beta = gamma = 90 degrees. The crystals exhibit the symmetry of space group I222 and diffract to a minimum d-spacing of 1.6 A at station X8C of the National Synchrotron Light Source, Brookhaven National Laboratory. On the basis of density calculations, one monomer of this homotetrameric protein is predicted per asymmetric unit (Matthews coefficient V(m) = 2.69 A(3) Da(-1)).