Overproduction and crystallization of tryptophanase from recombinant cells of Escherichia coli |
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Authors: | S Tani N Tsujimoto Y Kawata M Tokushige |
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Affiliation: | Department of Chemistry, Faculty of Science, Kyoto University, Japan. |
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Abstract: | We have cloned the tryptophanase structural gene from Escherichia coli B/1t7-A into E. coli K-12 MD55 with a vector plasmid, pBR322. The cloned cells produced a large amount of the enzyme corresponding to more than 30% of the total soluble protein. With the enzyme obtained by this overproduction system, we have prepared three different crystals of tryptophanase, apo-enzyme, holo-enzyme, and a complex of holo-enzyme and L-alanine, by using polyethylene glycol 4000 or potassium phosphate as a precipitant and the hanging drop method. These single crystals appeared to be suitable for X-ray diffraction analysis. |
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