A DNA fragment from Bacillus subtilis strain Marburg coding for the synthesis of an enzyme catalyzing sucrose hydrolysis was cloned in Escherichia coli and detected using simple direct selection of transformants growing on sucrose. Three different clones were obtained each having a 2.5 kb EcoRI-Pstl fragment in common which was shown to be sufficient to mediate growth on sucrose. This fragment was not identical with known cloned gene fragments of B. subtilis coding for the sucrose hydrolyzing enzymes sucrase and levansucrase. It could be shown that the 2.5 kb fragment codes for a third sucrose hydrolyzing enzyme, namely for levanase. In the case of E. coli this enzyme was found to be mainly intracellular; however, a small quantity was also excreted into the periplasmic space.
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