An Escherichia coli Mutant Having Altered D-Xylose Uptake Activity and Cloning of a Gene for D-Xylose Uptake |
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Authors: | Naotaka Kurose Kousaku Murata Akira Kimura |
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Affiliation: | 1. Central Research laboratories, Takara Shuzo, Co., Ltd, Otsu, Shiga, 520-21, Japan;2. Research Institute for Food Science, Kyoto University, Uji, Kyoto, 611, Japan |
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Abstract: | An Escherichia coli C600 mutant having an altered D-xylose uptake activity was isolated. The growth rate and D-xylose uptake activity of the mutant grown on the minimal medium with D-xylose at 25°C were much lower than those of the parental strain grown under the same conditions, although the activities of D-xylose-binding proteins and the enzymes involved in D-xylose metabolism were almost the same for the two strains. An uptake study on sugars at the low temperature (25°C) indicated that the mutant was deficient in D-xylose uptake activity. A gene responsible for the D-xylose uptake activity at the low temperature was isolated and cloned onto vector plasmid pBR322. The gene specifically improved the D-xylose uptake activity of the mutant at the low temperature when it was introduced into the mutant cells. Based on these results, it was suggested that another D-xylose transport system other than the D-xylose-binding protein mediated system might be functioning in E. coli cells. |
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