【摘 要】
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The marine bacterium strain Rhodococcus sp.P14 is known for its steroiddegrading.By analyzing its genome sequence,a novel short-chain dehydrogenase/reductase (SDR) gene was identified at the location
【机 构】
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Department of Biology, College of Science, Shantou University, Shantou, China
【出 处】
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第二十次全国环境微生物学学术研讨会
论文部分内容阅读
The marine bacterium strain Rhodococcus sp.P14 is known for its steroiddegrading.By analyzing its genome sequence,a novel short-chain dehydrogenase/reductase (SDR) gene was identified at the location (nucleotides 3747518 to 3748357) nearby the functional gene 17β-hydroxysteroid dehydrogenase(17β-HSD).The amino acid identity between the SDR and 17β-HSD1 of the strain P 14 was 29.79%.Expression of SDR could be induced by estradiol in strain P14.To reveal its function,the recombinant SDR protein was expressed in Escherichia coli.The results showed that the recombinant cells harbor a high transformation rate for estradiol (61.19%±2.59) and testosterone (78.2%±3.61) within 72 h.By analyzing its enzyme activity toward various steroid substrates,it showed that the recombinant SDR was able to convert estrogens more efficiently than androgens.Moreover,SDR specifically oxidized the substrates at the C17 position rather than the C3 and C20 position,hence it was named as 17β-HSD2.This is the first time to demonstrate that 17β-hydroxysteroid dehydrogenase can covert both estradiol and testosterone.
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