Identification and characterization of 2-keto-3-deoxy-l-rhamnonate dehydrogenase belonging to the MDR superfamily from the thermoacidophilic bacterium Sulfobacillus thermosulfidooxidans: implications to lrhamnose metabolism in archaea
Identification and characterization of 2-keto-3-deoxy-l-rhamnonate dehydrogenase belonging to the MDR superfamily from the thermoacidophilic bacterium Sulfobacillus thermosulfidooxidans: implications to lrhamnose metabolism in archaea
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DOI：
10.1007/s00792-015-0731-8
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发表时间：
2015-03-01
期刊：
影响因子：
2.9
通讯作者：
Lee, Sun Bok
中科院分区：
文献类型：
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作者：
Bae, Jungdon;Kim, Suk Min;Lee, Sun Bok
我们在嗜热嗜酸细菌sulobacillus thermosulfidooxidans基因组中发现了非磷酸化的l-鼠李糖代谢途径（Rha_NMP）基因，这些基因与嗜热嗜酸古菌Thermoplasma acidophilum中的基因同源。然而，与之前已知的2-酮-3-脱氧-l-鼠李糖酸酯（l-KDR）脱氢酶（KDRDH）属于短链脱氢酶/还原酶超家族不同，S. thermosulfidooxidans （Sulth_3557）和T. acidophilum （Ta0749）中的KDRDH属于中链脱氢酶/还原酶（MDR）超家族。我们证实了S. thermosulfidooxidans中的Sulth_3559和Sulth_3557蛋白分别具有l-鼠李糖脱氢酶和KDRDH的功能。Sulth_3557蛋白是一种NAD（+）特异性KDRDH，其最适温度和pH分别为50℃和9.5℃。l-KDR的K (m)和V （max）值分别为2.0 mM和12.8 U/mg。Sulth_3557也表现出较弱的2,3-丁二醇脱氢酶活性。系统发育分析表明，Sulth_3557及其同源物在MDR超家族中形成了一个新的亚家族。本研究结果表明，嗜热酸性古细菌与嗜热酸性细菌S. thermosulfidooxidans类似，利用耐多药家族KDRDH将l-鼠李糖代谢为丙酮酸盐和l-乳酸盐。
We identified the non-phosphorylated l-rhamnose metabolic pathway (Rha_NMP) genes that are homologous to those in the thermoacidophilic archaeon Thermoplasma acidophilum in the genome of the thermoacidophilic bacterium Sulfobacillus thermosulfidooxidans. However, unlike previously known 2-keto-3-deoxy-l-rhamnonate (l-KDR) dehydrogenase (KDRDH) which belongs to the short chain dehydrogenase/reductase superfamily, the putative KDRDHs in S. thermosulfidooxidans (Sulth_3557) and T. acidophilum (Ta0749) belong to the medium chain dehydrogenase/reductase (MDR) superfamily. We demonstrated that Sulth_3559 and Sulth_3557 proteins from S. thermosulfidooxidans function as l-rhamnose dehydrogenase and KDRDH, respectively. Sulth_3557 protein is an NAD(+)-specific KDRDH with optimal temperature and pH of 50 A degrees C and 9.5, respectively. The K (m) and V (max) values for l-KDR were 2.0 mM and 12.8 U/mg, respectively. Sulth_3557 also showed weak 2,3-butanediol dehydrogenase activity. Phylogenetic analysis suggests that Sulth_3557 and its homologs form a new subfamily in the MDR superfamily. The results shown in this study imply that thermoacidophilic archaea metabolize l-rhamnose to pyruvate and l-lactate by using the MDR-family KDRDH similarly to that of the thermoacidophilic bacterium S. thermosulfidooxidans.