Elucidation of novel archaeal mevalonate pathways oriented to metabolic engineering application

古生菌甲羟戊酸途径中的部分反应尚未确定。因此，我们利用古生菌的无细胞提取物进行了放射性标记底物的转化试验，并对已知的甲氧戊酸途径相关酶的古生菌同源物进行了功能鉴定。因此，我们从硫磺属古生物中发现了古生菌中罕见的经典甲戊酸途径，并从热质属古生菌中发现了一种新的经过3-磷代戊酸的修饰途径。我们还对硫柳属古菌中的2型异戊烯基二磷酸异构酶和二磷代戊酸脱羧酶进行了X射线晶体结构研究。所获得的结构和各种分析的结果显示了新的催化、活性调节和热稳定机制。

A part of reactions in the archaeal mevalonate pathways were unidentified. Thus we performed the conversion assay of radio-labeled substrates by cell-free extract from archaea and functional characterization of archaeal homologs of known mevalonate pathway-related enzymes. As the result, we discovered the classical mevalonate pathway, which is rare in archaea, from an archaeon of genus Sulfolobus, and a novel modified pathway, which passes through 3-phosphomevalonate, from an archaeon of genus Thermoplasma.We also performed X-ray crystal structural studies on type 2 isopentenyl diphosphate isomerase and diphosphomevalonate decarboxylase from archaea of genus Sulfolobus. The obtained structures and the results of various analyses showed novel mechanisms of catalysis, regulation of activity, and thermostabilization.