SEQUENCE AND REGULATION OF VITAMIN K BIOSYNTHESIS GENES

本次调查的主要目的是了解法规 参与维生素K的基因和酶的表达 生物合成途径 维生素K是一种重要的脂溶性维生素， 是人类和动物健康所必需的。 维生素K 反应性低凝血原症是一个重要的临床问题， 条件的数量。 人体肠道的细菌植物群 提供人体所需维生素K的50-100%。 维生素K来源于“莽草酸途径”，它是由 异分支酸和2-酮戊二酸。 中间体已经被 鉴定为2-琥珀酰基-6-羟基-2，4-环己二烯-1-羧酸酯 （SHCHC）、邻琥珀酰苯甲酸酯（OSB）、OSB的CoA酯（OSB-CoA）、1，4-丁二酰苯甲酸酯（OSB）、 二羟基-2-萘甲酸酯（DHNA）和去甲基甲萘醌（DMK）。 位于染色体48.5 min处的menD、C、E和B基因， 被克隆和测序。 menA基因在89分钟时的测序是 我们将鉴定并克隆转化基因 DMK-MK。 为了克服工作中的困难， 大量的酶和中间体，我们将使用操纵子和蛋白质 融合来研究调控，我们将把基因引入 过量表达载体来过量生产、纯化和研究酶， 途径的中间体。

The principal aim of this investigation is to understand the regulation of expression of the genes and enzymes involved in the vitamin K biosynthetic pathway. Vitamin K is an important fat soluble vitamin that is required for the well being of humans and animals. Vitamin K responsive hypoprothrombia is an important clinical problem under a number of conditions. The bacterial flora of the human intestine contribute from 50-100% of the human vitamin K requirement. Vitamin K is derived from the "shikimate pathway" and it is formed from isochorismate and 2-ketoglutarate. The intermediates that have been identified are 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC), o-succinylbenzoate (OSB), a CoA ester of OSB (OSB-CoA), 1,4- dihydroxy-2-naphthoate (DHNA), and desmethylmenaquinone (DMK). The menD, C, E, and B genes located at 48.5 min of the chromosome have been cloned and sequenced. The sequencing of the menA gene at 89 min is in progress and we will identify and clone the gene for the conversion of DMK---> MK. To overcome the difficulty of working with small quantities of enzymes and intermediates, we will use operon and protein fusions to study regulation and we will introduce the genes into overexpression vectors to overproduce, purify and study the enzymes and intermediates of the pathway.