Characterization of a bifunctional specific regulator for genes involved in maltodextrin transport and metabolism in Thermococcus litoralis

超嗜热古菌Thermococcus litoralis含有一个高亲和力和结合蛋白依赖性的海藻糖和麦芽糖转运系统，该系统由培养基中的海藻糖特异性诱导。该提案旨在鉴定和表征该系统的特定基因调节剂。提出的鉴定策略基于以下几个发现：i，MalK的结构，转运蛋白的ATP结合亚基，揭示了在大肠杆菌中的嗜温同源物中也发现的保守结构域，其唯一的功能是与其特定的基因调节剂相互作用。因此，MalK的Thermococcus litoralis将被用于在一个生化方法，以确定的基因调节器，预计将与它相互作用。ii，编码整个ABC转运蛋白的基因簇包含在一个16 kb的DNA片段中的Thermococcus litoralis已被移动到激烈的热球菌通过水平基因转移。必需的调节元件必须包含在该16 kb片段上，因为该系统在新宿主中表现出相同的诱导性。因此，我们将在E.大肠杆菌中包含的这个片段，并测试他们的产品与MalK相互作用的能力，并作为转录调节因子。

The hyperthermophilic archaeon Thermococcus litoralis contains a high affinity and binding protein-dependent transport system for trehalose and maltose that is specifically induced by trehalose in the medium. The proposal aims at the identification and characterization of the specific gene regulator of this system. The proposed strategy for the identification is based on several findings: i, the structure of MalK, the ATP-binding subunit of the transporter, reveals a conserved domain found also in the mesophilic homologue in Escherichia coli whose only function is to interact with its specific gene regulator. Thus, MalK of Thermococcus litoralis will be used in a biochemical approach to identify the gene regulator that is expected to interact with it. ii, the gene cluster encoding the entire ABC transporter is contained in a 16kb DNA fragment in Thermococcus litoralis that has been moved into Pyrococcus furiosus by horizontal gene transfer. The necessary regulatory elements must be contained on this 16 kb fragment since the system exhibits the same inducibility in the new host. Thus, we will express genes in E. coli contained in this fragment and test their products for the ability to interact with MalK and to act as transcriptional regulators.