van Wezel G P, White J, Young P, Postma P W, Bibb M J
John Innes Centre, Norwich Research Park, Colney, Norwich, UK.
Mol Microbiol. 1997 Feb;23(3):537-49. doi: 10.1046/j.1365-2958.1997.d01-1878.x.
malR of Streptomyces coelicolor A3(2) encodes a homologue of the Lacl/GalR family of repressor proteins, and is divergently transcribed from the malEFG gene cluster, which encodes components of an ATP-dependent transport system that is required for maltose utilization. Transcription of malE was induced by maltose and repressed by glucose. Disruption or deletion of malR resulted in constitutive, glucose-insensitive malE transcription at a level markedly above that observed in the parental malR+ strain, and overproduction of MalR prevented growth on maltose as carbon source. Consequently, MalR plays a crucial role in both substrate induction and glucose repression of maltose utilization. malR is expressed from a single promoter with transcription initiating at the first G of the predicted GTG translation start codon.
天蓝色链霉菌A3(2)的malR编码一种阻遏蛋白Lacl/GalR家族的同源物，并且与malEFG基因簇呈反向转录，malEFG基因簇编码麦芽糖利用所需的ATP依赖性转运系统的组分。malE的转录由麦芽糖诱导并被葡萄糖抑制。malR的破坏或缺失导致组成型的、对葡萄糖不敏感的malE转录，其水平明显高于亲本malR+菌株中观察到的水平，并且MalR的过量产生阻止了以麦芽糖作为碳源的生长。因此，MalR在麦芽糖利用的底物诱导和葡萄糖阻遏中都起着关键作用。malR从单个启动子表达，转录起始于预测的GTG翻译起始密码子的第一个G。
