Schiering N, Tao X, Zeng H, Murphy J R, Petsko G A, Ringe D
Department of Chemistry, Brandeis University, Waltham, MA 02154, USA.
Proc Natl Acad Sci U S A. 1995 Oct 10;92(21):9843-50. doi: 10.1073/pnas.92.21.9843.
The diphtheria tox repressor (DtxR) of Corynebacterium diphtheriae plays a critical role in the regulation of diphtheria toxin expression and the control of other iron-sensitive genes. The crystal structures of apo-DtxR and of the metal ion-activated form of the repressor have been solved and used to identify motifs involved in DNA and metal ion binding. Residues involved in binding of the activated repressor to the diphtheria tox operator, glutamine 43, arginine 47, and arginine 50, were located and confirmed by site-directed mutagenesis. Previous biochemical and genetic data can be explained in terms of these structures. Conformational differences between apo- and Ni-DtxR are discussed with regard to the mechanism of action of this repressor.
白喉棒状杆菌的白喉毒素阻遏蛋白（DtxR）在白喉毒素表达调控及其他铁敏感基因的控制中发挥着关键作用。已解析了脱辅基DtxR及金属离子激活形式阻遏蛋白的晶体结构，并用于鉴定参与DNA和金属离子结合的基序。通过定点诱变确定并证实了参与激活阻遏蛋白与白喉毒素操纵基因结合的残基，即谷氨酰胺43、精氨酸47和精氨酸50。先前的生化和遗传学数据可根据这些结构来解释。针对该阻遏蛋白的作用机制，讨论了脱辅基DtxR和镍-DtxR之间的构象差异。
