Borczuk A, Staub A, Stock J
Biochem Biophys Res Commun. 1986 Dec 30;141(3):918-23. doi: 10.1016/s0006-291x(86)80130-9.
The CheB methylesterase catalyzes the demethylation of membrane receptors during chemotaxis in Salmonella typhimurium. The kinetic properties of the full length product of the cheB gene are compared to those of the isolated C-terminal catalytic domain. The fragment has at least a 15-fold higher specific activity than the intact protein. In intact cells receptor demethylation is inhibited by attractants such as L-aspartate. We show here that both forms of the enzyme are similarly inhibited in vitro. Thus, the C-terminal catalytic domain of the CheB protein is sufficient for this aspect of esterase regulation. Inhibition by attractants appears to be caused by changes in receptor conformation rather than by changes in the activity of the demethylating enzyme.
CheB 甲基酯酶在鼠伤寒沙门氏菌趋化作用期间催化膜受体的去甲基化。将 cheB 基因全长产物的动力学特性与分离出的 C 末端催化结构域的动力学特性进行比较。该片段的比活性比完整蛋白质至少高 15 倍。在完整细胞中，受体去甲基化受到 L-天冬氨酸等引诱剂的抑制。我们在此表明，两种形式的酶在体外受到类似的抑制。因此，CheB 蛋白的 C 末端催化结构域足以实现酯酶调节的这一方面。引诱剂的抑制作用似乎是由受体构象的变化而非去甲基化酶活性的变化引起的。
