Heme sensing of the ChrS histidine kinase from Corynebacterium diphtheriae

迄今为止，人们认为白喉杆杆菌通过双组分信号转导系统的传感激酶（ChrS）和反应调节因子（ChrA）来利用宿主血红素铁。虽然预测ChrS编码血红素传感器，但传感机制仍未表征。在大肠杆菌膜中表达的ChrS在非离子洗涤剂的存在下被溶解和纯化。ChrS蛋白结合到蛋白脂质体和纳米盘中，通过ATP催化血红素依赖性自磷酸化。其他金属卟啉和铁不刺激激酶活性，表明ChrS是一个特定的血红素传感器。这是细菌血红素感应蛋白的第一个功能重构。

It has been hitherto believed that Corynebacterium diphteriae conducts the sensor kinase, ChrS, and the response regulator, ChrA, of a two-component signal transduction system to utilize host heme iron. Although ChrS is predicted to encode a heme sensor, the sensing mechanism remains uncharacterized. ChrS expressed in Eshcherichia coli membranes was solubilized and purified in the presence of a non-ionic detergent. ChrS protein incorporated into proteoliposomes and nanodiscs catalyzed heme-dependent autophosphorylation by ATP. Other metalloporphyrins and iron did not stimulate kinase activity, suggesting that ChrS is a specific heme sensor. This is the first functional reconstitution of a bacterial heme-sensing protein.