Abstract：
Heme-based sensor proteins are used by organisms to control signaling and physiological effects in response to their gaseous environment. Globin-coupled sensors (GCS) are oxygen-sensing proteins that are widely distributed in bacteria. These proteins consist of a heme globin domain linked by a middle domain to various output domains, including diguanylate cyclase domains, which are responsible for synthesizing c-di-GMP, a bacterial second messenger crucial for regulating biofilm formation. To understand the roles of heme pocket residues in controlling activity of the diguanylate cyclase domain, variants of the Pectobacterium carotovorum GCS (PccGCS) were characterized by enzyme kinetics and resonance Raman (rR) spectroscopy. Results of these studies have identified roles for hydrogen bonding and heme edge residues in modulating heme pocket conformation and flexibility. Better understanding of the ligand-dependent GCS signaling mechanism and the residues involved may allow for future development of methods to control O2-dependent c-di-GMP production.
摘要：
基于血红素的传感器蛋白被生物体用于响应于其气体环境来控制信号传导和生理效应。珠蛋白偶联传感器(GCS)是广泛分布于细菌中的氧传感蛋白。这些蛋白质由血红素珠蛋白结构域组成，该结构域通过中间结构域与各种输出结构域相连，包括二鸟苷酸环化酶结构域，负责合成c-di-GMP，对调节生物膜形成至关重要的细菌第二信使。为了了解血红素口袋残基在控制双鸟苷酸环化酶结构域活性中的作用，通过酶动力学和共振拉曼（rR）光谱表征了类胡萝卜素烟杆菌GCS（PccGCS）的变体。这些研究的结果已经确定了氢键和血红素边缘残基在调节血红素袋构象和柔性中的作用。对配体依赖性GCS信号传导机制和所涉及的残基的更好理解可以允许将来开发控制O2依赖性c-di-GMP产生的方法。
