Okazaki Institute of Natural Sciences, National Institutes of Natural Sciences, Myodaiji, Okazaki, Japan.
Antioxid Redox Signal. 2012 Apr 1;16(7):678-86. doi: 10.1089/ars.2011.4248. Epub 2011 Oct 19.
Gas molecules function as signaling molecules in many biological regulatory systems responsible for transcription, chemotaxis, and other complex physiological processes. Gas sensor proteins play a crucial role in regulating such biological systems in response to gas molecules.
New sensor proteins that sense oxygen or nitric oxide have recently been found, and they have been characterized by X-ray crystallographic and/or spectroscopic analysis. It has become clear that the interaction between a prosthetic group and gas molecules triggers dynamic structural changes in the protein backbone when a gas sensor protein senses gas molecules. Gas sensor proteins employ novel mechanisms to trigger conformational changes in the presence of a gas.
In gas sensor proteins that have iron-sulfur clusters as active sites, the iron-sulfur clusters undergo structural changes, which trigger a conformational change. Heme-based gas sensor proteins reconstruct hydrogen-bonding networks around the heme and heme-bound ligand.
Gas sensor proteins have two functional states, on and off, which are active and inactive, respectively, for subsequent signal transduction in response to their physiological effector molecules. To fully understand the structure-function relationships of gas sensor proteins, it is vital to perform X-ray crystal structure analyses of full-length proteins in both the on and off states.
气体分子在许多负责转录、趋化性和其他复杂生理过程的生物学调节系统中充当信号分子。气体传感器蛋白在响应气体分子调节此类生物系统方面起着至关重要的作用。
最近发现了新的氧气或一氧化氮传感器蛋白，并通过 X 射线晶体学和/或光谱分析对其进行了表征。当气体传感器蛋白感知气体分子时，它清楚地表明，当气体传感器蛋白感知气体分子时，与辅基和气体分子的相互作用会引发蛋白质骨架的动态结构变化。气体传感器蛋白采用新颖的机制在存在气体的情况下引发构象变化。
在以铁硫簇作为活性位点的气体传感器蛋白中，铁硫簇会发生结构变化，从而引发构象变化。基于血红素的气体传感器蛋白会重建血红素周围的氢键网络以及血红素结合配体。
气体传感器蛋白有两种功能状态，开和关，分别对应于其生理效应分子的后续信号转导的活性和非活性状态。为了充分理解气体传感器蛋白的结构-功能关系，对开和关两种状态下全长蛋白进行 X 射线晶体结构分析至关重要。
