Hou S, Belisle C, Lam S, Piatibratov M, Sivozhelezov V, Takami H, Alam M
Department of Microbiology, Snyder Hall 207, 2538 The Mall, University of Hawaii, Honolulu, Hawaii 96822, USA.
Extremophiles. 2001 Oct;5(5):351-4. doi: 10.1007/s007920100220.
We have recently discovered heme-containing signal transducers from the archaeon Halobacterium salinarum (HemAT-Hs) and the gram-positive bacterium Bacillus subtilis (HemAT-Bs). These proteins bind diatomic oxygen and trigger aerotactic responses. We identified that HemAT oxygen-sensing domains contain a globin-coupled sensor (GCS) motif, which exists as a two-domain transducer, having no similarity to the PAS domain (Period circadian protein, Ah receptor nuclear translocator protein, Single-minded protein) superfamily transducers. Using the GCS motif, we predicted that a 439-amino-acid protein annotated as a methyl-accepting chemotaxis protein (MCP) in the facultatively alkaliphilic bacterium Bacillus halodurans is a globin-coupled oxygen sensor. We cloned, expressed, and purified GCS(Bh), and performed its spectral analysis. GCS(Bh), binds heme and shows myoglobin-like spectra. This suggests that GCS(Bh) acts as an oxygen sensor and transmits a conformational signal through a linked signaling domain to trigger an aerotactic response in B. halodurans.
我们最近从嗜盐古菌盐沼盐杆菌（HemAT-Hs）和革兰氏阳性细菌枯草芽孢杆菌（HemAT-Bs）中发现了含血红素的信号转导蛋白。这些蛋白质结合双原子氧并触发趋氧反应。我们确定HemAT氧感应结构域包含一个球蛋白偶联传感器（GCS）基序，它作为一个双结构域转导蛋白存在，与PAS结构域（周期昼夜蛋白、芳烃受体核转运蛋白、单 minded蛋白）超家族转导蛋白没有相似性。利用GCS基序，我们预测在兼性嗜碱细菌嗜碱芽孢杆菌中一个注释为甲基接受趋化蛋白（MCP）的439个氨基酸的蛋白质是一个球蛋白偶联氧传感器。我们克隆、表达并纯化了GCS（Bh），并对其进行了光谱分析。GCS（Bh）结合血红素并显示出类似肌红蛋白的光谱。这表明GCS（Bh）作为一个氧传感器，并通过一个连接的信号结构域传递构象信号，以触发嗜碱芽孢杆菌中的趋氧反应。
