Molecular oxygen regulates the enzymatic activity of a heme-containing diguanylate cyclase (HemDGC) for the synthesis of cyclic di-GMP.
Molecular oxygen regulates the enzymatic activity of a heme-containing diguanylate cyclase (HemDGC) for the synthesis of cyclic di-GMP.
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DOI：
10.1016/j.bbapap.2009.09.028
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
H. Sawai;S. Yoshioka;T. Uchida;M. Hyodo;Y. Hayakawa;K. Ishimori;S. Aono
中科院分区：
文献类型：
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作者：
H. Sawai;S. Yoshioka;T. Uchida;M. Hyodo;Y. Hayakawa;K. Ishimori;S. Aono
我们研究了一种专性厌氧细菌Desulfotalea psychrophila的二胍酸环化酶的结构和酶学性质，该酶由n端传感器结构域和c端二胍酸环化酶结构域组成。传感器结构域的氨基酸序列同源性和光谱特性与含有原血红素的珠蛋白偶联传感器蛋白的传感器结构域相似。这种含血红素的二胍酸环化酶只有在传感区域的血红素与分子氧结合时才能催化GTP形成环二gmp。当血红素以铁、脱氧、co结合或no结合形式存在时，没有观察到酶活性。共振拉曼光谱显示，Tyr55与血红素结合的O2形成氢键，而不是与CO形成氢键。相反，Gln81与血红素结合的CO相互作用。这些氢键网络的差异将对负责调节酶活性的选择性O2感知起关键作用。
We have studied the structural and enzymatic properties of a diguanylate cyclase from an obligatory anaerobic bacterium Desulfotalea psychrophila, which consists of the N-terminal sensor domain and the C-terminal diguanylate cyclase domain. The sensor domain shows an amino acid sequence homology and spectroscopic properties similar to those of the sensor domains of the globin-coupled sensor proteins containing a protoheme. This heme-containing diguanylate cyclase catalyzes the formation of cyclic di-GMP from GTP only when the heme in the sensor domain binds molecular oxygen. When the heme is in the ferric, deoxy, CO-bound, or NO-bound forms, no enzymatic activity is observed. Resonance Raman spectroscopy reveals that Tyr55 forms a hydrogen bond with the heme-bound O2, but not with CO. Instead, Gln81 interacts with the heme-bound CO. These differences of a hydrogen bonding network will play a crucial role for the selective O2sensing responsible for the regulation of the enzymatic activity.