Nitric Oxide Activation of Guanylate Cyclase Pushes the α1 Signaling Helix and the β1 Heme-binding Domain Closer to the Substrate-binding Site
Nitric Oxide Activation of Guanylate Cyclase Pushes the α1 Signaling Helix and the β1 Heme-binding Domain Closer to the Substrate-binding Site
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DOI：
10.1074/jbc.m113.504472
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发表时间：
2014-01-03
影响因子：
4.8
通讯作者：
Behrends, Soenke
中科院分区：
文献类型：
--
作者：
Busker, Mareike;Neidhardt, Inga;Behrends, Soenke
组装结构域的一氧化氮敏感的鸟苷酸环化酶（NOsGC）的完整结构仍有待确定。还不知道NO与鸟苷酸环化酶中血红素的结合如何传递到催化结构域。在本研究中，鸟苷酸环化酶的构象变化的激活NO的研究使用FRET。内源性色氨酸残基用作供体，底物类似物2-Mant-3-dGTP用作受体。该酶含有五个色氨酸残基，均匀分布在所有四个功能域。这提供了一个独特的机会来检测功能结构域相对于底物结合催化区的移动。FRET测量表明NO使（1）血红素NO结合结构域的B螺旋中的色氨酸22和（1）卷曲螺旋结构域的第二短螺旋中的色氨酸466更靠近催化结构域。我们建议，各自的域作为一对钳子迫使催化域的一氧化氮活化构象。
The complete structure of the assembled domains of nitric oxide-sensitive guanylate cyclase (NOsGC) remains to be determined. It is also unknown how binding of NO to heme in guanylate cyclase is communicated to the catalytic domain. In the current study the conformational change of guanylate cyclase on activation by NO was studied using FRET. Endogenous tryptophan residues were used as donors, the substrate analog 2-Mant-3-dGTP as acceptor. The enzyme contains five tryptophan residues distributed evenly over all four functional domains. This provides a unique opportunity to detect the movement of the functional domains relative to the substrate-binding catalytic region. FRET measurements indicate that NO brings tryptophan 22 in the B helix of the (1) heme NO binding domain and tryptophan 466 in the second short helix of the (1) coiled-coil domain closer to the catalytic domain. We propose that the respective domains act as a pair of tongs forcing the catalytic domain into the nitric oxide-activated conformation.