Soluble guanylate cyclase is activated differently by excess NO and by YC-1: resonance Raman spectroscopic evidence.
Soluble guanylate cyclase is activated differently by excess NO and by YC-1: resonance Raman spectroscopic evidence.
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DOI：
10.1021/bi100506j
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发表时间：
2010-06-15
期刊：
影响因子：
2.9
通讯作者：
Spiro, Thomas G.
中科院分区：
文献类型：
--
作者：
Ibrahim, Mohammed;Derbyshire, Emily R.;Soldatova, Alexandra V.;Marletta, Michael A.;Spiro, Thomas G.
可溶性鸟苷酸环化酶（sGC）活性的一氧化氮（NO）的调制涉及两个不同的步骤。sGC的低水平活化是通过NO（1-NO）与血红素辅因子的化学计量结合实现的，而高得多的活化是通过在非血红素位点处结合额外的NO（xsNO）实现的。将变构激活剂YC-1添加到1-NO形式导致与xsNO状态相当的活性。在这项研究中，sGC激活的机制进行了研究，使用电子吸收和共振拉曼（RR）光谱方法。RR光谱证实，1-NO形式含有5-配位NO-血红素，并表明，添加NO到1-NO形式对光谱没有显着影响。相比之下，除了YC-1的1-NO或xsNO的形式改变RR谱显着，表明蛋白质诱导的血红素几何形状的变化。当BAY 41-2272加入到xsNO形式中时，也观察到血红素几何结构的这种变化。分配给弯曲和拉伸运动的乙烯基和丙酸酯取代基的带改变强度的图案，表明改变倾斜的吡咯环，它们所连接的。此外，N-O伸缩频率增加，而Fe-NO频率没有变化，通过DFT计算模拟的效果是由Fe-N-O角的小开口引起的。这些光谱差异证明了合成活化剂如YC-1和BAY 41-2272以及过量NO的不同活化机制。
Modulation of soluble guanylate cyclase (sGC) activity by nitric oxide (NO) involves two distinct steps. Low level activation of sGC is achieved by the stoichiometric binding of NO (1-NO) to the heme cofactor, while much higher activation is achieved by the binding of additional NO (xsNO) at a non-heme site. Addition of the allosteric activator YC-1 to the 1-NO form leads to activity comparable to xsNO state. In this study the mechanisms of sGC activation were investigated using electronic absorption and resonance Raman (RR) spectroscopic methods. RR spectroscopy confirmed that the 1-NO form contains 5-coordinate NO-heme and showed that the addition of NO to the 1-NO form has no significant effect on the spectrum. In contrast, addition of YC-1 to either the 1-NO or xsNO forms alters the RR spectrum significantly, indicating a protein-induced change in the heme geometry. This change in the heme geometry was also observed when BAY 41-2272 was added to the xsNO form. Bands assigned to bending and stretching motions of the vinyl and propionate substituents change intensity in a pattern suggesting altered tilting of the pyrrole rings to which they are attached. In addition, the N-O stretching frequency increases, with no change in the Fe-NO frequency, an effect modeled via DFT calculations as resulting from a small opening of the Fe-N-O angle. These spectral differences demonstrate different mechanisms of activation by synthetic activators, such as YC-1 and BAY 41-2272, and excess NO.
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影响因子：
2.9
作者：
Ibrahim, Mohammed;Derbyshire, Emily R.;Marletta, Michael A.;Spiro, Thomas G.
通讯作者：
Spiro, Thomas G.
影响因子：
11.4
作者：
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通讯作者：
van den Akker, Focco
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2.9
作者：
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通讯作者：
Shelnutt, JA
影响因子：
2.8
作者：
Bauernschmitt, R;Ahlrichs, R
通讯作者：
Ahlrichs, R
影响因子：
2.9
作者：
Derbyshire, Emily R.;Gunn, Alexander;Marletta, Michael A.
通讯作者：
Marletta, Michael A.