Ultrafast Spectroscopy Evidence for Picosecond Ligand Exchange at the Binding Site of a Herne Protein: Heme-Based Sensor YddV
Ultrafast Spectroscopy Evidence for Picosecond Ligand Exchange at the Binding Site of a Herne Protein: Heme-Based Sensor YddV
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DOI：
10.1021/acs.jpclett.5b02517
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发表时间：
2016-01-07
影响因子：
5.7
通讯作者：
Vos, Marten H.
中科院分区：
文献类型：
--
作者：
Lambry, Jean-Christophe;Stranava, Martin;Vos, Marten H.
血红素蛋白功能的一个重要问题是蛋白质部分中存在的不同配体是否可以容易地与血红素结合的配体交换。研究血红素结构域的大肠杆菌传感器蛋白YddV的动力学NO从铁血红素解离后，通过超快光谱，我们表明，当远端血红素口袋中的疏水性亮氨酸残基突变为甘氨酸，在相当大的一部分蛋白质的水取代NO作为内部配体在一样快，类似于4 ps。这个过程，这是近无障碍，发生数量级快于相应的过程中肌红蛋白，对应于配体交换NO与血红素口袋中存在的水分子，证实了分子动力学模拟。我们的研究结果提供了重要的新的见解血红素蛋白的功能与不同的外部配体相互作用的配体交换。
An important question for the functioning of heme proteins is whether different ligands present within the protein moiety can readily exchange with heme-bound ligands. Studying the dynamics of the heme domain of the Escherichia coli sensor protein YddV upon dissociation of NO from the ferric heme by ultrafast spectroscopy, we demonstrate that when the hydrophobic leucine residue in the distal heme pocket is mutated to glycine, in a substantial fraction of the protein water replaces NO as an internal ligand in as fast as similar to 4 ps. This process, which is near-barrierless and occurs orders of magnitude faster than the corresponding process in myoglobin, corresponds to a ligand swap of NO with a water molecule present in the heme pocket, as corroborated by molecular dynamics simulations. Our findings provide important new insight into ligand exchange in heme proteins that functionally interact with different external ligands.