Randall Division of Cell and Molecular Biophysics, School of Physical Sciences & Engineering, King's College, London, United Kingdom.
Biophys J. 2010 Dec 1;99(11):3716-25. doi: 10.1016/j.bpj.2010.09.008.
Activation of the multicomponent enzyme NADPH oxidase requires the interaction between the tandem SH3 domain of the cytosolic subunit p47(phox) and the cytoplasmic tail of membrane-bound p22(phox). In the resting state, p47(phox) exists in an autoinhibited conformation stabilized by intramolecular contacts between the SH3 domains and an adjacent polybasic region. Phosphorylation of three serine residues, Ser(303), Ser(304), and Ser(328) within this polybasic region has been shown to be sufficient for the disruption of the intramolecular interactions thereby inducing an active state of p47(phox). This active conformation is accessible to the cytoplasmic tail of p22(phox) and initiates the formation of the membrane-bound functional enzyme complex. Molecular dynamics simulations reveal insights in the mechanism of activation of the autoinhibited form of p47(phox) by in silico phosphorylation, of the three serine residues, Ser(303), Ser(304), and Ser(328). The simulations highlight the major collective coordinates generating the opening and the closing of the two SH3 domains and the residues that cause the unmasking of the p22(phox) binding site.
多组分酶 NADPH 氧化酶的激活需要细胞溶质亚基 p47(phox)的串联 SH3 结构域与膜结合的 p22(phox)的细胞质尾巴之间的相互作用。在静止状态下，p47(phox)存在于自抑制构象中，该构象由 SH3 结构域之间的分子内接触和相邻的多碱性区域稳定。已经表明，该多碱性区域内三个丝氨酸残基（Ser(303)、Ser(304)和 Ser(328)）的磷酸化足以破坏分子内相互作用，从而诱导 p47(phox)的活性状态。这种活性构象可与 p22(phox)的细胞质尾巴接触，并启动膜结合功能酶复合物的形成。分子动力学模拟揭示了 p47(phox)的自抑制形式通过模拟磷酸化 Ser(303)、Ser(304)和 Ser(328)这三个丝氨酸残基的激活机制的见解。模拟突出了产生两个 SH3 结构域的打开和关闭的主要集体坐标，以及导致 p22(phox)结合位点暴露的残基。
