论文标题
S-亚硝基化肌红蛋白的光谱，动力学和水合
Spectroscopy, Dynamics and Hydration of S-Nitrosylated Myoglobin
论文作者
论文摘要
S-亚硝基化是半胱氨酸硫醇侧链的共价添加，是一种重要的经际修饰，可以改变各种蛋白质的功能。研究了甲基限制的半胱氨酸模型系统和肌红蛋白，研究了凝结相中S-硝基化的结构动力学和振动光谱。使用传统的点电荷和-sno组的物理上更真实的多极力场，发现可以找到Sn-和Nottretch以及SNO弯曲的振动，并与其他蛋白质模式进行区分，以在50 K处模拟MBSNO的其他蛋白质模式。发现稳定的顺式和Trans-MBSNO的发现与其他protecoin是一致的 - 与其他pretecoin相符。对于MBSNO，在$ \ sim 3 $Å\/中，观察到的EF循环的搬迁与可用的X射线结构一致，并且-sno标签所采用的构象与X射线结构良好一致。尽管-SNO组的大小较大，但由于静电较强，MBSNO被发现招募了比WT MB的10Å\/以内的更多水分子。同样，在比较A-和H螺旋之间的水合时，它们在WT和MBSNO之间的水平差异高达30 \％。这表明局部水合也可以通过亚硝基化显着调节。
S-nitrosylation, the covalent addition of NO to the thiol side chain of cysteine, is an important post-transitional modification that can alter the function of various proteins. The structural dynamics and vibrational spectroscopy of S-nitrosylation in the condensed phase is investigated for the methyl-capped cysteine model system and for myoglobin. Using conventional point charge and physically more realistic multipolar force fields for the -SNO group it is found that the SN- and NO-stretch and the SNO-bend vibrations can be located and distinguished from the other protein modes for simulations of MbSNO at 50 K. The finding of stable cis- and trans-MbSNO is consistent with experiments on other proteins as is the observation of buried -SNO. For MbSNO the observed relocation of the EF loop in the simulations by $\sim 3$ Å\/ is consistent with the available X-ray structure and the conformations adopted by the -SNO label are in good overall agreement with the X-ray structure. Despite the larger size of the -SNO group, MbSNO is found to recruit more water molecules within 10 Å\/ of the modification site than WT Mb due to the stronger electrostatics. Similarly, when comparing the hydration between the A- and H-helices they differ by up to 30 \% between WT and MbSNO. This suggests that local hydration can also be significantly modulated through nitrosylation.
