Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
J Phys Chem B. 2010 Mar 4;114(8):2938-43. doi: 10.1021/jp909425z.
Isolating elemental steps that comprise a protein reaction in solution is a difficult process. In this study, the use of sugar-derived glass matrices is evaluated as a biophysical tool to help dissect out elemental steps and isolate intermediates. Two features of the glass are utilized in this endeavor: (i) the capacity of trehalose glass matrices to support thermal reduction over macroscopic distances; and (ii) the ability of glass matrices to significantly damp large amplitude protein dynamics. The focus of the study is on the reaction of nitric oxide (NO) with a nitrite ion coordinated to the heme iron of hemoglobin (Hb). The thermal reduction property of the glass is used to generate NO from nitrite within the glass, and the damping of protein dynamics is used to control entry of NO into the distal heme pocket of Hb, where it can either interact with bound nitrite or bind to the heme iron. The results not only relate to earlier controversial studies addressing the reactions of Hb with NO and nitrite but also raise the prospect that these properties of sugar-derived glassy matrices can be exploited as a new biophysical tool to modulate and probe reactions of NO with hemeproteins as well as a wide range of other metalloproteins.
在溶液中分离构成蛋白质反应的基本步骤是一个困难的过程。在这项研究中，评估了糖衍生的玻璃基质作为一种生物物理工具的用途，以帮助剖析基本步骤并分离中间产物。该玻璃具有两个特点，在这项研究中得到了利用：（i）海藻糖玻璃基质在宏观距离上支持热还原的能力；（ii）玻璃基质显著抑制大振幅蛋白质动力学的能力。该研究的重点是一氧化氮（NO）与血红蛋白（Hb）的血红素铁配位的亚硝酸盐离子的反应。玻璃的热还原特性用于在玻璃内从亚硝酸盐生成 NO，并且蛋白质动力学的阻尼用于控制 NO 进入 Hb 的远端血红素口袋，在那里它可以与结合的亚硝酸盐相互作用或与血红素铁结合。研究结果不仅与早期有关 Hb 与 NO 和亚硝酸盐反应的有争议的研究有关，而且还提出了这样一种可能性，即这些糖衍生的玻璃基质的特性可以被用作一种新的生物物理工具，以调节和探测 NO 与血红素蛋白以及广泛的其他金属蛋白的反应。
