Alter G M
J Biol Chem. 1983 Dec 25;258(24):14960-5.
In an effort to examine the consequences of phase state changes on protein structures, optical absorption spectra of several bovine hemoglobin derivatives in lyophilized, ammonium sulfate-precipitated, and crystalline states were examined. Absorption spectra were used to compare protein conformations. Differences between solution and several solid state spectra were apparent. They were greatest for lyophilized preparations, were inhibited by ligand binding, the tightest binding ligand being the most effective inhibitor, and were substantially or totally reversible upon dissolving the solid state protein. Though the magnitude of spectral changes varied, they all indicated characteristically different proportions of the protein were converted to a reversible hemichrome in each type of solid state preparation. The extent of hemichrome formation was correlated with the degree to which the protein tends to be dehydrated in each solid state preparation. This may reflect the role of water in determining the three-dimensional structure of hemoglobin. Absorption spectra of solid state hemoglobin preparations were obtained from photoacoustic spectra using a novel method for spectral analysis. Results presented here demonstrate the utility of this procedure in probing structures of solid state proteins.
为了研究相态变化对蛋白质结构的影响，我们检测了几种处于冻干态、硫酸铵沉淀态和结晶态的牛血红蛋白衍生物的光吸收光谱。利用吸收光谱来比较蛋白质的构象。溶液光谱与几种固态光谱之间的差异很明显。冻干制剂的差异最大，配体结合可抑制这种差异，结合最紧密的配体是最有效的抑制剂，并且在固态蛋白质溶解后，差异基本或完全可逆。尽管光谱变化的幅度有所不同，但它们都表明在每种固态制剂中，蛋白质转化为可逆半色蛋白的比例具有特征性差异。半色蛋白的形成程度与每种固态制剂中蛋白质脱水的程度相关。这可能反映了水在决定血红蛋白三维结构中的作用。固态血红蛋白制剂的吸收光谱是使用一种新颖的光谱分析方法从光声光谱中获得的。此处呈现的结果证明了该方法在探测固态蛋白质结构方面的实用性。
