Wittung-Stafshede P, Gomez E, Ohman A, Aasa R, Villahermosa R M, Leckner J, Karlsson B G, Sanders D, Fee J A, Winkler J R, Malmström B G, Gray H B, Hill M G
Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Biochim Biophys Acta. 1998 Nov 10;1388(2):437-43. doi: 10.1016/s0167-4838(98)00205-2.
Electrochemical measurements show that there are high-potential states of two copper proteins, Pseudomonas aeruginosa azurin and Thermus thermophilus CuA domain; these perturbed states are formed in guanidine hydrochloride (GuHCl) solution in which the proteins are still blue (azurin) and purple (CuA). In each case, the high-potential state forms reversibly. Absorption (azurin, CuA), visible circular dichroism (azurin, CuA), resonance-Raman (CuA), and EPR (CuA) spectra indicate that the structure of the oxidized copper site of each high-potential form is very similar to that of the native protein. It is proposed that GuHCl perturbs one or more H-bonds in the blue or purple copper active site, thereby allowing Cu(I) to adopt a more favorable coordination structure than that in the rigid cavity of the native protein.
电化学测量表明，两种铜蛋白——铜绿假单胞菌天青蛋白和嗜热栖热菌CuA结构域——存在高电位状态；这些受扰状态是在盐酸胍（GuHCl）溶液中形成的，此时蛋白仍呈蓝色（天青蛋白）和紫色（CuA）。在每种情况下，高电位状态都是可逆形成的。吸收光谱（天青蛋白、CuA）、可见圆二色光谱（天青蛋白、CuA）、共振拉曼光谱（CuA）和电子顺磁共振光谱（CuA）表明，每种高电位形式的氧化态铜位点结构与天然蛋白非常相似。有人提出，GuHCl扰乱了蓝色或紫色铜活性位点中的一个或多个氢键，从而使Cu（I）能够采用比天然蛋白刚性腔中更有利的配位结构。
