SPECTROSCOPY OF AN ENGINEERED PURPLE CU(A) CENTER IN AZURIN

天蓝色工程紫色 CU(A) 中心的光谱

• 批准号: 6118840
• 负责人: YI LU
• 金额: $ 0.1万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6118840
• 关键词: bioengineering /biomedical engineering; biological products; biomaterials; biomedical resource; enzymes; proteins

Spectroscopic characterization of a purple Cu(A) center engineered into the blue copper protein azurin from Pseudomonas aeruginosa (called purple Cu(A) azurin hereafter is presented. Both electrospray mass spectrometry and copper analysis indicated the protein binds two copper ions per protein. The electronic absorption (UV-vis), magnetic circular dichroism (MCS), multifrequency electron paramagnetic resonance (EPR), and X-ray absorption (XAS) spectra of the purple Cu(A) azurin are strikingly similar to other native or engineered Cu(A) center, indicating that they all share similar geometric and electronic structures. Multifrequency EPR spectra show a well-resolved seven-line hyperfine structure in the g(parallel) region, typical of a delocalized mixed-valence [Cu(1.5)???Cu(1.5)] binuclear center. Compared with other delocalized mixed-valence Cu(A) centers, this purple Cu(A) azurin has a relatively high energy near-IR CuBCu absorption at 770nm, the largest A(paralle l) a t 55 G, and the shortest CuBCu distance at 2.39A. These results may reflect a more sterically compressed Cu(A) center in azurin, perhaps as the result of forcing the normally mononuclear blue copper center in azurin to accept a binuclear Cu(A) center, and are consistent with the general trend between the near-IR CuBCu absorption and the degree of Cu2[SR]2 core contraction.

紫色Cu（A）中心的光谱表征 铜绿假单胞菌的蓝铜蛋白天青 （以下称为紫Cu（A）天青蛋白。 两种电喷雾 质谱和铜分析表明，蛋白质结合两个 铜离子/蛋白质。 电子吸收（UV-vis），磁性 圆二色性（MCS），多频电子顺磁 的共振（EPR）和X射线吸收（XAS）光谱。 Cu（A）天青蛋白与其他天然或工程化的 Cu（A）中心，表明它们都具有相似的几何形状和 电子结构。 多频EPR谱表明， 在g中的良好分辨的七线超精细结构（平行） 区域，典型的离域混合价态[Cu（1.5）？铜（1.5）] 双核中心 与其他离域混合价态Cu（A）相比 中心，这种紫色Cu（A）天青具有相对较高的近红外能量 CuBCu在770 nm处的吸收，最大A（λ 1）为55 G， 最短CuBCu距离为2.39A。 这些结果可能反映了一个更 空间压缩的Cu（A）中心在天青蛋白，可能是由于 迫使天青蛋白中通常为单核的蓝铜中心 接受双核Cu（A）中心，并且与一般的 近红外CuBCu吸收与Cu 2 [SR]2程度之间的趋势 核心收缩