STRUCT OF YEAST GUANYLATE KINASE COMPLEXED W/BISUBSTRATE MIMICKING INHIBITOR

与双底物模拟抑制剂复合的酵母鸟苷酸激酶的结构

• 批准号: 6205773
• 负责人: HONGGAO YAN
• 金额: --
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6205773
• 关键词: biological products; biomedical resource; proteins; spectrometry

Metal-substituted hemeproteins are an excellent means of studying the role of the heme iron in oxygen-binding and release. When the iron center in myoglobin is replaced by cobalt, cobalt-substituted myoglobin has been shown to reversibly bind oxygen. However, the oxygen affinity for cobaltous myoglobin (CoMb) is lower than ferrous myoglobin (Mb). EPR studies on CoMb have shown that, unlike native Mb where deoxy Mb is high spin (S=2) and oxy Mb is low spin (S=0), the oxy- and deoxy- states of CoMb are both low spin (S==). This implies structural/electronic differences in the deoxy- states of the two species, which may contribute to the lower oxygen affinity for CoMb. At Beamline U4B, we have obtained the L-edge spectra of cobaltous myoglobin in the oxy- and deoxy- states. The experimental data demonstrate that the L-edge spectra of Deoxy CoMb and Oxy CoMb are noticeably different, corresponding to differences cobalt oxidation states and site symmetries between these two species. In the future, we will examine the Oxy CoMb photoproduct, which is generated by photolysis of Oxy CoMb at 15 K, and has been shown to be electronically different than deoxy CoMb by EPR. Finally, we will continue to examine cobaltous heme model compounds in order to assist in our multiplet simulations of the protein species.

金属取代血红素蛋白是研究 血红素铁在氧结合和释放中的作用。 当 肌红蛋白中的铁中心被钴取代， 肌红蛋白已经显示出可逆地结合氧。 但 钴肌红蛋白（CoMb）的氧亲和力低于亚铁 肌红蛋白（Mb）。 对CoMb的EPR研究表明，与天然Mb不同， 其中脱氧Mb是高自旋（S=2）并且氧基Mb是低自旋（S=0）， CoMb的氧化态和脱氧态都是低自旋态（S==）。 这意味 这两种物质的脱氧态的结构/电子差异 物种，这可能有助于降低CoMb的氧亲和力。 在U4 B光束线上，我们获得了钴的L边光谱 氧和脱氧状态的肌红蛋白。 实验数据 证明了脱氧CoMb和氧合CoMb的L边光谱是 明显不同，对应于钴氧化的差异 这两个物种之间的状态和位置对称性。 在未来， 我们将研究氧钴Mb的光产物，它是由 在15 K下，氧钴Mb的光解，并已被证明是 电子上不同于脱氧CoMb。 最后我们将 继续研究钴血红素模型化合物，以帮助 我们对蛋白质的多重态模拟。