COORDINATION OF CO (II) PROTOPORPHYRIN SUBSTITUTED HEMOPROTEINS

CO (II) 原卟啉取代的血蛋白的配位

• 批准号: 6120382
• 负责人: CAROLINE CAROLINE LEE
• 金额: --
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 1999-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6120382
• 关键词: biological products; biomedical resource; cardiovascular system; proteins; spectrometry

Investigations of Co(III) porphyrin complexes have in part been motivated by their use as models for cobalamin species such as coenzyme B12, and in part by their reactivity with nucleic acids. Interactions of Co(III) porphyrins with biomolecules are governed by their axial ligations and no Co(III) porphyrin complex with a single strong field, s-donating axial ligand, such as nitrogen, has been reported. Unlike Co(III) porphyrins, pentacoordinate Fe(III) porhyrins are found in many hemoproteins and have also been synthesized. For example, the met (oxidized, ferric) form of the is64 to Leu mutant of the oxygen-carrying protein myoglobin [Mb(H64L)] contains a pentacoordinate metal with an axial histidine ligand, whereas in the native protein, the second axial ligand is a water molecule. No water molecule was found near the metal in the mutant. In this study, Co(III) protoporphyrin-substituted Mb and Mb(H64L) are studied by x-ray absorption spectroscopy. The absorption edge energy for both proteins occur near 7729 eV, suggesting that both Hare hexacoordinate. The sixth ligand of Co(III)-substituted Mb has Hbeen suggested to be His64, rather than water as in the Fe(III) protein. Since neither His64 nor water (presumably) are present in the Co(III)-substituted mutant, the current results are surprising. Further studies are being conducted to identify the sixth ligand in Co(III) Mb(H64L).

钴(III)-卟啉络合物的部分研究 其动机是将它们用作钴胺物种的模型 辅酶B12，部分是由于它们与核酸的反应。 钴(III)卟啉与生物分子的相互作用受 它们的轴向连接和无钴(III)卟啉配合物与单一的 强场，S捐献的轴向配体，如氮，已被 据报道。与Co(III)不同，五配位Fe(III) 在许多血液蛋白中发现了卟啉，也被认为是 合成的。例如，MET(氧化铁)形式的IS64 携带氧蛋白肌红蛋白的亮氨酸突变体[Mb(H64L)] 含有一个带有轴向组氨酸配体的五配位金属， 而在天然蛋白质中，第二轴向配体是水 分子。在突变体的金属附近没有发现水分子。 在本研究中，Co(III)原卟啉取代的Mb和Mb(H64L)是 用X-射线吸收光谱进行了研究。吸收边能量 这两种蛋白质都出现在7729 eV附近，这表明两种蛋白质都是 六纵坐标。Co(III)取代的Mb的第六个配体已被取代 建议是His64，而不是铁(III)蛋白中的水。 由于His64和水(可能)都不存在于 CO(III)-取代突变体，目前的结果令人惊讶。 目前正在进行进一步的研究，以确定 CO(III)Mb(H64L)。