ELECTRON DENSITY MAPPING OF IRON PORPHYRINS

铁卟啉的电子密度图

• 批准号: 3337440
• 负责人: PHILIP COPPENS
• 金额: $ 6.9万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-07-01 至 1986-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3337440
• 关键词: X ray crystallography; chemical group; chemical models; cobalt; electron density; iron; ligands; metalloporphyrins; oxygen transport; porphyrin structure

Accurate crystallographic methods developed over the last decade are to be applied in the mapping of the three dimensional electron density distribution of iron porphyrins. The compounds selected are models for the prosthetic group of oxygen-transport and electron-transfer hemoproteins, and represent different oxidation states spin states and coordination numbers. In addition to increasing our fundamental knowledge of the active site of the hemoproteins the experimental electron density distribution will answer a number of specific questions related to the extent to which changes in electronic structure of the heme contribute to the cooperativity mechanism for loading and unloading of oxygen. Differences in radial dependence of the transition metal electron distribution and the nature of the bonding between metal and ligands will be analyzed. Knowledge of the electronic structure of the porphyrin ligand will provide basic information which can be applied to the larger number of other biological systems in which porphyrin complexes participate. The experimental electron density distribution will serve in the interpretation of the large body of physico-chemical data collected in recent years. The research will be performed mainly on automated low temperature diffraction equipment in the principal investigators laboratory. Use will be made of an extensive library of locally developed programs for charge density analysis by diffraction methods. In a later stage part of the measurements will make use of the SUNY beamline at the National Synchrotron Light Source at Brookhaven National Laboratory which is to become operational during 1983.

精确的晶体学方法在过去十年中发展起来