HIGH FREQUENCY CRYOGENIC EPR STUDY OF METHYLMALONYL COA MUTASE ENZYME

甲基丙二酰辅酶A变位酶的高频低温EPR研究

• 批准号: 6120694
• 负责人: RUMA V BANERJEE
• 金额: $ 0.11万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-15 至 1999-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6120694
• 关键词: bacteria; biomedical resource; enzymes

X-band EPR studies on methylmalonyl-CoA mutase in Prof. Banerjee's laboratory show rather messy-looking spectra that seems to represent contributions from two separate species (JBC, 1995, 270:9295; JACS, 1995, 117:7033). This system requires additional information for a definitive interpretation. The Banerjee group has between 60 and 80 uM spin associated with the catalytic intermediate, which has a crossover g value at 2.11. By selective isotope substitution studies, the signals are deduced to show a biradical intermediate which has an exchange coupled Co(II)-organic radical pair. This is a steady-state sample, and they have never been able to get more than 0.4 spin/mol of enzyme. High-field EPR is being undertaken with the hope that we can separate the signals and eventually simulate the spectra. Sample handling is challenging, as the enzyme must be handled anaerobically prior to freezing, and the capillary sample tubes are difficult to load, ship, preserve in frozen state, and load ed into the spectrometer without thawing or contamination. Nevertheless, progress is being made, and preliminary Q-band and W-band spectra have been obtained at the IERC. This project will continue in 1998.

甲基丙二酰辅酶a突变酶的x波段EPR研究。