Biophysical Studies of Metalloenzymes

本研究的目的是进一步开发一种独特的多频能力，以执行和分析先进的顺磁共振（amr）光谱（电子-核双共振，endor；电子自旋-回波包络调制，em），作为x射线晶体学的强大，选择性和敏感的盟友，用于表征金属酶活性位点及其与底物/抑制剂/产物的相互作用，无论是在静息状态还是在关键中间体中。金属酶的amr研究将着重于三个方面：(I)具有高自旋（s1）的整数自旋系统的amr，但其表现出epr活性，基态Non-Kramers双重态；（II）底物和抑制剂与氮酶MoFe蛋白的钼铁辅因子的相互作用；(3)热自养甲烷菌甲基辅酶M还原酶（MCR）产甲烷的机理。金属离子在生物学中无处不在；不少于三分之一的蛋白质和酶需要金属离子作为辅助因子。该计划旨在开发和应用先进的顺磁共振（amr）光谱作为x射线晶体学的强大，选择性和敏感的盟友，用于表征金属酶活性位点及其与底物的相互作用，无论是在静息状态还是在关键中间体中。除了开发新方法外，该项目还从事环境和农业上重要的酶——氮酶的研究，并研究从热自养甲烷杆菌中分离出来的一种细菌酶——甲基辅酶M还原酶产生温室气体甲烷的过程。

HoffmanMCB 9904018The objective of this research is to further develop a unique multifrequency capacity to perform and analyze advanced paramagnetic resonance (amr) spectroscopies (electron-nuclear double resonance, endor; electron spin-echo envelope modulation, eseem) as a powerful, selective, and sensitive ally to X-ray crystallography for characterizing metalloenzyme active sites and their interactions with substrates/inhibitors/products, both in the resting state and in key intermediates. The amr studies of metalloenzymes will emphasize three areas: (I) The amr of integer-spin, systems with high spin (S 1), but which exhibit an epr-active, ground-state Non-Kramers doublet; (II) Substrate and inhibitor interactions with the molybdenum-iron cofactor of the nitrogenase MoFe protein; and (III) The mechanism of methane production by Methyl-coenzyme M reductase (MCR) isolated from Methanobacterium thermoautotrophicum. Metal ions are pervasive in biology; no less than one-third of all proteins and enzymes require metal ions as cofactors. This program seeks to develop and apply advanced paramagnetic resonance (amr) spectroscopies as a powerful, selective, and sensitive ally to X-ray crystallography for characterizing metalloenzyme active sites and their interactions with substrates, both in the resting state and in key intermediates. In addition to the development of new methodologies, this program is engaged in the study of the environmentally and agriculturally important enzyme, nitrogenase, and in the study of the production of the greenhouse gas, methane, by a bacterial enzyme, Methyl-coenzyme M reductase, isolated from Methanobacterium thermoautotrophicum.