TIME-RESOLVED MAGNETIC CIRCULAR DICHROISM

描述：时间分辨磁循环的开发和使用 二色性光谱（TRMCD）。 的应用 磁场诱导手性，并且观察到的信号通常是 定位于被探测吸收的部分。 这 技术用于血红素中心。将技术扩展到 近紫外线是要开发，和初步数据的静态MCD的 色氨酸是令人鼓舞的（将需要一个额外的电磁铁， 补偿单元窗口的法拉第旋转）。 中央 想法是光解配体，然后研究动力学。 的 TRMCD装置在血红素中心的分辨率约为50-100 ns 吸收（部分由蛋白质产生的信号复杂化） 扩散重定向时间，约100 ns-这种并发症已经 分析并可能纠正）。 细胞色素氧化酶的研究， 细胞色素C3和细胞色素C'正在进行中。 一个特别重要 过去一段时间的发现是在 细胞色素氧化酶的细胞色素a3位点，导致部分模型 门控机制的耦合能量释放氧还原， 质子泵（配体穿梭模型）。一种未知的配体 蛋白质与蛋白质铁中心结合， 用这种技术。 未来最有趣的研究集中在 血红蛋白和R到T变构转换，如果色氨酸残基可以 隔离和测量。静态MCD显示了一些希望 在溶液中的色氨酸。突变体应该分离出哪个trp残基产生 信号了最近的TRCD结果，刚刚提交给生物化学， 令人兴奋.杰出的研究，除了有两个问题， 上一篇：蛋白质取向弛豫问题， 在100 ns的时间尺度上，以及生产率的问题。

DESCRIPTION: Development and use of time resolved magnetic circular dichroism spectroscopy (TRMCD) is proposed. The application of a magnetic field induces chirality and the observed signal is generally localized to the moiety who's absorption is being probed. This technique is used for heme centers. Extension of the technique to the near UV is to be developed, and preliminary data on the static MCD of tryptophan is encouraging (will require an extra electromagnet to compensate for the Faraday rotation of the cell windows). The central idea is to photolyze a ligand and then study the kinetics. The resolution of the TRMCD apparatus is about 50-100 ns in the heme center absorption (partly complicated by signals that result from the protein diffusional reorientation time, about 100 ns- this complication has been analyzed and is probably correctable). Studies on cytochrome oxidase, cytochrome c3, and cytochrome c' are ongoing. A particularly important finding of the past period was the finding of a transient ligation at the cytochrome a3 site of cytochrome oxidase, resulting in a model for part of the gating mechanism coupling energy release by oxygen reduction to proton pumping (the ligand shuttle model). An unknown ligand in the protein binds to the protein iron center and this has been best studied with this technique. Most interesting future studies center on hemoglobin and the R to T allosteric transition, if the trp residues can be isolated and measured. Some hope has been demonstrated by static MCD on trp in solution. Mutants should isolate which trp residues yield signal. Recent TRCD results, just submitted to Biochemistry, are exciting. Outstanding studies except there were two problems cited in last review: the problem of protein orientational relaxation, which is on the 100 ns time scale, and the issue of productivity.