IDENTIFICATION OF SULFUR OXIDATION IN BIOLOGICAL SYSTEMS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们建议使用硫的x射线吸收边缘来跟踪两个系统中硫的生理上重要的氧化：1)叶绿体中小热休克蛋白中蛋氨酸残基的氧化；2)半胱氨酸脱硫酶中Fe-S簇组装过程中产生的过硫中间体。对于第一个系统，我们有初步的XAS测量表明，蛋氨酸氧化发生在体内，以响应热应激和叶绿体小热休克蛋白（cHsp）的过量生产。我们希望用更好的信号噪声来改进这些测量，并将这些研究扩展到包括氧化应激恢复的过程。对于第二个系统，我们已经验证了使用快速酸淬样品进行硫XAS的有效性。现在我们将着重于对冷冻过硫化物中间体进行测量。第二个项目的长期目标是使用硫XANES动态监测硫进入产品Fe-S簇的情况。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose to use sulfur x-ray absorption edges to track physiologically significant oxidation of sulfur in two systems 1) the oxidation of methionine residues in the small heat shock protein from chloroplasts and 2) the persulfide intermediate generated during Fe-S cluster assembly in the enzyme cysteine desulfurase. For the first system, we have initial XAS measurements indicating that methionine oxidation occurs in vivo in response to heat stress and overproduction of the chloroplast small heatshock protein (cHsp). We would like to improve these measurements with better signal to noise and to extend these studies to include the process of recovery from oxidative stress. For the second system, we have already verified the validity of using rapid acid quenched samples for sulfur XAS. We will now focus on making measurements of the frozen persulfide intermediate. The long term goal of the second project is to kinetically monitor the insertion of sulfur into the product Fe-S cluster using sulfur XANES.