PROBING THE SEC-LIKE THYLAKOID PROTEIN IMPORT PATHWAY

信号识别、信号转导、蛋白质跨膜转运 细胞膜、能量转导和蛋白质折叠是生物学的主要领域。 自从我们了解传染病以来， 细胞生长和死亡取决于对这些现象的理解。 对所有这些研究领域的贡献可以通过学习 蛋白质真实的实时输入叶绿体类囊体。 近日更 清楚地发现类囊体蛋白输入途径之一是相似的 原核（大肠杆菌）蛋白分泌途径， 涉及至少七种Sec蛋白质 这种Sec样类囊体导入 途径被认为是内共生起源的直接结果， 来自一个祖先蓝藻的叶绿体。 在这项研究中， 在这里，前体蛋白与Sec样类囊体的相互作用 进口仪器将用荧光、自旋标记 光敏探针连接到核糖体结合的前体的不同 长度 此外，导入全长探针标记的前体 将由光产生的跨膜质子动力引发 并且输入过程将被真实的时间监测（停流状态） 使用荧光和/或电子顺磁共振光谱法。 从中断的进口实验（核糖体- 结合的前体）有助于解释真实的时间 测量. 这些类囊体蛋白的研究将有助于 直接影响我们对原核蛋白分泌的理解。

Signal recognition, signal transduction, protein translocation across membranes, energy transduction and protein folding are major areas of investigation in biology since our understanding of infectious diseases and cell growth and death is dependent upon a comprehension of these phenomena. Contributions to all of these fields of research can be made by studying protein import into chloroplast thylakoids in real time. Recently, it has become clear that one of the thylakoid protein import pathways is similar to the prokarotic (Escherichia coli) protein secretion pathway which involves at least seven "Sec" proteins. This Sec like thylakoid import pathway is thought to be a direct result of the endosymbiotic origin of chloroplasts from an ancestral cyanobacterium. In the research proposed here, the interactions of a precursor protein with the Sec-like thylakoid import apparatus will be investigated with fluorescent, spin-labeled, and photoactive probes attached to ribosome-bound precursors of different lengths. In addition, the import of a full-length, probe-labeled precursor will be initiated by photoproduction of a transmembrane proton motive force and the import process will be monitored in real time (stopped-flow regime) using fluorescence and/or electron paramagnetic resonance spectroscopy. Spectral dat gathered from the interrupted import experiments (ribosome- bound precursors) are expected to aid in interpretation of the real time measurements. These investigations of thylakoid protein import will directly influence our understanding of prokaryotic protein secretion.