THE PHOTOSYNTHETIC CHROMATOPHORE

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 色素细胞是一种假细胞器，负责收集光和随后的转换 将光能转化为ATP形式的化学能（http：//www.ks.uiuc.edu/Research/psures）。初始激发后 通过色素细胞中的捕光蛋白的光子吸收，激发能量以 反应中心（RC）的多步过程。在RC处，激发能用于使醌分子带电， 然后通过富含蛋白质的色素细胞膜扩散到BC$_1$。在那里，带电的醌被氧化成 产生跨膜的质子梯度，这反过来又驱动ATP合成酶产生ATP。在紫色细菌中， 例如球形红细菌，负责光子捕获的蛋白质被称为光捕获复合物1 (LH1)和捕光复合物2（LH 2）。LH 1与色素细胞中发现的另外两种蛋白质RC和 PufX，以形成LH 1-RC-PufX二聚体复合物。LH 2和LH 1-RC-PufX具有双重功能;它们不仅负责 捕获光能，它们还诱导膜弯曲以使色素细胞成形为，例如，囊泡或管。 因此，该系统与理解生物物理学中的两个基本问题有关，即膜 形态发生和细胞能量产生。

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. The chromatophore is a pseudo-organelle that is responsible for harvesting light and subsequent conversion of light energy to chemical energy in the form of ATP (http://www.ks.uiuc.edu/Research/psures). After initial excitation from photon absorption by the light harvesting proteins in the chromatophore, excitation energy is tranferred in a multi-step process to a reaction center (RC). At the RC the excitation energy is used to charge a quinone molecule, which then diffuses through the protein-rich chromatophore membrane to a bc$_1$. There the charged quinone is oxidized yo produce a proton gradient across the membrane, which in turn drives ATP production by ATP synthase. In purple bacteria, such as Rhodobacter sphaeroides, the protein responsible for photon capture are known as light harvesting complex 1 (LH1) and light harvesting complex 2 (LH2). LH1 associates with two other proteins found in the chromatophore, RC and PufX, to form LH1-RC-PufX dimer complexes. LH2 and LH1-RC-PufX have a dual function; not only are they responsible for capturing light energy, they also induce membrane curvature to shape the chromatophore into, e.g., vesicles or tubes. Therefore, the systemis relevant to understand two fundamental questions in biophysics, namely membrane morphonegensis and cellular energy production.