PHOTOSYNTHETIC REACTION CENTER MAQUETTE

Maquetes是基于蛋白质的简化合成版本 结构。多肽从头合成的研究进展 构建化学简单的多肽的机会 生物氧化还原位点，允许我们查看分子 工程涉及到他们的组装和建立最低限度的 对其高度复杂的自然功能的要求 对口单位。[cpp-？2]2蛋白(cpp=共卟啉I，？= CGGGELWKLHEELLKKFEELL-KLHEERLKKL-CONH2)是用于 光合作用反应中心(PRC)，由四个相同的 两栖的？-带有CPP二聚体单元的螺旋 N端。它是基于我们以前的工作(自然368， 425-432,1994)，并且能够结合最多四个血红素单元。二聚体 在中国，卟啉模拟特殊的配对，而bis-His结合 血红素是BCHL和BPH的典范。我们正在调查 [CPP-？2]2在缓冲溶液中的荧光发射性质 其荧光寿命为12.0 ns，峰值各向异性为0.06， 转动相关时间为5.2 ns(ex=398 nm，em=620 nm)。 相反，缓冲液中游离CCP表现出荧光发射5 寿命为15.5 ns(与[CPP-？2]2的外径相同)的倍数 (长30%)，峰值各向异性为0.14，旋转 相关时间为0.083 ns。这些结果表明，我们是 实际上，测量结合在多肽上的CPP的发射，我们可以 估计分子直径为36E，呈球形。

Maquettes are simplified synthetic versions of protein based structures. Progress with de novo synthesis of peptides presents the opportunity to construct chemically simple peptides that incorporate biological redox sites, permitting us to view the molecular engineering involved in their assembly and to establish the minimal requirements for function of their highly complex natural counterparts. [CPP-?2]2 protein (CPP = coproporphyrin I, ? = CGGGELWKLHEELLKKFEELL-KLHEERLKKL-CONH2) is a maquette for the Photosynthetic Reaction Center (PRC) and consist of four identical amphipatic ?-helixes with a CPP dimeric unit appended covalently to the N terminus. It is based in our previous work (Nature 368, 425-432, 1994) and is able to bind up to four heme units. The dimeric porphyrin mimics the special pair in the PRC whereas the bis-His bound hemes are a model for Bchl and Bph. We are investigating the fluorescence emission properties of [CPP-?2]2 in buffer solution which has a fluorescence lifetime of 12.0 ns, a peak anisotropy of 0.06 and a rotational correlation time of 5.2 ns (?ex=398 nm and ?em =620 nm). In contrast, free-CCP in buffer exhibits a fluorescence emission 5 times greater (at the same OD as [CPP-?2]2)with a lifetime of 15.5 ns (30% longer) and a peak anisotropy of 0.14 and a rotational correlation time of 0.083 ns. These results indicate that we are indeed measuring the emission of CPP bound to the peptide and we could estimate a molecular diameter of 36 E assuming a spherical shape.