Biochemistry of Luminescence

9630861下村技术摘要生物发光存在于各种各样的生物体中，涉及不同类型的化合物和光发射的化学过程中的反应机理。这项研究集中在对真菌生物发光的生物化学理解上，在过去的40年里，几个小组一直在挑战这一问题，但都没有成功。真菌的生物发光是独一无二的，与目前已知的所有其他生物发光系统明显不同。它们的发光是连续的，几乎持续数天，发光反应是由表面活性剂催化的，而不是传统的荧光素酶。在生物发光的化学研究中，关键成分的鉴定和表征是最重要的。因此，本项目的中心主题是各种真菌荧光素及其前体的结构测定。发光蘑菇Panellus stipticus的荧光素被发现具有复杂的结构，由三个前体分子(酮醛PS-A和PS-B)和两个甲胺分子组成；该分子含有一个不寻常的9元环。为了确定P.stipticus荧光素的完整结构，将制备一个在分子的关键位置含有C-13原子的荧光素样本，并将利用岸信介在哈佛大学实验室新开发的核磁共振技术对该样本进行分析。近年来，从发光真菌Mycena Citricolor中分离到10多种纯态荧光素前体，其结构正在研究中。当这些前体与十烷胺反应时，很容易形成荧光素；由此获得的柑橘红色荧光素的结构将被确定。显然，所有发光真菌的荧光素都来自一种醛类前体，如PS-A和PS-B，以及伯胺，并且它们都含有相同的发光发色团。这样的发色团将从两种以上不同类型的真菌荧光素的结构中鉴定出来。在真菌的发光反应中，在超氧阴离子和阳离子表面活性剂的存在下，荧光素被分子氧氧化，发射的光子在其中没有明显作用，但该反应可以消除组织中有害的超氧阴离子；拟议的研究可能揭示该反应的其他重要作用。模拟荧光素酶的表面活性物质的参与表明，这项研究可能有助于理解酶的作用。真菌荧光素对超氧阴离子的高度敏感性表明它可能被用作超氧阴离子探针。在生物发光的化学研究中，最重要的是鉴定和表征参与发光反应的关键物质。荧光素是一种存在于发光生物体中的物质，当它被氧化时会发光。本研究的中心主题是找出各种真菌荧光素及其前体的结构。一种夜光蘑菇的荧光素，命名为Panellus stipticus，是一种复杂的化合物，含有不寻常的9个碳原子环。PI计划通过制备一个在分子的关键位置包含比平均碳原子(13C)更重的荧光素样本来确定该荧光素的完整结构，然后通过一种称为核磁共振(核磁共振)光谱的过程对该样本进行分析。哥斯达黎加发光烟草真菌(Mycena Citricolor)含有10多种荧光素前体，这些前体是最近分离纯化的；我们正在努力确定它们的化学结构。这些前体分子在用一种名为癸胺的物质处理时很容易转化为荧光素；我们计划研究这些荧光素的化学结构。现在似乎很明显，所有发光真菌的荧光素都来自相似的材料，而且它们都包含一种相同的发光结构，称为发色团。我们计划根据发光真菌中两种以上不同类型真菌荧光素的化学结构来鉴定这样的发色团，在某些负离子(称为超氧阴离子)和洗涤剂的存在下，荧光素被分子氧氧化时发出光；在这个反应中，发出的光子没有明显的作用，但反应可以从组织中消除有害的超氧阴离子。模拟酶的洗涤剂的参与表明，这里描述的研究也可能有助于理解酶的作用。真菌荧光素对超氧阴离子的高度敏感性也暗示了将这种材料用作检测生物系统中有害超氧阴离子存在的一种手段的可能性。

9630861 Shimomura Technical abstract Bioluminescence occurs in a wide variety of organisms, involving diverse types of compounds and reaction mechanisms in the chemical process of light emission. This research is focused on the biochemical understanding of the bioluminescence of fungi, which has been challenged by several groups in the past 40 years without success. The bioluminescence of fungi is unique and distinctly differs from all other bioluminescent systems presently known. Their glow is continuous and nearly constant for days, and the light-emitting reaction is catalyzed by surfactants, not by conventional luciferases. In the chemical study of bioluminescence, the identification and characterization of the key components involved are most important. Thus, the central theme of this project is the structure determination of various fungal luciferins and their precursors. The luciferin of the luminous mushroom Panellus stipticus was found to have a complicated structure consisting of three molecules of the precursor (ketoaldehydes PS- A and PS-B) and two molecules of methylamine; the molecule contains an unusual 9-membered ring. In order to determine the complete structure of the P. stipticus luciferin, a luciferin sample that contains C-13 atoms at the key positions of the molecule will be prepared, and the sample will be analyzed by a NMR technique newly developed at Dr. Kishi's lab at Harvard. From the luminous fungus Mycena citricolor, more than 10 kinds of luciferin precursor were recently isolated in pure states; their structures are now being elucidated. These precursors readily form luciferins when reacted with decylamine; the structures of the M. citricolor luciferins thus obtained will be determined. It seems apparent that the luciferin of all luminous fungi are derived from a precursor of aldehydic type, such as PS-A and PS-B, and a primary amine, and that all of them contain an identical light-emitting chromophore. Such a chromophore will be identified from t he structures of more than two different types of fungal luciferins. In the luminescence reaction of fungi, a luciferin is oxidized by molecular oxygen in the presence of superoxide anions and a cationic surfactant, in which the emitted photons play no apparent role, but by which the reaction can eliminate harmful superoxide anions in the tissue; the proposed study might uncover other important roles for the reaction. The involvement of a surfactant that mimics a luciferase suggests that the study may contribute to the understanding of enzymatic action. The high sensitivity of fungal luciferin to superoxide anions suggests its possible use as a superoxide probe. Non-technical abstract In the chemical study of bioluminescence, it is most important to identify and characterize the key substances involved in the light emitting reaction. Luciferin is a type of substance that exits in luminous organisms and emits light when it is oxidized. The central theme of this research is to find out the structures of various fungal luciferins and their precursors. The luciferin of one type of luminous mushroom, named Panellus stipticus, was found to be a complicated compound that includes and unusual ring of 9 carbon atoms. The PI plans to determine the complete structure of this luciferin by preparing a luciferin sample that contains a heavier-than-average carbon atom (13C) at the key positions of the molecule, and then analyzing this sample by a process known as nuclear magnetic resonance (NMR) spectroscopy. The luminous Costa Rican tobacco fungus (Mycena citricolor) contains more that 10 kinds of luciferin precursor which have been recently isolated and purified; we are now trying to determine their chemical structures. These precursor molecules are readily converted to luciferins when treated with a substance called decylamine; we plan to investigate the chemical structures of these luciferins. Now it seems apparent that the luciferins of all luminous fungi are derived from similar mat erials, and that all of them contain an identical light-emitting structure called a chromophore. We plan to identify such a chromophore based on the chemical structures of more than two different types of fungal luciferins In luminous fungi, light is emitted when a luciferin is oxidized by molecular oxygen, in the presence of certain negative ions (called superoxide anions) and a detergent; in this reaction, the emitted photons play no apparent role, but the reaction can eliminate the superoxide anions, which are harmful, from the tissue. The involvement of the detergent that mimics an enzyme suggests that the study described here may also contribute to the understanding of enzymatic action. The high sensitivity of fungal luciferin to superoxide anions also suggests the possibility of using this material as a means of detecting the presence of harmful superoxide anions in biological systems.