Bioluminescence: Molecular Mechanisms and Biochemical Control in Microorganisms

本研究的目的是了解细菌和甲藻中生物发光的分子和生化机制，包括编码相关蛋白质的基因及其进化起源。在甲藻中，荧光素，一种可能来自叶绿素的四吡咯，被酶氧化产生光。将利用克隆基因和合成底物(S)重组技术产生的蛋白质来研究这一反应的机理、酶促中间体和发射体的身份。这些基因的结构、序列和组织将被确定，它们的进化起源将被调查。在细菌中，荧光素酶是一种黄素蛋白单加氧酶，催化脂肪醛氧化成相应的酸。荧光素酶结合的中间体以及辅助的“发射体”蛋白将使用光物理和酶学技术来表征，以研究初级激发态的性质和它是如何形成的。荧光素酶可能的替代功能，如保护细胞免受氧自由基的破坏，也将使用从人体伤口分离出来的在100%氧气中生长的细菌进行研究。虽然生物体发出的可见光是自然界罕见的奇特现象，但它也是探索不寻常的生物能量过程的独特工具。这项研究的目的是了解生物发光的分子和生化机制，并检查涉及的基因的控制和进化起源。在这项研究中，我们将主要使用简单的海洋单细胞生物：细菌和甲藻。这种细菌发出蓝绿色的光。这些细胞通常与肠道或特殊发光器官中的高等生物生活在一起。甲藻有一个非常不同的生物发光系统，似乎是独立进化的，并利用了一种与叶绿素有关的物质。甲藻是海洋水华(称为赤潮)的罪魁祸首，它们在海洋中产生强烈的神经毒素，积累在摄取它们的贝类中，从而使贝类对人类有毒。夜间海洋的磷光也是由于甲藻的生物发光。我们的研究是为了了解这种特殊发光反应的生物化学。

The objective of this research is to understand the molecular and biochemical mechanisms of bioluminescence in bacteria and dinoflagellates, including the genes coding for the proteins involved and their evolutionary origins. In dinoflagellates, the luciferin, a tetrapyrrole probably derived from chlorophyll, is oxidized enzymatically to produce light. The mechanism of this reaction, the enzymatic intermediates, and the identity of the emitter, will be studied using proteins produced by recombinant techniques from cloned genes and synthetic substrate(s). The structures, sequences and organization of these genes will be determined, and their evolutionary origins will be investigated. In bacteria, luciferase is a flavoprotein monooxygenase which catalyzes the oxidation of aliphatic aldehydes to the corresponding acids. Luciferase-bound intermediates along with accessory "emitter" proteins will be characterized using photophysical and enzymological techniques to investigate the nature of the primary excited state and how it is formed. Possible alternative functions of luciferase, such as protection against cellular damage by oxygen radicals, will also be studied using bacteria which grow in 100% oxygen and were isolated from a human wound. %%% Although the emission of visible light by living organisms is a rare, curiosity of nature, it is also a unique tool for exploring unusual biological energetic processes. The objective of the research is to understand the molecular and biochemical mechanisms of bioluminescence, and to examine the control and evolutionary origin of the genes involved. We will principally use simple marine unicellular organisms in this study; bacteria and dinoflagellates. The bacteria emit blue-green light. These cells often live in association with higher organisms in the gut tract or in specialized light emitting organs. Dinoflagellates have a very different bioluminescence system which seems to have evolved independently, and makes use of a substance related to chlorophyll. The dinoflagellates are responsible for the blooms (called red tides) in the ocean, where they produce potent neurotoxins which accumulate in the shellfish that ingest them, thus making the shellfish poisonous for man. The phosphorescence of the ocean seen at night is also due to dinoflagellate bioluminescence. Our studies are learn about the biochemistry for this peculiar light emission reaction.