Bioluminescence: Molecular Mechanisms and Biochemical Control in Microorganisms

本研究的目的是了解细菌和鞭毛藻生物发光的分子和生化机制，包括所涉及的蛋白质编码基因及其进化起源。在鞭毛藻中，荧光素，一种可能来自叶绿素的四吡咯，被酶氧化产生光。这一反应的机制、酶促中间体和发射器的特性将利用重组技术从克隆基因和合成底物中产生的蛋白质进行研究。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研究。在细菌中，荧光素酶是一种黄蛋白单加氧酶，它催化脂肪醛氧化成相应的酸。荧光素酶结合的中间体以及附属的“发射器”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及其形成方式。荧光素酶可能的替代功能，例如保护细胞免受氧自由基的损伤，也将使用从人体伤口分离出来的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观，但它也是探索不寻常的生物能量过程的独特工具。本研究的目的是了解生物发光的分子和生化机制，并研究相关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；细菌和鞭毛藻。这种细菌发出蓝绿色的光。这些细胞通常与肠道内的高级生物体或专门的发光器官一起生活。鞭毛藻有一个非常不同的生物发光系统，似乎是独立进化而来的，它利用了一种与叶绿素有关的物质。鞭毛藻是海洋中赤潮的罪魁祸首，它们会产生强大的神经毒素，这些毒素会积聚在食用它们的贝类体内，从而使贝类对人类有毒。海洋在夜间发出的磷光也是由于鞭毛藻的生物发光。我们正在研究这种特殊的发光反应的生物化学原理。

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.