Structure Function Studies on Phytochrome

适应外部光环境变化的能力对植物的生存尤其重要，因为与动物不同，植物依靠阳光进行光合作用，它们没有神经肌肉系统，使它们能够移动到更理想的光环境中。因此，植物拥有独特的光敏感光分子光敏色素，使它们能够感知环境中光的强度、方向和光谱质量的频繁波动。本提案中的实验概述旨在提供关于光敏色素结构的新信息，并解决光敏色素是光调节酶的假设。这些研究的长期目标是确定光敏色素功能的结构基础。对于我们的一些研究，我们将；采用单细胞绿藻Mesotaenium caldariorum作为模型系统。鉴定这种藻类光敏色素信号转导途径的成分将为分析相当复杂的高等植物组织中的光敏色素反应途径提供有用的工具。适应外部光环境变化的能力对植物的生存尤其重要，因为与动物不同，植物依靠阳光进行光合作用，它们没有神经肌肉系统，这使它们能够转移到更理想的光环境中。这个项目的重点是光敏色素，一种存在于所有植物中的光感蛋白，它能感知照射在植物上的光的方向、强度和颜色。具体来说，我们感兴趣的是光敏色素是如何接收这些信息的，它是如何传递给其他分子的，以及最终这些过程是如何导致植物生长和发育的变化的（例如种子发芽，开花和生长速度）。由于地球上所有的生命都依赖于绿色植物的光合作用，因此对植物适应光环境的生化过程的基本了解是非常重要的。

The ability to adjust to changes in the external light environment is especially important to plant survival because, unlike animals, plants depend on sunlight for photosynthesis and they do not have a neuromuscular system which allows them to move to a more optimum light environment. Plants therefore possess the unique light-sensing photoreceptor molecule phytochrome which enables them to perceive the frequent fluctuations of intensity, direction and spectral quality of light in their environment. Experiments outlines in this proposal seek to provide new information on phytochrome structure and to address the hypothesis that phytochrome is a light-regulated enzyme. The long tern goal of these studies is to define the structural basis for phytochrome function. For a number of our studies, we will; employ the unicellular green alga Mesotaenium caldariorum as a model system. Identification of the components of the phytochrome signal transduction pathway in this algal should produce useful tools for analysis of phytochrome response pathways in considerably more complex higher plant tissues. %%% The ability to adjust to changes in the external light environment is especially important to plant survival because, unlike animals, plants depend on sunlight for photosynthesis and they do not have a neuromuscular system which allows them to move to a more optimum light environment. This project focuses on phytochrome, a light-sensing protein found in all plants which perceives the direction, intensity and color of light that impinges on the plant. Specifically, we are interested in how this information is received by phytochrome, how it passed on to other molecules, and ultimately how these processes lead to changes in plant growth and development (e.g. seed germination, flowering and growth rate). Since all life on earth depends on photosynthesis by green plants, a basic understanding of the biochemical processes which enable plants to adapt to their light environment is of great importance.