Function and Assembly of CO2 Assimilatory Enzymes

描述(由申请人提供)：健康的细胞活动依赖于中间代谢关键酶的适当折叠、组装和随后的催化功能。我们的主要兴趣和长期目标是了解控制二氧化碳被同化为细胞有机化合物的过程的因素，这是所有生物体共同的过程。初级二氧化碳同化是由核酮糖1，5-二磷酸(RuBP)羧化酶/加氧酶(Rubisco)催化的。该蛋白还具有作为内部单加氧酶的功能，并在适当的条件下催化RuBP的氧解裂解。因此，Rubisco是一种双功能蛋白质，其中相同的多肽链催化细胞代谢的两个相互竞争的反应的第一步；事实上，最近的研究表明，这种独特的酶可能作为异构酶、异构体酶和磷酸酶发挥功能，从而产生独特的催化产物。因此，这项研究针对两个主要目标：(1)通过结合随机突变和遗传选择程序以及功能酶学方法来解决许多长期存在的Rubisco功能问题；(2)使用独特的和新发现的微生物Rubisco分子来促进对酶功能的了解。这些目标为长期存在争议的结构、功能、折叠和组装等关键问题提供了新的和新的方法。事实上，Rubisco是一个主要的例子，在这种蛋白质中，X射线结构研究没有提供关于酶效率或底物选择性基础的答案。因此，最重要的是将新的方法纳入对这种蛋白质的研究中，以便我们可以了解这种单一蛋白质(Rubisco)如何通过偏爱一种催化功能来控制代谢过程。因此，这项研究的微生物学/遗传学/生化结合的重点将极大地增强现有的X射线结构模型，并将提供许多关于这种重要蛋白质的功能和控制新陈代谢许多方面的独特能力的新见解。特别令人感兴趣的是蛋白质折叠和催化与细胞功能的关系。

DESCRIPTION (provided by applicant): Healthy cellular activity is dependent on the proper folding, assembly, and subsequent catalytic function of key enzymes of intermediary metabolism. Our primary interest and long term goal is to understand factors which regulate the process by which carbon dioxide is assimilated into organic compounds of the cell, a process which is common to all organisms. Primary carbon dioxide assimilation is catalyzed by the enzyme ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO). This protein also has the capacity to function as an internal monooxygenase and catalyzes the oxygenolytic cleavage of RuBP under suitable conditions. RubisCO is thus a bifunctional protein in which the same polypeptide chain catalyzes the first step of two competing reactions of cellular metabolism; indeed recent studies indicate that this unique enzyme may function as an isomerase, an epimerase, and a phosphatase as well, with the consequent production of unique products of catalysis. This study is thus directed at two major objectives: (1) the solving of many long standing issues of RubisCO function through the incorporation of procedures of random mutagenesis and genetic selection, coupled to functional enzymological approaches; (2) the use of unique and newly discovered microbial RubisCO molecules to facilitate an understanding of enzyme function. These objectives present novel and fresh approaches to key questions of structure, function, folding and assembly that have long been at issue. Indeed, RubisCO is a major example of a protein where X-ray structural studies have not provided answers as to the basis of enzyme efficiency or substrate selectivity. Thus, it is paramount that the new approaches become incorporated into investigations of this protein so that we may gain an understanding as to how this single protein (RubisCO) controls the course of metabolism by favoring one catalytic function over another. The combined microbiological/genetic/biochemical focus of this study will thus greatly enhance available X-ray structural models and will provide many new insights relative to this important protein's function and unique ability to control many aspects of metabolism. Of particular interest will be the relationship of protein folding and catalysis to cellular function.