Pathways and Enzymes from Fungal Genomes for Degradation of Aromatic Compounds

真菌基因组降解芳香族化合物的途径和酶

• 批准号: RGPIN-2014-06274
• 负责人: Powlowski, Justin
• 金额: $ 2.55万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588914
• 关键词: Pathways; Enzymes; Fungal; Genomes; Degradation

In recent years there has been considerable interest in many countries, especially the US, in sequencing the genomes of fungi. Sequencing a genome nowadays is relatively easy and inexpensive, and there are over 150 fungal genome sequences available in public databases, with the number growing fast. Fungi are the master degraders and recyclers of the biosphere, and have the ability to transform almost any material, first into its constituent parts and then carbon dioxide and water. They do so in order to obtain carbon and energy to grow, using protein catalysts called enzymes to drive each step in the degradation process. Much of the interest in sequencing fungal genomes lies in the possibility of identifying genes encoding the complete repertoire of enzymes that each fungus has to contribute to these degradation activities. Once identified, it is believed that the degradative power of these enzymes can be harnessed to degrade complex plant materials to useful products, such as ethanol and fine chemicals, or to destroy pollutants. Indeed, many commercial processes, from baking to biofuel production already rely on fungal enzymes. However these come from a handful of fungi, and with well over a million fungal species in the world living in a wide variety of habitats, there is a huge reservoir of potentially useful enzymes that remains untapped. One group of chemicals that fungi can degrade are the aromatic compounds, which are defined by the presence of one or more benzene rings, but otherwise are very diverse in terms of what is attached to those rings. A large variety of aromatic compounds is made by plants, and we are exposed to those in our diets, but we also use large quantities of aromatics for manufacturing and in industrial processes. Although human metabolism of such compounds is generally directed towards detoxification and elimination, fungi and bacteria utilize them as sole sources of carbon and energy to grow. While many genes in fungal genomes have been assigned functions in the degradation of aromatic compounds, there is often very little experimental evidence that supports these assignments. The aim of this proposal is to connect fungal genome sequence data to experimental evidence for the functions of genes and their encoded enzymes in metabolic pathways used for the degradation of aromatic compounds. Initially, we are focusing on a few species, with known abilities to degrade a range of these compounds, to produce well-defined and complete sets of data for the genes and corresponding enzymes involved in the degradation pathways. From these well-defined examples we will expand to other species across the fungal tree of life, and to a broader range of compounds. This work is expected to be significant in a number of ways. First, it will allow a large group of genes in fungal genomes, which currently are poorly or incorrectly understood, to be solidly linked to functional properties. Many experimental studies that use the genome information can only be interpreted properly with the information that we will be generating. Second, it will reveal strategies, currently not well understood, used by fungi for the degradation of a large group of compounds of environmental significance and potentially related to human health. This will allow better prediction of the fate of aromatic compounds in the environment and the metabolic capabilities of fungi. Third, it is anticipated that some of the enzymes identified will have novel catalytic properties that will contribute to new biochemical knowledge and be useful for specific applications as catalysts, for example in the degradation of chemical wastes or conversion or plant waste to biodiesel.

近年来，许多国家，特别是美国，对真菌基因组测序产生了相当大的兴趣。 如今，对基因组进行测序相对容易且便宜，公共数据库中有超过150种真菌基因组序列，而且数量还在快速增长。 真菌是生物圈的主要降解者和回收者，并且有能力将几乎任何材料转化为其组成部分，然后是二氧化碳和水。 它们这样做是为了获得碳和能量来生长，使用称为酶的蛋白质催化剂来驱动降解过程中的每一步。 对真菌基因组测序的兴趣在于鉴定编码每种真菌都有助于这些降解活动的酶的完整库的基因的可能性。一旦确定，人们认为这些酶的降解能力可以用来将复杂的植物材料降解为有用的产品，如乙醇和精细化学品，或破坏污染物。 事实上，从烘焙到生物燃料生产的许多商业过程已经依赖于真菌酶。 然而，这些来自少数真菌，并且世界上有超过一百万种真菌物种生活在各种各样的栖息地，有一个巨大的潜在有用的酶库尚未开发。 真菌可以降解的一组化学物质是芳香族化合物，它们由一个或多个苯环的存在来定义，但就连接到这些环的物质而言，它们是非常多样的。 大量的芳香化合物是由植物制造的，我们在饮食中接触到这些化合物，但我们也在制造和工业过程中使用大量的芳香化合物。 虽然人类对这些化合物的代谢通常是针对解毒和消除，但真菌和细菌利用它们作为唯一的碳源和能量来生长。 虽然真菌基因组中的许多基因已被分配在芳香族化合物的降解中的功能，但通常很少有实验证据支持这些分配。 该提案的目的是将真菌基因组序列数据与用于降解芳香族化合物的代谢途径中的基因及其编码酶的功能的实验证据联系起来。 最初，我们专注于几个物种，具有已知的能力，降解这些化合物的范围，产生明确的和完整的数据集的基因和相应的酶参与降解途径。从这些定义明确的例子中，我们将扩展到真菌生命树中的其他物种，以及更广泛的化合物。 预计这项工作将在若干方面具有重要意义。首先，它将允许真菌基因组中的一大组基因与功能特性紧密联系，这些基因目前还不清楚或不正确。许多使用基因组信息的实验研究只能用我们将要产生的信息来正确解释。第二，它将揭示目前还不清楚的真菌用于降解大量具有环境意义并可能与人类健康有关的化合物的策略。这将允许更好地预测环境中芳香族化合物的命运和真菌的代谢能力。 第三，预计一些确定的酶将具有新的催化特性，这将有助于新的生物化学知识，并可用于作为催化剂的特定应用，例如在化学废物的降解或植物废物转化为生物柴油。