Discovery of a cryptic sphingolipid pathway in E.coli - structural and functional analysis.

大肠杆菌中神秘鞘脂途径的发现 - 结构和功能分析。

• 批准号: BB/Y002210/1
• 负责人: Dominic Campopiano
• 金额: $ 72.11万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY002210%2F1
• 关键词: Discovery; cryptic; sphingolipid; pathway; E.coli

A very important, large family of biological molecules are called lipids. They include fats and steroids such as cholesterol. Another important sub-family are known as sphingolipids (SLs) and ceramides (which are like SLs with two tails). All these lipids are found in the cell membrane - scientists have found that animal, plants and bacterial cells have a protective, water-resistant outer shell that is composed of molecules with a water-loving (hydrophilic) head group and a long, water-hating (hydrophobic) tail. It is these molecules that provide that layer. However, they don't just have a structural role - they have been shown to be important when cells divide and when cells communicate with each other. There is a high turnover of lipids in the every cell, they are constantly being made and broken down. This is tightly controlled. In particular, changes in SL levels are strongly linked with old age and diseases such as Alzheimer's, Parkinson's Disease, diabetes, asthma, cancer and nerve-wasting diseases. It is rare to find molecules made by both plants, animals and bacteria; SLs and ceramides are exactly that - they are very large family of 100s of molecules, each slightly different - they contain amino acids, fatty acids and sugars. However, the core structures are the same. An exciting area of research with direct implications for human health is the discovery that humans are hosts for many different types of bacteria - collectively these are known as the microbiota/microbiome. These bacteria live in our mouths, on our skin and in our gut and help us metabolise our food and are also thought to play protective roles. They keep us healthy; so we have to understand when is a bacteria good and when is a bacteria bad - pathogenic? What are the chemical triggers?Every cell make SLs by a multi-step pathway using simple building blocks - the steps are catalysed (sped up) by molecular machines called enzymes. In recent years, research has focussed on the enzymes involved in human SL biosynthesis but very little is known about how microbes make them. We made a breakthrough when we teamed up with American scientists to reveal that a simple, safe Caulobacter bacterium that lives in fresh water can make the same core SLs as we can, but it makes them through a different route - that's called convergent evolution. We then used genetics to look at the DNA of other bacteria - what we thought to present in a small number of microbes is more much more widespread. We have even found them in E. coli - a very common bacteria that can be good and bad. Scientists have used E. coli for many years because they are safe and easy to grow, easy to engineer and we have a blue-print of how they work. Now we have made an exciting discovery that E. coli make SLs we want to understand the molecular details of the process - we will study the enzymes involved. We will determine the 3D structure of the key SPT enzyme and how it engages with a lipid carrier. We will explore how the two lipids chains of SLs are installed. We will also grow E.coli in specially marked building blocks and that will reveal how the core molecules are made. This is a team effort with UK and USA scientists each bringing their own expertise to this project. We will use our skills as chemists, microbiologists and molecular biologists to uncover the secrets that have been hidden in E. coli until now. Our results will be of interest to academic microbiologists and chemists as well as those interested how molecules evolved. We are building a inventory called Lipid Maps of all the important lipid molecules in Nature. Because E. coli has been a model microbe for >50 years, it is rare to find something new - so it is exciting to work in this area.

一个非常重要的大型生物分子家族称为脂质。它们包括脂肪和类固醇，例如胆固醇。另一个重要的亚家族被称为鞘脂（SLS）和神经酰胺（类似于带有两个尾巴的SL）。所有这些脂质都在细胞膜中发现 - 科学家发现动物，植物和细菌细胞具有保护性的，耐水的外壳，由带有热爱水的（亲水性）头的分子组成，并且是长长的水，蜂蜜（疏水）尾巴。这些分子提供了该层。但是，它们不仅具有结构性的作用 - 当细胞分裂和细胞相互通信时，它们已被证明很重要。每个单元格中脂质的周转率很高，它们不断地制造和分解。这是严格控制的。特别是，SL水平的变化与老年和疾病（例如阿尔茨海默氏病，帕金森氏病，糖尿病，哮喘，癌症和浪费神经疾病）密切相关。很少能找到由植物，动物和细菌制成的分子。 SLS和神经酰胺正是如此 - 它们是一个非常大的100个分子家族，每个家族都略有不同 - 它们含有氨基酸，脂肪酸和糖。但是，核心结构是相同的。令人兴奋的研究领域对人类健康的直接影响是发现人类是许多不同类型细菌的宿主 - 总的来说，这些被称为微生物群/微生物组。这些细菌生活在我们的口中，皮肤和肠道中，并帮助我们代谢食物，也被认为扮演着保护角色。他们使我们保持健康；因此，我们必须了解细菌何时好，何时细菌不良 - 致病性？什么是化学触发器？每个细胞使用简单的构建块通过多步途径制造SLS - 台阶是由称为酶的分子机催化（加速）。近年来，研究集中在与人类SL生物合成有关的酶上，但对微生物的制造方式知之甚少。当我们与美国科学家合作以揭示生活在淡水中的一种简单，安全的花椰菜细菌可以使它们与我们的核心SLS相同时，我们取得了突破，但它使它们穿过另一条路线 - 这称为融合进化。然后，我们使用遗传学来研究其他细菌的DNA-我们认为在少数微生物中呈现的内容更为广泛。我们甚至已经在大肠杆菌中找到了它们 - 一种非常常见的细菌，可能是好是坏的。科学家已经使用了大肠杆菌多年了，因为它们安全易于生长，易于设计，并且我们的工作方式有蓝色印刷。现在，我们已经提出了一个令人兴奋的发现，即大肠杆菌使我们想了解该过程的分子细节 - 我们将研究所涉及的酶。我们将确定密钥SPT酶的3D结构以及它如何与脂质载体互动。我们将探讨如何安装SLS的两个脂质链。我们还将在特殊标记的构件中生长大肠杆菌，这将揭示如何制作核心分子。这是英国和美国科学家的团队努力，各自将自己的专业知识带入了这个项目。我们将以化学家，微生物学家和分子生物学家的技能来揭示直到现在隐藏在大肠杆菌中的秘密。我们的结果将引起学术微生物学家和化学家的感兴趣，以及分子如何发展的人们感兴趣。我们正在建立一个自然界所有重要脂质分子的脂质图的库存。由于大肠杆菌已经成为模型型薄荷含量超过50年，因此很少能找到新的东西 - 因此在这一领域工作是令人兴奋的。