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.

一个非常重要的生物分子大家族称为脂质。它们包括脂肪和胆固醇等类固醇。另一个重要的亚家族是鞘脂 (SL) 和神经酰胺（类似于有两条尾巴的 SL）。所有这些脂质都存在于细胞膜中——科学家发现，动物、植物和细菌细胞都有一个保护性的、防水的外壳，该外壳由具有亲水（亲水）头部基团和长的水基的分子组成。讨厌（疏水）的尾巴。正是这些分子提供了该层。然而，它们不仅仅具有结构作用——它们已被证明在细胞分裂和细胞相互交流时发挥着重要作用。每个细胞中的脂质都有很高的周转率，它们不断地被制造和分解。这是严格控制的。特别是，SL 水平的变化与老年和阿尔茨海默病、帕金森病、糖尿病、哮喘、癌症和神经消耗性疾病等疾病密切相关。很难找到由植物、动物和细菌同时产生的分子。 SL 和神经酰胺正是如此 - 它们是由数百个分子组成的非常大的家族，每个分子都略有不同 - 它们含有氨基酸、脂肪酸和糖。然而，核心结构是相同的。对人类健康有直接影响的一个令人兴奋的研究领域是发现人类是许多不同类型细菌的宿主——这些细菌统称为微生物群/微生物组。这些细菌生活在我们的口腔、皮肤和肠道中，帮助我们代谢食物，也被认为发挥保护作用。他们让我们保持健康；所以我们必须了解什么时候细菌是好的，什么时候细菌是坏的——致病的？化学触发因素是什么？每个细胞都使用简单的构建模块通过多步骤途径制造 SL - 这些步骤由称为酶的分子机器催化（加速）。近年来，研究主要集中在人类 SL 生物合成所涉及的酶上，但对于微生物如何制造它们却知之甚少。当我们与美国科学家合作时，我们取得了突破，揭示了一种生活在淡水中的简单、安全的柄杆菌可以产生与我们相同的核心 SL，但它通过不同的途径产生它们 - 这就是所谓的趋同进化。然后我们利用遗传学来观察其他细菌的 DNA——我们认为少数微生物中存在的 DNA 分布更为广泛。我们甚至在大肠杆菌中发现了它们——一种非常常见的细菌，可能好也可能坏。科学家们已经使用大肠杆菌很多年了，因为它们安全、易于培养、易于设计，而且我们已经掌握了它们如何工作的蓝图。现在我们有了一个令人兴奋的发现，即大肠杆菌会产生 SL，我们希望了解该过程的分子细节 - 我们将研究所涉及的酶。我们将确定关键 SPT 酶的 3D 结构以及它如何与脂质载体结合。我们将探讨 SL 的两条脂质链是如何安装的。我们还将在特别标记的构建块中培养大肠杆菌，这将揭示核心分子是如何制造的。这是英国和美国科学家的团队努力，他们各自为这个项目带来了自己的专业知识。我们将利用化学家、微生物学家和分子生物学家的技能来揭开迄今为止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以及那些对分子如何进化感兴趣的人的兴趣。我们正在建立一个名为“脂质图”的清单，其中包含自然界中所有重要的脂质分子。由于大肠杆菌作为模式微生物已有超过 50 年的历史，因此很少能找到新的东西 - 因此在这一领域的工作令人兴奋。