Role of methanobactin in methane oxidation rates in the presence of mineral copper

矿物铜存在下甲烷杆菌素对甲烷氧化速率的作用

• 批准号: NE/F00608X/1
• 负责人: David Graham
• 金额: $ 73.82万
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF00608X%2F1
• 关键词: Role; methanobactin; methane; oxidation; rates

Methane-oxidizing bacteria (methanotrophs) are nature's primary mechanism for reducing levels of atmospheric methane, the second most important greenhouse gas. Understanding the abundance and distribution of these key organisms is critical to understanding nature's response to increased anthropogenic production of the gas and other releases, such as warming-mediated melting of permafrost zones. Unfortunately, despite the importance of these organisms, little is known about what controls in situ methanotroph ecology and activity. Factors such as soil moisture, pH, and oxygen, methane, and nitrogen levels have all been considered, and although each conditionally influences methanotroph diversity, none provides a consistent explanation for the abundance of these environmentally critical organisms, nor, the rate at which they destroy methane. Interestingly, copper (Cu), which is central to methanotroph metabolism, has not been studied in detail as a factor affecting in situ methanotroph activity, which is surprising since Cu is a component of particulate methane monooxygenase (pMMO), the most efficient enzyme at methane destruction in nature. Fortunately, recent discoveries have provided a possible explanation for why past work on methanotroph ecology has been less than conclusive, which is based on a new class of molecules called methanobactins (mb). mbs are small molecules produced by some methanotrophs that allow them to acquire, transport, and use Cu (i.e., chalkophores), especially from mineral and other more refractory Cu sources in the environment. Specifically, data show that mb conditionally sequesters Cu from iron-oxides and borosilicate glass, which promotes pMMO expression under conditions that would normally not support pMMO expression. Therefore, mb production clearly makes a significant difference in the amount of pMMO within a system and likely provides a competitive advantage to organisms that produce mb, especially within geochemical systems. Further, mb-mediation almost certainly impacts net methane oxidation activity because of the strength of pMMO as a methane-oxidizing agent. Although these observations are promising, little is known about the actual breadth of mb production among methanotrophs, which limits how far we can extend our predictions; i.e., only one mb has been crystallised (from Methylosinus trichosporium OB3b), although three other mbs have been partially characterized, which suggests that more mbs likely exist, but have not yet been found. Therefore, the purpose of this project is to determine the breadth of methanotrophs that produce mb-like compounds, and assess how mb and other factors impact pMMO expression, methanotroph ecology, and methane oxidation rates in geochemical settings. Initial experiments will be performed on twelve different methanotrophs to assess mb production in known strains and types, and in isolates from soils with different native Cu conditions. From this initial set of mbs, a sub-set will be chosen for further purification to compare Cu-binding properties and structures with the one known mb from M. trichosporium OB3b. Simultaneous to these studies, a comprehensive set of experiments assessing the impact of Cu mineralogy, nitrogen source, oxygen level, iron level, and other factors on pMMO expression and methane oxidation patterns will be performed using our model organism, M. trichosporium OB3b. Based on these data and also on the nature of new mbs discovered, final experiments on real soils will be carried out to calibrate Cu availability and MMO expression data from defined mineral sources and different soils collected from natural systems. The ultimate goal of the work is provide the most complete picture yet of what regulates MMO gene expression in geochemical settings. This will better inform future field studies on methanotrophs, assist in climate change studies, and provide a tool for predicting methane oxidation rates based on geochemical information.

甲烷氧化细菌（甲烷氧化菌）是自然界减少大气甲烷（第二大温室气体）水平的主要机制。了解这些关键生物的丰度和分布对于了解自然界对人为增加的气体生产和其他释放的反应至关重要，例如变暖介导的永久冻土区融化。不幸的是，尽管这些生物的重要性，很少有人知道是什么控制原位甲烷氧化菌的生态和活动。土壤湿度，pH值，氧气，甲烷和氮水平等因素都被考虑在内，虽然每个有条件地影响甲烷氧化菌的多样性，没有提供一个一致的解释，这些环境关键生物的丰度，也没有，他们破坏甲烷的速度。有趣的是，铜（Cu），这是中心的甲烷氧化菌代谢，还没有被详细研究作为影响原位甲烷氧化菌活性的因素，这是令人惊讶的，因为铜是颗粒甲烷单加氧酶（pMMO），在自然界中最有效的甲烷破坏酶的组分。幸运的是，最近的发现提供了一个可能的解释，解释了为什么过去在甲烷氧化菌生态学上的工作一直没有定论，这是基于一类新的分子，称为甲烷氧化菌素（mb）。MB是由一些甲烷氧化菌产生的小分子，其允许它们获取、运输和使用Cu（即，白垩基），特别是来自矿物和环境中其他更难处理的Cu源。具体地，数据显示，mb有条件地从铁氧化物和硼硅酸盐玻璃中螯合Cu，这在通常不支持pMMO表达的条件下促进pMMO表达。因此，甲基溴的生产显然使系统内的pMMO量有很大的不同，并可能为生产甲基溴的生物体提供竞争优势，特别是在地球化学系统内。此外，由于pMMO作为甲烷氧化剂的强度，mb-mediation几乎肯定会影响净甲烷氧化活性。虽然这些观察结果是有希望的，但对甲烷氧化菌中mb生产的实际广度知之甚少，这限制了我们可以将预测扩展到多远;即，只有一个MB结晶（来自发孢甲基弯菌OB 3b），尽管已经部分表征了其他三种mbs，这表明可能存在更多的mbs，但尚未发现。因此，本项目的目的是确定产生mb-like化合物的甲烷氧化菌的广度，并评估mb和其他因素如何影响pMMO表达，甲烷氧化菌生态，和甲烷氧化速率的关系。初步实验将进行12个不同的甲烷氧化菌，以评估MB的生产在已知的菌株和类型，并在不同的原生铜条件的土壤分离。从该初始的mbs组中，将选择一个子集用于进一步纯化，以将Cu结合性质和结构与来自M的一个已知的mb进行比较。发孢霉OB 3b.在这些研究的同时，将使用我们的模式生物M进行一系列综合实验，评估Cu矿物学、氮源、氧水平、铁水平和其他因素对pMMO表达和甲烷氧化模式的影响。发孢霉OB 3b.基于这些数据和新发现的mbs的性质，将在真实的土壤上进行最终实验，以校准来自定义的矿物来源和从自然系统收集的不同土壤的铜有效性和MMO表达数据。这项工作的最终目标是提供在地球化学环境中调节MMO基因表达的最完整的图片。这将更好地为未来的甲烷氧化菌实地研究提供信息，协助气候变化研究，并提供一种基于地球化学信息预测甲烷氧化速率的工具。

项目成果

Effects of copper mineralogy and methanobactin on cell growth and sMMO activity in <i>Methylosinus trichosporium</i> OB3b

铜矿物学和甲烷菌素对细胞生长和 sMMO 活性的影响

• DOI: 10.5194/bgd-8-2851-2011
• 发表时间: 2011
• 作者: Chi Fru E

Phenotypic Variability in Synthetic Biology Applications: Dealing with Noise in Microbial Gene Expression.

• DOI: 10.3389/fmicb.2016.00479
• 发表时间: 2016
• 期刊: Frontiers in microbiology
• 影响因子: 5.2
• 作者: Bandiera L;Furini S;Giordano E
• 通讯作者: Giordano E

Insight into Metal Removal from Peptides that Sequester Copper for Methane Oxidation.

• DOI: 10.1002/chem.201706035
• 发表时间: 2018-03-26
• 期刊: Chemistry (Weinheim an der Bergstrasse, Germany)
• 作者: Baslé A;El Ghazouani A;Lee J;Dennison C
• 通讯作者: Dennison C

Soil geochemistry confines microbial abundances across an arctic landscape; implications for net carbon exchange with the atmosphere

• DOI: 10.1007/s10533-014-9997-7
• 发表时间: 2014-08-01
• 期刊: BIOGEOCHEMISTRY
• 影响因子: 4
• 作者: Gray, N. D.;McCann, C. M.;Graham, D. W.
• 通讯作者: Graham, D. W.