Evidence for methanobactin “Theft” and novel chalkophore production in methanotrophs: impact on methanotrophic-mediated methylmercury degradation
Evidence for methanobactin “Theft” and novel chalkophore production in methanotrophs: impact on methanotrophic-mediated methylmercury degradation
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DOI：
10.1038/s41396-021-01062-1
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发表时间：
2021-07
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通讯作者：
C. Kang-Yun;Xujun Liang;P. Dershwitz;Wenyu Gu;A. Schepers;A. Flatley;J. Lichtmannegger;H. Zischka;Lijie Zhang;Xia Lu;B. Gu;Joshua C. Ledesma;Daly J. Pelger;A. DiSpirito;J. Semrau
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作者：
C. Kang-Yun;Xujun Liang;P. Dershwitz;Wenyu Gu;A. Schepers;A. Flatley;J. Lichtmannegger;H. Zischka;Lijie Zhang;Xia Lu;B. Gu;Joshua C. Ledesma;Daly J. Pelger;A. DiSpirito;J. Semrau
好氧甲烷营养受到铜的强烈控制，众所周知，甲烷营养菌利用不同的机制吸收铜。一些甲烷氧化菌分泌一种经过修饰的多肽--甲烷菌素--而另一些则利用表面结合蛋白(MOPE)及其分泌形式(MOPE*)来收集铜。由于不同的甲烷氧化菌具有不同的固定铜的方式，对铜的竞争对甲烷营养活性有显著影响。在此，我们证明了甲基微生物蛋白BG8、甲基微囊藻。罗克韦尔菌株和胶囊甲氧菌都缺乏合成甲烷结核蛋白的基因，不受多种形式的甲烷结核蛋白对铜的限制。有趣的是，嗯。白蛋白BG8和甲基胞囊藻属。罗克韦尔菌株被发现有类似的tombnT基因，编码摄取甲烷结核蛋白所需的TonB依赖的转运蛋白。数据表明，这些甲烷氧化菌“窃取”甲烷菌素，这种“窃取”增强了这些菌株降解甲基汞的能力，甲基汞是一种强有力的神经毒素。此外，当在Mm中删除mbnT时。在白蛋白BG8中，甲基汞在有甲烷结核存在的情况下的降解与没有添加MB时没有区别。胶囊Bath缺乏任何类似的TombnT，在存在或不存在甲烷结核蛋白的情况下都不能降解甲基汞。更确切地说，是Mc.CapacatusBath似乎依赖MOPE/MOPE*来收集铜。最后，不仅仅是Mm。蛋白BG8窃取甲烷菌素，它合成了一种新的胆红素，这表明一些甲烷氧化菌同时利用竞争和欺骗策略来收集铜。通过更好地了解这些策略，可以更有效地操纵甲烷营养群落，以减少甲烷排放，并增强汞的就地解毒作用。
Aerobic methanotrophy is strongly controlled by copper, and methanotrophs are known to use different mechanisms for copper uptake. Some methanotrophs secrete a modified polypeptide—methanobactin—while others utilize a surface-bound protein (MopE) and a secreted form of it (MopE*) for copper collection. As different methanotrophs have different means of sequestering copper, competition for copper significantly impacts methanotrophic activity. Herein, we show thatMethylomicrobium albumBG8,Methylocystissp. strain Rockwell, andMethylococcus capsulatusBath, all lacking genes for methanobactin biosynthesis, are not limited for copper by multiple forms of methanobactin. Interestingly,Mm. albumBG8 andMethylocystissp. strain Rockwell were found to have genes similar tombnTthat encodes for a TonB-dependent transporter required for methanobactin uptake. Data indicate that these methanotrophs “steal” methanobactin and such “theft” enhances the ability of these strains to degrade methylmercury, a potent neurotoxin. Further, whenmbnTwas deleted inMm. albumBG8, methylmercury degradation in the presence of methanobactin was indistinguishable from when MB was not added.Mc. capsulatusBath lacks anything similar tombnTand was unable to degrade methylmercury either in the presence or absence of methanobactin. Rather,Mc. capsulatusBath appears to rely on MopE/MopE* for copper collection. Finally, not only doesMm. albumBG8 steal methanobactin, it synthesizes a novel chalkophore, suggesting that some methanotrophs utilize both competition and cheating strategies for copper collection. Through a better understanding of these strategies, methanotrophic communities may be more effectively manipulated to reduce methane emissions and also enhance mercury detoxification in situ.