甲烷氧化菌素

甲烷氧化菌素（Methanobactin, 缩写为Mbn）是一类由核糖体合成的翻译后修饰肽，其特征是特定的半胱氨酸残基被修饰成恶唑酮-硫代酰胺基团^[2]。分子式为C₄₅N₁₂O₁₄H₆₂Cu，分子量为1216 Da^[3]。根据系统发育分析被分为五大类(groups Ⅰ–Ⅴ)^[2] 。Mbn对铜离子具有高度亲和性，在甲烷氧化菌的铜稳态生理调控中具有重要的作用^[2]。最早发现于甲烷氧化菌Methylosinus trichosporium OB3b中，也发现存在于多种非甲烷氧化细菌中^[4]^[5]。

甲烷氧化菌素具有铜螯合特性、氧化酶活性^[6]、解汞毒能力以及抑菌作用等^[2]。被认为在治疗铜代谢相关疾病、细菌感染性疾病等方面具有潜在开发价值^[2]。研究证实Mbn能够高效收集铜以支持甲烷氧化反应，并且直接调控甲烷氧化的铜开关^[7]。

生物合成机制

甲烷氧化菌素的生物合成机制尚未完全明确。Mbn的生物合成涉及多个基因和酶的参与，主要包括MbnA、MbnB、MbnC等基因和相应的酶。^[2]

Mbn的生物合成过程包括以下几个关键步骤^[2]：

MbnA基因编码的酶催化Mbn的前体肽的合成
MbnB基因编码的酶参与Mbn的后翻译修饰，包括恶唑酮-硫代酰胺基团的形成
MbnC基因编码的酶参与Mbn的后续修饰和成熟过程。

在这些生物合成步骤中，MbnAoxa和MbnBC的催化作用是形成具有生物活性的酶促产物的关键步骤。但是Mbn前体肽的切除机制以及不同菌株中Mbn生物合成的差异性等仍待了解^[2]。

参考文献

[1]
El Ghazouani, A; Baslé, A; Firbank, SJ; Knapp, CW; Gray, J; Graham, DW; Dennison, C. Copper-binding properties and structures of methanobactins from Methylosinus trichosporium OB3b.. Inorganic chemistry. 2011-02-21, 50 (4): 1378–91. PMID 21254756. doi:10.1021/ic101965j.
[2]
Long, Zhaolin; Li, Shoujie; Kang, Bo; Cheng, Wei. Advances in methanobactin. Chinese Science Bulletin. 2023-04-01. doi:10.1360/TB-2023-0006.
[3]
Kim, HJ; Graham, DW; DiSpirito, AA; Alterman, MA; Galeva, N; Larive, CK; Asunskis, D; Sherwood, PM. Methanobactin, a copper-acquisition compound from methane-oxidizing bacteria.. Science (New York, N.Y.). 2004-09-10, 305 (5690): 1612–5. PMID 15361623. doi:10.1126/science.1098322.
[4]
Kenney, GE; Rosenzweig, AC. Genome mining for methanobactins.. BMC biology. 2013-02-26, 11: 17. PMID 23442874. doi:10.1186/1741-7007-11-17.
[5]
Dassama, LM; Kenney, GE; Rosenzweig, AC. Methanobactins: from genome to function.. Metallomics : integrated biometal science. 2017-01-25, 9 (1): 7–20. PMID 27905614. doi:10.1039/c6mt00208k.
[6]
Choi, DW; Semrau, JD; Antholine, WE; Hartsel, SC; Anderson, RC; Carey, JN; Dreis, AM; Kenseth, EM; Renstrom, JM; Scardino, LL; Van Gorden, GS; Volkert, AA; Wingad, AD; Yanzer, PJ; McEllistrem, MT; de la Mora, AM; DiSpirito, AA. Oxidase, superoxide dismutase, and hydrogen peroxide reductase activities of methanobactin from types I and II methanotrophs.. Journal of inorganic biochemistry. 2008-08, 102 (8): 1571–80. PMID 18372044. doi:10.1016/j.jinorgbio.2008.02.003.
[7]
Semrau, JD; Jagadevan, S; DiSpirito, AA; Khalifa, A; Scanlan, J; Bergman, BH; Freemeier, BC; Baral, BS; Bandow, NL; Vorobev, A; Haft, DH; Vuilleumier, S; Murrell, JC. Methanobactin and MmoD work in concert to act as the 'copper-switch' in methanotrophs.. Environmental microbiology. 2013-11, 15 (11): 3077–86. PMID 23682956. doi:10.1111/1462-2920.12150.

[1] [1]
El Ghazouani, A; Baslé, A; Firbank, SJ; Knapp, CW; Gray, J; Graham, DW; Dennison, C. Copper-binding properties and structures of methanobactins from Methylosinus trichosporium OB3b.. Inorganic chemistry. 2011-02-21, 50 (4): 1378–91. PMID 21254756. doi:10.1021/ic101965j.

[TB-2023-0006-2] [2]
Long, Zhaolin; Li, Shoujie; Kang, Bo; Cheng, Wei. Advances in methanobactin. Chinese Science Bulletin. 2023-04-01. doi:10.1360/TB-2023-0006.

[3] [3]
Kim, HJ; Graham, DW; DiSpirito, AA; Alterman, MA; Galeva, N; Larive, CK; Asunskis, D; Sherwood, PM. Methanobactin, a copper-acquisition compound from methane-oxidizing bacteria.. Science (New York, N.Y.). 2004-09-10, 305 (5690): 1612–5. PMID 15361623. doi:10.1126/science.1098322.

[4] [4]
Kenney, GE; Rosenzweig, AC. Genome mining for methanobactins.. BMC biology. 2013-02-26, 11: 17. PMID 23442874. doi:10.1186/1741-7007-11-17.

[5] [5]
Dassama, LM; Kenney, GE; Rosenzweig, AC. Methanobactins: from genome to function.. Metallomics : integrated biometal science. 2017-01-25, 9 (1): 7–20. PMID 27905614. doi:10.1039/c6mt00208k.

[6] [6]
Choi, DW; Semrau, JD; Antholine, WE; Hartsel, SC; Anderson, RC; Carey, JN; Dreis, AM; Kenseth, EM; Renstrom, JM; Scardino, LL; Van Gorden, GS; Volkert, AA; Wingad, AD; Yanzer, PJ; McEllistrem, MT; de la Mora, AM; DiSpirito, AA. Oxidase, superoxide dismutase, and hydrogen peroxide reductase activities of methanobactin from types I and II methanotrophs.. Journal of inorganic biochemistry. 2008-08, 102 (8): 1571–80. PMID 18372044. doi:10.1016/j.jinorgbio.2008.02.003.

[7] [7]
Semrau, JD; Jagadevan, S; DiSpirito, AA; Khalifa, A; Scanlan, J; Bergman, BH; Freemeier, BC; Baral, BS; Bandow, NL; Vorobev, A; Haft, DH; Vuilleumier, S; Murrell, JC. Methanobactin and MmoD work in concert to act as the 'copper-switch' in methanotrophs.. Environmental microbiology. 2013-11, 15 (11): 3077–86. PMID 23682956. doi:10.1111/1462-2920.12150.

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