NMR, mass spectrometry and chemical evidence reveal a different chemical structure for methanobactin that contains oxazolone rings.
NMR, mass spectrometry and chemical evidence reveal a different chemical structure for methanobactin that contains oxazolone rings.
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DOI：
10.1021/ja804747d
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发表时间：
2008-09-24
影响因子：
15
通讯作者：
Gallagher, Warren H.
中科院分区：
文献类型：
--
作者：
Behling, Lee A.;Hartsel, Scott C.;Lewis, David E.;DiSpirito, Alan A.;Choi, Dong W.;Masterson, Larry R.;Veglia, Gianluigi;Gallagher, Warren H.
甲硫氨酸是一种由甲烷营养细菌产生的小分子铜结合肽，与铜的代谢密切相关，在全球碳循环中起重要作用。甲烷结核蛋白的结构由七个氨基酸和两个发色残基组成，这似乎是甲烷结核蛋白所独有的。在先前发表的结构中，两个发色残基都含有连接到羟基咪唑环上的硫代羰基。此外，一种连接在吡咯环上，另一种连接在异丙酯上。已发表的甲基丁酸乙酯的X-射线确定结构显示，这两个发色基团与具有扭曲的四面体构型的单个铜(I)离子形成N2S2结合位置。在这份报告中，我们展示了核磁共振、质谱学和化学数据，揭示了一种与以前发表的显著不同的化学结构。具体地说，1H和13C核磁共振指定与N-端异丙酯不一致，而是指向3-甲基丁酰基。我们的数据还表明，恶唑酮环而不是羟基咪唑环形成了两个生色残基的核心。由于这些环直接参与了甲烷结核蛋白与铜(I)和其他金属的结合，并可能参与了甲烷结核蛋白所显示的许多化学活动，因此它们的正确识别对于准确和详细地了解甲烷结核蛋白的许多化学和生物学作用是至关重要的。例如，恶唑酮环使甲烷杆菌蛋白在结构上与其他细菌产生的杆菌素和铁载体更相似，并为其生物合成提供了途径。
Methanobactin (mb) is a small copper-binding peptide produced by methanotrophic bacteria and is intimately involved in both their copper metabolism and their role in the global carbon cycle. The structure for methanobactin comprises seven amino acids plus two chromophoric residues that appear unique to methanobactin. In a previously published structure, both chromophoric residues contain a thiocarbonyl attached to a hydroxyimidazolate ring. In addition, one is attached to a pyrrolidine ring, while the other to an isopropyl ester. A published X-ray determined structure for methanobactin shows these two chromophoric groups forming an N2S2 binding site for a single Cu(I) ion with distorted tetrahedral geometry. In this report we show that NMR, mass spectrometry, and chemical data, reveal a chemical structure that is significantly different than the previously published one. Specifically, the 1H and 13C NMR assignments are inconsistent with an N-terminal isopropyl ester and point instead to a 3-methylbutanoyl group. Our data also indicate that oxazolone rings instead of hydroxyimidazolate rings form the core of the two chromophoric residues. Because these rings are directly involved in the binding of Cu(I) and other metals by methanobactin, and are likely involved in the many chemical activities displayed by methanobactin, their correct identity is central to developing an accurate and detailed understanding of methanobactin’s many chemical and biological roles. For example, the oxazolone rings make methanobactin structurally more similar to other bacterially produced bactins and siderophores and suggest pathways for its biosynthesis.
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影响因子：
3.9
作者：
Choi, Dong W.;Semrau, Jeremy D.;DiSpirito, Alan A.
通讯作者：
DiSpirito, Alan A.
影响因子：
15
作者：
Hakemian, AS;Tinberg, CE;Rosenzweig, AC
通讯作者：
Rosenzweig, AC
影响因子：
15
作者：
Martinho, Marlene;Choi, Dong W.;Muenck, Eckard
通讯作者：
Muenck, Eckard
DOI：
10.1073/pnas.0702879104
发表时间：
2007-07-17
影响因子：
11.1
作者：
Knapp, Charles W.;Fowle, David A.;Graham, David W.
通讯作者：
Graham, David W.
影响因子：
2.9
作者：
Kim, HJ;Galeva, N;Graham, DW
通讯作者：
Graham, DW