The complete biosynthesis of the genetically encoded amino acid pyrrolysine from lysine.
The complete biosynthesis of the genetically encoded amino acid pyrrolysine from lysine.
复制标题
从赖氨酸完全生物合成遗传编码的氨基酸吡咯赖氨酸。
DOI：
10.1038/nature09918
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发表时间：
2011-03-31
期刊：
影响因子：
64.8
通讯作者：
Krzycki, Joseph A.
中科院分区：
文献类型：
--
作者：
Gaston, Marsha A.;Zhang, Liwen;Green-Church, Kari B.;Krzycki, Joseph A.
吡咯赖氨酸是在天然遗传密码中发现的第22种氨基酸，是所有已知的由甲胺形成甲烷的途径所必需的。该残基由与L-赖氨酸的ε-氨基连接的酰胺连接的甲基化吡咯啉羧酸酯组成。从不同的甲胺起始甲烷生成的三种不同的甲基转移酶具有具有被翻译为吡咯赖氨酸的框内琥珀密码子的基因。E.用产甲烷菌pylTSBCD转化大肠杆菌，可将内源生物合成的吡咯赖氨酸整合到蛋白质中。将UAG解码为吡咯赖氨酸需要产生tRNAPyl（也称为tRNACUA）的pylT和编码吡咯赖氨酰-tRNA合成酶的pylS。pylBCD基因各自是tRNA非依赖性吡咯赖氨酸合成所需的。吡咯赖氨酸是最后一种具有未知生物合成途径的遗传编码氨基酸。在这里，我们提供了一个pylBCD依赖的途径，其中吡咯赖氨酸从两个赖氨酸的遗传和质谱证据。我们表明，一个新的UAG编码的残基，去甲基吡咯赖氨酸，是由赖氨酸和外源性D-鸟氨酸在pylC，然后pylD，依赖的过程，但没有进一步转化为吡咯赖氨酸。这些结果表明，自由基S-腺苷甲硫氨酸（SAM）蛋白PylB介导赖氨酸还原反应，产生3-甲基鸟氨酸，然后在被PylD氧化产生吡咯赖氨酸之前，3-甲基鸟氨酸通过PylC连接到第二个赖氨酸分子。赖氨酸作为吡咯赖氨酸唯一前体的发现将进一步为遗传密码和氨基酸生物合成途径的进化的讨论提供信息，而该途径的中间体可能提供新的途径，通过该途径可以利用pyl系统来生产具有有用的修饰残基的重组蛋白。
Pyrrolysine, the 22nd amino acid to be found in the natural genetic code, is necessary for all known pathways of methane formation from methylamines. The residue is comprised of a methylated pyrroline carboxylate in amide linkage to the ε-amino group of L-lysine. The three different methyltransferases that initiate methanogenesis from different methylamines have genes with an in-frame amber codon translated as pyrrolysine. E. coli transformed with pylTSBCD from methanogenic Archaea can incorporate endogenously biosynthesized pyrrolysine into protein. The decoding of UAG as pyrrolysine requires pylT which produces tRNAPyl (also called tRNACUA), and pylS encoding a pyrrolysyl-tRNA synthetase. The pylBCD genes are each required for tRNA-independent pyrrolysine synthesis. Pyrrolysine has been the last remaining genetically encoded amino acid with an unknown biosynthetic pathway. Here, we provide genetic and mass spectroscopic evidence for a pylBCD-dependent pathway in which pyrrolysine arises from two lysines. We show that a new UAG encoded residue, desmethylpyrrolysine, is made from lysine and exogenous D-ornithine in a pylC, then a pylD, dependent process, but is not further converted to pyrrolysine. These results indicate that the radical S-adenosyl-methionine (SAM) protein PylB mediates a lysine mutase reaction producing 3-methylornithine, which is then ligated to a second molecule of lysine by PylC before oxidation by PylD results in pyrrolysine. The discovery of lysine as sole precursor to pyrrolysine will further inform discussions of the evolution the genetic code and amino acid biosynthetic pathways, while intermediates of the pathway may provide new avenues by which the pyl system may be exploited for production of recombinant proteins with useful modified residues.
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影响因子：
16.6
作者：
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通讯作者：
Schultz, Peter G.
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影响因子：
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