Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
FEBS Lett. 2011 Sep 2;585(17):2627-34. doi: 10.1016/j.febslet.2011.07.038. Epub 2011 Aug 4.
Silica glass formation in diatoms requires the biosynthesis of unusual, very long chain polyamines (LCPA) composed of iterated aminopropyl units. Diatoms processively synthesize LCPA, N-methylate the amine groups and transfer concatenated, N-dimethylated aminopropyl groups to silaffin proteins. Here I show that diatom genomes possess signal peptide-containing gene fusions of bacterially-derived polyamine biosynthetic enzymes S-adenosylmethionine decarboxylase (AdoMetDC) and an aminopropyltransferase, sometimes fused to a eukaryotic histone N-methyltransferase domain, that potentially synthesize and N-methylate LCPA. Fusions of similar, alternatively configured domains but with a catalytically dead AdoMetDC and in one case a Tudor domain, may N-dimethylate and transfer multiple aminopropyl unit polyamines onto silaffin proteins.
硅藻的硅玻璃形成需要合成由重复的氨丙基单元组成的不寻常的、非常长链聚胺（LCPA）。硅藻进行性地合成 LCPA，将胺基团 N-甲基化，并将串联的、N-二甲基化的氨丙基基团转移到硅蛋白上。在这里，我表明硅藻基因组具有包含信号肽的基因融合，这些融合了细菌来源的聚胺生物合成酶 S-腺苷甲硫氨酸脱羧酶（AdoMetDC）和氨丙基转移酶，有时融合了真核组蛋白 N-甲基转移酶结构域，可能合成并 N-甲基化 LCPA。具有类似的、替代构型的结构域，但具有催化失活的 AdoMetDC，在一种情况下还具有 Tudor 结构域，可能将多个氨丙基单元聚胺 N-二甲基化并转移到硅蛋白上。
