Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Proc Natl Acad Sci U S A. 2010 Jun 8;107(23):10430-5. doi: 10.1073/pnas.0913677107. Epub 2010 May 17.
Our understanding of secondary metabolite production in bacteria has been shaped primarily by studies of attached varieties such as symbionts, pathogens, and soil bacteria. Here we show that a strain of the single-celled, planktonic marine cyanobacterium Prochlorococcus-which conducts a sizable fraction of photosynthesis in the oceans-produces many cyclic, lanthionine-containing peptides (lantipeptides). Remarkably, in Prochlorococcus MIT9313 a single promiscuous enzyme transforms up to 29 different linear ribosomally synthesized peptides into a library of polycyclic, conformationally constrained products with highly diverse ring topologies. Genes encoding this system are found in variable abundances across the oceans-with a hot spot in a Galapagos hypersaline lagoon-suggesting they play a habitat- and/or community-specific role. The extraordinarily efficient pathway for generating structural diversity enables these cyanobacteria to produce as many secondary metabolites as model antibiotic-producing bacteria, but with much smaller genomes.
我们对细菌次生代谢产物生产的理解主要是通过对附着菌（如共生菌、病原体和土壤细菌）的研究形成的。在这里，我们展示了一种单细胞浮游海洋蓝细菌——海洋中进行大量光合作用的聚球藻——产生许多环状、含硫氨酸的肽（硫肽）。值得注意的是，在聚球藻 MIT9313 中，一种单一的混杂酶将多达 29 种不同的线性核糖体合成肽转化为一个具有高度多样化环拓扑结构的多环、构象受限产物库。编码该系统的基因在海洋中丰度不同——在加拉帕戈斯高盐泻湖中存在一个热点——表明它们在特定的栖息地和/或群落中发挥作用。生成结构多样性的极高效率途径使这些蓝细菌能够产生与模型抗生素产生细菌一样多的次生代谢产物，但基因组要小得多。
