Anabaenopeptins are a diverse group of cyclic peptides, which contain an unusual ureido linkage. Namalides are shorter structural homologues of anabaenopeptins, which also contain an ureido linkage. The biosynthetic origins of namalides are unknown despite a strong resemblance to anabaenopeptins. Here, we show the cyanobacterium Nostoc sp. CENA543 strain producing new (nostamide B–E (2, 4, 5, and 6)) and known variants of anabaenopeptins (schizopeptin 791 (1) and anabaenopeptin 807 (3)). Surprisingly, Nostoc sp. CENA543 also produced namalide B (8) and the new namalides D (7), E (9), and F (10) in similar amounts to anabaenopeptins. Analysis of the complete Nostoc sp. CENA543 genome sequence indicates that both anabaenopeptins and namalides are produced by the same biosynthetic pathway through module skipping during biosynthesis. This unique process involves the skipping of two modules present in different nonribosomal peptide synthetases during the namalide biosynthesis. This skipping is an efficient mechanism since both anabaenopeptins and namalides are synthesized in similar amounts by Nostoc sp. CENA543. Consequently, gene skipping may be used to increase and possibly broaden the chemical diversity of related peptides produced by a single biosynthetic gene cluster. Genome mining demonstrated that the anabaenopeptin gene clusters are widespread in cyanobacteria and can also be found in tectomicrobia bacteria.

中文翻译：

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蓝藻Nostoc sp。同时生产Anabaenopeptins和Namalides 。CENA543

Anaabaenopeptins是一组不同的环状肽，其中包含不寻常的脲基键。Namalides是Anabaenopeptins的较短结构同源物，也含有脲基键。纳马利德的生物合成来源未知，尽管与anaenopepteptins非常相似。在这里，我们显示了蓝细菌Nostoc sp。CENA543菌株生产的新（nostamide B-E（2，4，5，和6））和anabaenopeptins的已知变体（schizopeptin 791（1）和anabaenopeptin 807（3））。令人惊讶的是，Nostoc sp。CENA543还生产了纳马利德B（8）和新的纳马利德D（7），E（9）和F（10）的量与Anabaenopeptins相似。完整的Nostoc sp。的分析。CENA543基因组序列表明，anaenopepteptins和namalide都是通过相同的生物合成途径通过生物合成过程中的模块跳跃而产生的。这个独特的过程涉及在纳马利德生物合成过程中跳过存在于不同非核糖体肽合成酶中的两个模块。这个跳跃是一种有效的机制，因为既anabaenopeptins和namalides以类似于用量合成发菜sp。CENA543。因此，基因跳跃可用于增加并可能拓宽由单个生物合成基因簇产生的相关肽的化学多样性。基因组挖掘表明，anaenopepteptin基因簇广泛存在于蓝细菌中，也存在于tectomicrobia细菌中。