Department of Microbiology, Institute of Biology, University of Białystok, Swierkowa 20B, 15-950 Białystok, Poland.
Pol J Microbiol. 2010;59(1):3-10.
Cereulide produced by Bacillus cereus sensu stricto and valinomycin synthesized mainly by Streptomyces spp. are natural dodecadepsipeptide ionophores that act as potassium transporters. Moreover, they comprise three repetitions of similar tetrapeptide motifs synthesized by nonribosomal peptide synthesis complexes. Resemblances in their structure find their reflections in the same way of action. The toxicity of valinomycin and cereulide is an effect of the disturbance of ionic equilibrium and transmembrane potential that may influence the whole organism and then cause fatal consequences. The vlm and ces operons encoding valinomycin and cereulide are both composed of two large, similar synthetase genes, one thioestrase gene and four other ORFs with unknown activities. In spite of the characterization of valinomycin and cereulide, genetic determinants encoding their biosynthesis have not yet been clarified.
由蜡样芽孢杆菌严格意义上产生的cereulide 和主要由链霉菌属合成的 valinomycin 是天然的十二肽离子载体，作为钾转运体起作用。此外，它们由非核糖体肽合成复合物合成的三个相似的四肽基序重复组成。它们在结构上的相似之处反映在相同的作用方式上。valinomycin 和 cereulide 的毒性是离子平衡和跨膜电位紊乱的结果，可能会影响整个生物体，然后导致致命的后果。编码 valinomycin 和 cereulide 的 vlm 和 ces 操纵子均由两个大型、相似的合成酶基因、一个硫酯酶基因和四个具有未知活性的其他 ORF 组成。尽管已经对 valinomycin 和 cereulide 进行了表征，但编码它们生物合成的遗传决定因素尚未阐明。
