Lembke Christine, Stettin Daniel, Speck Franziska, Ueberschaar Nico, De Decker Sam, Vyverman Wim, Pohnert Georg
Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, D-07743, Jena, Germany.
Laboratory of Protistology and Aquatic Ecology, Department of Biology, University Gent, Krijgslaan 281 S8, 9000, Gent, Belgium.
J Chem Ecol. 2018 Apr;44(4):354-363. doi: 10.1007/s10886-018-0944-2. Epub 2018 Mar 14.
Recently the first pheromone of a marine diatom was identified to be the diketopiperazine (S,S)-diproline. This compound facilitates attraction between mating partners in the benthic diatom Seminavis robusta. Interestingly, sexualized S. robusta cells are attracted to both the natural pheromone (S,S)-diproline as well as to its enantiomer (R,R)-diproline. Usually stereospecificity is a prerequisite for successful substrate-receptor interactions, and especially pheromone perception is often highly enantioselective. Here we introduce a structure-activity relationship study, to learn more about the principles of pheromone reception in diatoms. We analyzed the activity of nine different diketopiperazines in attraction and interference assays. The pheromone diproline itself, as well as a pipecolic acid derived diketopiperazine with two expanded aliphatic ring systems, showed the highest attractivity. Hydroxylatoin of the aliphatic rings abolished any bioactivity. Diketopiperazines derived from acyclic amino acids were not attrative as well. All stereoisomers of both the diproline and the pipecolic acid derived diketopiperazine were purified by enantioselective high-performance liquid chromatography, and application in bioactivity tests confirmed that attraction pheromone perception in this diatom is indeed not stereospecific. However, the lack of activity of diketopiperazines derived from acyclic amino acids suggests a specificity that prevents misguidance to sources of other naturally occurring diketopiperazines.
最近，一种海洋硅藻的第一种信息素被鉴定为二酮哌嗪（S,S）-二脯氨酸。这种化合物促进了底栖硅藻强壮半海链藻交配伙伴之间的吸引。有趣的是，性成熟的强壮半海链藻细胞会被天然信息素（S,S）-二脯氨酸及其对映体（R,R）-二脯氨酸所吸引。通常，立体特异性是成功的底物-受体相互作用的先决条件，尤其是信息素感知往往具有高度的对映体选择性。在此，我们开展了一项构效关系研究，以更多地了解硅藻中信息素接收的原理。我们在吸引和干扰试验中分析了九种不同二酮哌嗪的活性。信息素二脯氨酸本身，以及一种带有两个扩展脂肪环系统的哌啶酸衍生的二酮哌嗪，表现出最高的吸引力。脂肪环的羟基化消除了任何生物活性。无环氨基酸衍生的二酮哌嗪也没有吸引力。通过对映体选择性高效液相色谱法纯化了二脯氨酸和哌啶酸衍生的二酮哌嗪的所有立体异构体，生物活性测试中的应用证实，这种硅藻中的吸引信息素感知确实不是立体特异性的。然而，无环氨基酸衍生的二酮哌嗪缺乏活性表明存在一种特异性，可防止被其他天然存在的二酮哌嗪来源误导。
