Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
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Cardiolipin (CL) and related diphosphatidyl lipids are hardly accessible because of the complexity of their chemical synthesis. In the present paper, the transphosphatidylation reaction catalyzed by phospholipase D (PLD) from Streptomyces sp. has been proven as an alternative enzyme-assisted strategy for the synthesis of new CL analogs. The formation of this type of compounds from phosphatidylcholine was compared for a series of N- and C2-substituted ethanolamine derivatives as well as non-charged alcohols such as glycerol and ethylene glycol. The rapid exchange of the choline head group by ethanolamine derivatives having a low molecular volume (diethanolamine and serinol) gave rise to an efficient production of the corresponding CL analogs. In contrast, the yields were comparably low in the reaction with bulky nitrogenous acceptor alcohols (triethanolamine, tris(hydroxymethyl)aminomethane, tetrakis(hydroxyethyl)ammonium) or the non-charged alcohols. Therefore, a strong dependence of the conversion of the monophosphatidyl to the diphosphatidyl compound on steric parameters and the head group charge was concluded. The enzyme-assisted strategy was used for the preparation of purified diphosphatidyldiethanolamine and diphosphatidylserinol.
Publikation
Chen, Y.; Liu, P.; Hoehenwarter, W.; Lin, J.;Proteomic and Phosphoproteomic Analysis of Picea wilsonii Pollen Development under Nutrient LimitationJ. Proteome Res.114180-4190(2012)DOI: 10.1021/pr300295m
The pollen tube is a tip-growing system that delivers sperm to the ovule and thus is essential for sexual plant reproduction. Sucrose and other microelements act as nutrients and signaling molecules through pathways that are not yet fully understood. Taking advantage of high-throughput liquid chromatography coupled to mass spectrometry (LC-MS), we performed a label-free shotgun proteomic analysis of pollen in response to nutrient limitation using mass accuracy precursor alignment. We compared 168 LC-MS analyses and more than 1 million precursor ions and could define the proteomic phenotypes of pollen under different conditions. In total, 166 proteins and 42 phosphoproteins were identified as differentially regulated. These proteins are involved in a variety of signaling pathways, providing new insights into the multifaceted mechanism of nutrient function. The phosphorylation of proteins involved in cytoskeleton dynamics was found to be specifically responsive to Ca2+ and sucrose deficiency, suggesting that sucrose and extracellular Ca2+ influx are necessary for the maintenance of cytoskeleton polymerization. Sucrose limitation leads to widespread accumulation of proteins involved in carbohydrate metabolism and protein degradation. This highlights the wide range of metabolic and cellular processes that are modulated by sucrose but complicates dissection of the signaling pathways.