Partida-Hanon Angélica, Maestro-López Moisés, Vitale Stefania, Turrà David, Di Pietro Antonio, Martínez-Del-Pozo Álvaro, Bruix Marta
Department of Biological Physical Chemistry, Institute of Physical Chemistry Rocasolano, CSIC, Madrid, Spain.
Department of Biochemistry and Molecular Biology, Faculty of Chemistry, Complutense University, Madrid, Spain.
Front Microbiol. 2020 Jun 5;11:1090. doi: 10.3389/fmicb.2020.01090. eCollection 2020.
is a highly destructive plant pathogen and an emerging pathogen of humans. Like other ascomycete fungi, secretes α-pheromone, a small peptide that functions both as a chemoattractant and as a quorum-sensing signal. Three of the ten amino acid residues of α-pheromone are tryptophan, an amino acid whose sidechain has high affinity for lipid bilayers, suggesting a possible interaction with biological membranes. Here we tested the effect of different lipid environments on α-pheromone structure and function. Using spectroscopic and calorimetric approaches, we show that this peptide interacts with negatively charged model phospholipid vesicles. Fluorescence emission spectroscopy and nuclear magnetic resonance (NMR) measurements revealed a key role of the positively charged groups and Trp residues. Furthermore, NMR-based calculation of the 3D structure in the presence of micelles, formed by lipid surfactants, suggests that α-pheromone can establish an intramolecular disulfide bond between the two cysteine residues during interaction with membranes, but not in the absence of lipid mimetics. Remarkably, this oxidized version of α-pheromone lacks biological activity as a chemoattractant and quorum-sensing molecule. These results suggest the presence of a previously unidentified redox regulated control of α-pheromone activity at the surface of the plasma membrane that could influence the interaction with its cognate G-protein coupled receptor.
是一种极具破坏性的植物病原体，也是一种新出现的人类病原体。与其他子囊菌真菌一样，它分泌α-信息素，这是一种小肽，兼具化学引诱剂和群体感应信号的功能。α-信息素的十个氨基酸残基中有三个是色氨酸，这种氨基酸的侧链对脂质双层具有高亲和力，这表明它可能与生物膜相互作用。在这里，我们测试了不同脂质环境对α-信息素结构和功能的影响。使用光谱学和量热法，我们表明这种肽与带负电荷的模型磷脂囊泡相互作用。荧光发射光谱和核磁共振（NMR）测量揭示了带正电荷基团和色氨酸残基的关键作用。此外，基于NMR对由脂质表面活性剂形成的胶束存在下的三维结构计算表明，α-信息素在与膜相互作用期间可以在两个半胱氨酸残基之间建立分子内二硫键，但在没有脂质模拟物的情况下则不能。值得注意的是，这种氧化形式的α-信息素作为化学引诱剂和群体感应分子缺乏生物活性。这些结果表明在质膜表面存在一种以前未被识别的α-信息素活性的氧化还原调节控制，这可能会影响其与同源G蛋白偶联受体的相互作用。
