Osmotin- and thaumatin-like proteins (OLPs and TLPs) have been associated with plant defense responses to different biotic stresses. In the present work, several in silico sequences from OLPs and TLPs were investigated by means of bioinformatics tools aiming to prospect for antimicrobial peptides. The peptide sequences chosen were further synthesized and characterized, and their activities and action mechanisms were assayed against some phytopathogenic fungi, bacteria and yeasts of clinical importance. From this survey approach, four peptide sequences (GDCKATSC, CPRALKVPGGCN, IVGQCPAKLKA, and CAADIVGQCPAKLK) were selected considering some chemical parameters commonly attributed to antimicrobial peptides. Antimicrobial assays showed that these peptides were unable to inhibit mycelial growth of phytopathogenic fungi and they did not affect bacterial cell growth. Nevertheless, significant inhibitory activity was found for CPRALKVPGGCN and CAADIVGQCPAKLK against Candida albicans and Saccharomyces cerevisiae. Fluorescence and scanning electron microscopy assays suggested that CAADIVGQCPAKLK did not damage the overall cell structure, or its activity was negligible on yeast membrane and cell wall integrity. However, it induced the production of reactive oxygen species (ROS) and apoptosis. Molecular docking analysis showed that CAADIVGQCPAKLK had strong affinity to interact with specific plasma membrane receptors of C. albicans and S. cerevisiae, which have been described as promoting the induction of apoptosis. The results indicate that CAADIVGQCPAKLK can be a valuable target for the development of a desired antimicrobial agent against the pathogen C. albicans.

中文翻译：

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奇异果甜蛋白植物蛋白肽通过膜受体诱导细胞凋亡表现出选择性抗念珠菌活性

Osmotin 和 thaumatin 样蛋白（OLP 和 TLP）与植物对不同生物胁迫的防御反应有关。在目前的工作中，通过旨在寻找抗菌肽的生物信息学工具研究了来自 OLP 和 TLP 的几个计算机序列。选择的肽序列被进一步合成和表征，并针对一些具有临床重要性的植物病原真菌、细菌和酵母分析了它们的活性和作用机制。根据这种调查方法，考虑到一些通常归因于抗菌肽的化学参数，选择了四种肽序列（GDCKATSC、CPRALKVPGGCN、IVGQCPAKLKA 和 CAADIVGQCPAKLK）。抗菌试验表明，这些肽不能抑制植物病原真菌的菌丝体生长，也不影响细菌细胞的生长。然而，发现 CPRALKVPGGCN 和 CAADIVGQCPAKLK 对白色念珠菌和酿酒酵母具有显着的抑制活性。荧光和扫描电子显微镜检测表明 CAADIVGQCPAKLK 不会破坏整体细胞结构，或者其对酵母膜和细胞壁完整性的活性可以忽略不计。然而，它诱导了活性氧 (ROS) 的产生和细胞凋亡。分子对接分析表明，CAADIVGQCPAKLK 与白色念珠菌和酿酒酵母的特定质膜受体具有很强的亲和力，被描述为促进细胞凋亡的诱导。