DataSheet_1_Iron Deprivation Modulates the Exoproteome in Paracoccidioides brasiliensis.pdf

Fungi of the Paracoccidioides genus are the etiological agents of the systemic mycosis paracoccidioidomycosis and, when in the host, they find a challenging environment that is scarce in nutrients and micronutrients, such as Fe, which is indispensable for the survival of the pathogen. Previous studies have shown that fungi of this genus, in response to Fe deprivation, are able to synthesize and capture siderophores (Fe3+ chelators), use Fe-containing host proteins as a source of the metal, and use a non-canonical reductive pathway for Fe3+ assimilation. Despite all of these findings, there are still gaps that need to be filled in the pathogen response to metal deprivation. To contribute to the knowledge related to this subject, we obtained the exoproteome of Paracoccidioides brasiliensis (Pb18) undergoing Fe deprivation and by nanoUPLC-MSE. One hundred forty-one proteins were identified, and out of these, 64 proteins were predicted to be secreted. We also identified the regulation of several virulence factors. Among the results, we highlight Cyb5 as a secreted molecule of Paracoccidioides in the exoproteome obtained during Fe deprivation. Cyb5 is described as necessary for the Fe deprivation response of Saccharomyces cerevisiae and Aspergillus fumigatus. Experimental data and molecular modeling indicated that Cyb5 can bind to Fe ions in vitro, suggesting that it can be relevant in the arsenal of molecules related to iron homeostasis in P. brasiliensis.

副球孢子菌属（Paracoccidioides）真菌是系统性真菌病副球孢子菌病的病原菌。当侵入宿主后，它们会面临营养物质及微量营养素（如铁Fe）匮乏的严苛环境，而铁离子正是该病原菌生存不可或缺的元素。既往研究表明，该属真菌在铁匮乏条件下，可合成并捕获铁载体（siderophores，三价铁螯合剂Fe³+ chelators），利用宿主来源的含铁蛋白获取铁元素，并通过非经典还原途径完成三价铁的同化作用。尽管已有上述研究成果，但该病原菌应对金属匮乏的分子机制仍存在诸多有待填补的研究空白。为丰富该领域的相关研究认知，本研究通过纳升级超高效液相色谱-质谱联用法（nanoUPLC-MSE），获取了铁匮乏条件下巴西副球孢子菌（Paracoccidioides brasiliensis，Pb18）的分泌蛋白组（exoproteome）。本研究共鉴定得到141种蛋白质，其中64种经生物信息学预测为分泌型蛋白。同时，本研究还鉴定到多种毒力因子的调控表达情况。在本次研究结果中，我们重点关注到Cyb5作为副球孢子菌的分泌型分子，存在于铁匮乏条件下获取的分泌蛋白组中。已有研究表明，Cyb5是酿酒酵母（Saccharomyces cerevisiae）与烟曲霉（Aspergillus fumigatus）应对铁匮乏反应的必需分子。实验数据与分子模拟结果显示，Cyb5在体外可结合铁离子，这提示该分子可能参与巴西副球孢子菌中铁稳态相关的分子功能网络。