Siderophores are ferric ion-specific organic compounds that are used by bacteria and fungi to secure their iron supply when infecting target organisms. There are a few proteins in the human body, named siderocalins, which bind these important virulence factors and so starve microorganisms of iron. In this study, we analyzed in silico if serum α₁-acid glycoprotein (AAG), the major acute phase lipocalin component of the human plasma, could functionally belong to this group. The real biological function of AAG is elusive and its concentration substantially increases in response to pathological stimuli, including bacterial infections. We computationally evaluated the potential binding of nine microbial siderophores into the β-barrel cavity of AAG and compared the results with the corresponding experimental data reported for siderophore-neutrophil gelatinase-associated lipocalin complexes. According to the results, petrobactin and Fe-BisHaCam are putative candidates to be recognized by this protein. It is proposed that AAG may function as a siderophore capturing component of the innate immune system being able to neutralize bacterial iron chelators not recognized by other siderocalins.

铁载体是铁离子特异性有机化合物，细菌和真菌在感染目标生物时使用它们来确保其铁供应。人体内有几种蛋白质，称为铁钙蛋白，它们与这些重要的毒力因子结合，从而使微生物缺乏铁。在这项研究中，我们在计算机上分析了血清 α ₁α-酸性糖蛋白（AAG）是人血浆中主要的急性期脂质运载蛋白成分，在功能上可能属于这一组。AAG 的真正生物学功能是难以捉摸的，它的浓度会随着包括细菌感染在内的病理刺激而显着增加。我们通过计算评估了九种微生物铁载体与 AAG 的 β 桶腔的潜在结合，并将结果与​​报告的铁载体-中性粒细胞明胶酶相关脂质运载蛋白复合物的相应实验数据进行了比较。根据结果​​，petrobactin 和 Fe-BisHaCam 是被这种蛋白质识别的推定候选者。有人提出，AAG 可作为先天免疫系统的铁载体捕获成分，能够中和其他铁钙蛋白无法识别的细菌铁螯合剂。