Heme is a bioavailable source of iron, for which different fungi have evolved several distinct acquisition mechanisms. In the iron-scarce animal host, in particular, microbial pathogens are able to utilize the large heme pool of hemoglobin. The opportunistic pathogenic fungus Candida albicans relies on a cascade of related extracellular soluble and cell wall-anchored hemophores to extract the heme from hemoglobin and to steer it across the cell wall to the plasma membrane, where it is endocytosed into the cell. Recent crystal structure determination of the soluble C. albicans hemophore Csa2 revealed a new protein fold with a unique heme-iron coordination, which suggests distinctive functional requirements for heme binding and transfer.

血红素是生物可利用的铁源，不同的真菌已经针对其发展了几种不同的获取机制。特别是在缺铁的动物宿主中，微生物病原体能够利用血红蛋白的大量血红素库。机会致病性真菌白色念珠菌依赖于一系列相关的细胞外可溶性和细胞壁锚定的血红素，从血红蛋白中提取血红素，并将其引导穿过细胞壁到达质膜，然后被内吞进入细胞。最近对可溶性白色念珠菌的荧光团Csa2的晶体结构测定表明，新的蛋白折叠具有独特的血红素-铁配位，这暗示了血红素结合和转移的独特功能要求。