FUNGAL FERRITINS

作为相对简单的真核生物，真菌似乎具有 它们的铁代谢与其他微生物 (原核生物)系统以及高等真核生物的系统。 因此，对它的研究可以告诉我们一些进化的东西 铁代谢的研究进展以及提供一个更简单的模型 哺乳动物铁的运输、储存和调控。在……里面 此外，我们计划研究的接合菌类真菌， 含有许多人类真菌病原体，因此更详细 了解它们新陈代谢的这一重要部分可能会导致 治疗方面的进展。在我们的前期工作中，有两个截然不同的 已鉴定出类铁蛋白含铁蛋白，并 一种是从尖刺假单胞菌中分离出来的；一种是从孢子和 另一种来自菌丝体。菌丝体蛋白已被提纯 由钙的两个亚基组成。20kD相对分子质量。基座 关于血红素谱的存在和高度序度 同源性发现，确定了菌丝体蛋白是一种 细菌铁蛋白。这是第一个演示 细菌铁蛋白真核生物中细菌铁蛋白的存在孢子 蛋白质还没有被纯化到均一，但它是不同的 经凝胶电泳法测得的菌丝体铁蛋白，没有出现 含有亚铁血红素，并具有穆斯堡尔参数 像铁蛋白核心一样的“哺乳动物”。我们计划分离编码基因 对于这两种形式的真菌铁蛋白，过度表达它们并进行研究 它们的一些生物物理性质与铁核有关 队形。观察到“细菌”型和 “常规”类型的铁蛋白都存在于真菌中，但在 不同的发展形式也为详细研究开辟了道路 这两种蛋白质的功能和调节方式 在其他种类的生物体中是不可能的。

As relatively simple eukaryotes, fungi appear to have aspects to their iron metabolism that are related to both other microbial (prokaryotic) systems as well as those of the higher eukaryotes. Thus its study can tell us something of the evolutionary development of iron metabolism as well as providing a simpler model of mammalian iron transport and storage and regulation. In addition, the Zygomycetes group of fungi that we plan to study, contains a number of human fungal pathogens hence a more detailed knowledge of this important part of their metabolism may lead to advances in therapy. In our preliminary work, two distinct ferritin-like iron containing proteins have been identified and isolated from the fungus Absidia spinosa; one from the spores and another from the mycelia. The mycelial protein has been purified and consists of two subunits of Ca. 20 kD molecular weight. Based on the presence of a heme spectrum and the high degree of sequence homology found, it is established that the mycelial protein is a bacterioferritin. This is the first example demonstrating the presence of a bacterioferritin in a eukaryotic organism. The spore protein has not yet been purified to homogeneity but it is distinct by gel electrophoresis from the mycelial ferritin, does not appear to contain heme, and has Mossbauer parameters suggestive of a "mammalian" like ferritin core. We plan to isolate the genes coding for both forms of the fungal ferritins, overexpress them and study some of their biophysical properties related to iron core formation. The observation that the "bacterio" type and "conventional" types of ferritin both exist in fungi but in different developmental forms also opens the way for detailed study of the function and regulation of these two proteins in a way that has not been possible in other classes of organisms.