Gorinsky B, Horsburgh C, Lindley P F, Moss D S, Parkar M, Watson J L
Nature. 1979 Sep 13;281(5727):157-8. doi: 10.1038/281157a0.
Plasma transferrin is involved in iron transport within the circulatory system of vertebrates, and provides an iron source for haemoglobin synthesis and other metabolic requirements. However, despite extensive studies by spectroscopic, biochemical and physiological techniques, the nature of iron binding and the mechanisms of uptake and release of iron are not fully understood. Plasma transferrins are monomeric glycoproteins with a molecular weight of approximately 80,000 (ref. 2); they have two similar and very strong binding sites for Fe(III), together with two associated anion binding sites. Fragmentation studies on various transferrins have shown that the polypeptide chain is composed of two domains formed from the N-terminal and C-terminal halves of the polypeptide chain. Each domain contains one metal binding site. The marked sequence similarities which exist between the two halves may reflect a doubling of an ancestral structural gene during the phylogenetic development of the protein. Preliminary crystallographic investigations of diferric rabbit plasma transferrin have been reported from this laboratory. We now report initial studies of the X-ray structure determination of dife-ric rabbit plasma transferrin which have led to a 6-A resolution electron density map.
血浆转铁蛋白参与脊椎动物循环系统中的铁运输，并为血红蛋白合成及其他代谢需求提供铁源。然而，尽管通过光谱学、生物化学和生理学技术进行了广泛研究，但铁结合的本质以及铁的摄取和释放机制仍未完全明了。血浆转铁蛋白是分子量约为80,000的单体糖蛋白（参考文献2）；它们有两个相似且非常强的Fe(III)结合位点，以及两个相关的阴离子结合位点。对各种转铁蛋白的片段化研究表明，多肽链由多肽链的N端和C端两半形成的两个结构域组成。每个结构域包含一个金属结合位点。两半之间存在的显著序列相似性可能反映了该蛋白质在系统发育过程中祖先结构基因的加倍。本实验室已报道了二价铁兔血浆转铁蛋白的初步晶体学研究。我们现在报告二价铁兔血浆转铁蛋白X射线结构测定的初步研究，这些研究已得到分辨率为6埃的电子密度图。
