植物铁蛋白结构、性质及其在纳米材料制备中的应用

铁蛋白具有储存铁及调节体内铁平衡的功能,它广泛存在于大多数生物体中.和动物铁蛋白相比,关于植物铁蛋白的研究至今很少.目前已知,植物铁蛋白主要存在于淀粉体中,而动物铁蛋白则主要存在于细胞质中.植物铁蛋白和动物铁蛋白相比,其在结构上有两个明显的特征:1.植物铁蛋白N端含有EP肽段,而动物铁蛋白则不具有.EP位于铁蛋白蛋白质外壳表面,现今发现它是作为铁蛋白第二个亚铁氧化中心,参与铁结合、氧化及种子萌发与早期生长的铁释放过程；2.在植物铁蛋白中只含有H亚基,即H-1和H-2,二者保持80％的同源性,这两个亚基在铁氧化沉淀中起着很好的协同作用. 由于铁蛋白具有特殊的结构,铁蛋白不仅可以在蛋白质内部空腔装载铁核,而且人们更多地利用脱铁铁蛋白( ApoFt)的蛋白质外壳作为载体装载其它可供利用的金属离子来装备新型生物纳米运载体系,因此植物铁蛋白在材料方面的应用也是很重要的.这篇综述主要着眼于植物铁蛋白的结构、功能及其在纳米材料方面的应用.

Structure, Function of Phytoferritin and its Application in Nano Material Science

Ferritins are a broad superfamily of iron storage proteins,present in all living organisms and play important roles in controlling cellar iron homeostasis.To date,relatively little information is available on structure and function of phytoferritin compared to animal ferritin.Phytoferritin is observed in amyloplast whereas animal ferritins are largely found in the cytoplasm of cell.In contrast to animal ferritin,phytoferritins exhibit two major distinctive features in structure:(1)phytoferritin contains a specific extension peptide(EP) at the N-terminal while animal ferritin lacks.The EP is located on the exterior surface of protein,which recently has been found to act as a second ferroxidase center for iron-binding and oxidation,and regulate iron release during the germination and early growth of seedlings.(2)only H-type subunit has been identified in phytoferritin which is usually a heteropolymer consisting of two different subunits,H-1 and H-2,sharing ~80% amino acid sequence identity.These two subunits in phytoferritin play a positively cooperative role in iron oxidative deposition in protein. The obtained ferritin has attracted great interest among researchers in the field of nanodevices due to its specific structure.Biomineralization of ferritin core has been extended to the artificial synthesis of homogeneousmetal complex nanoparticles and semiconductor nanoparticles.The inner cavity of apophytoferritin is an ideal spatially restricted chemical reaction chamber for nanoparticles synthesis.This review focuses on recent progresses in structure,function of phytoferritin and its application in nano material science.