State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, China.
School of Marine Sciences, Ningbo University, China.
FEBS Open Bio. 2021 Mar;11(3):793-803. doi: 10.1002/2211-5463.13080. Epub 2021 Feb 28.
For marine invertebrates with no adaptive immune system, ferritin is a major intracellular iron-storage protein with a critical role in innate immunity. Here, we present the crystal structures of two novel ferritins [Fer147 and Phascolosoma esculenta ferritin (PeFer)] from the marine invertebrate P. esculenta, which resides in muddy-bottom coastal regions. Fer147 and PeFer exhibit the 4-3-2 symmetry of cage-like hollow shells containing 24 subunits, similar to other known ferritins. Fer147 and PeFer contain both the conserved ferroxidase center and threefold channels. Subtle structural differences in the putative nucleation sites suggest possible routes of metal ion movement in the protein shells. However, the marked variation in the electrostatic potential of the threefold channels in Fer147 and the fourfold channels in PeFer suggests significant diversity between Fer147 and PeFer in terms of metal ion aggregation and cation exclusion. In summary, the presented crystal structures may serve as references for studies of the iron-storage mechanism of additional ferritins from marine invertebrates.
对于没有适应性免疫系统的海洋无脊椎动物，铁蛋白是一种主要的细胞内铁储存蛋白，在先天免疫中起着关键作用。在这里，我们展示了来自海洋无脊椎动物 Phascolosoma esculenta 的两种新型铁蛋白（Fer147 和 Phascolosoma esculenta 铁蛋白（PeFer））的晶体结构，它们存在于泥泞底部的沿海地区。Fer147 和 PeFer 呈现出笼状空心壳的 4-3-2 对称，包含 24 个亚基，与其他已知的铁蛋白相似。Fer147 和 PeFer 都含有保守的亚铁氧化酶中心和三通道。假定的成核位点的细微结构差异表明了在蛋白质壳中金属离子运动的可能途径。然而，Fer147 中的三通道和 PeFer 中的四通道的静电势的明显变化表明，Fer147 和 PeFer 在金属离子聚集和阳离子排斥方面存在显著差异。总之，所呈现的晶体结构可以作为来自海洋无脊椎动物的其他铁蛋白的铁储存机制研究的参考。
