Structure and function of a 9.6 megadalton bacterial iron storage compartment
Structure and function of a 9.6 megadalton bacterial iron storage compartment
Abstract Iron storage proteins are essential for maintaining intracellular iron homeostasis and redox balance. Iron is generally stored in a soluble and bioavailable form inside ferritin protein compartments. However, some organisms do not encode ferritins and thus rely on alternative storage strategies. Encapsulins, a class of protein-based organelles, have recently been implicated in microbial iron and redox metabolism. Here, we report the structural and mechanistic characterization of a 42 nm two-component encapsulin-based iron storage compartment from Quasibacillus thermotolerans. Using cryo-electron microscopy and x-ray crystallography, we reveal the assembly principles of a thermostable T = 4 shell topology and its catalytic ferroxidase cargo. We show that the cargo-loaded compartment has an exceptionally large iron storage capacity storing over 23,000 iron atoms. These results form the basis for understanding alternate microbial strategies for dealing with the essential element iron.
Orlando B. J.、Chambers M. G.、Silver P. A.、Gardener J.、Bell D. C.、Giessen T. W.、Verdegaal A. A.、Liao M.、Birrane G.
Department of Cell Biology, Harvard Medical SchoolDepartment of Cell Biology, Harvard Medical SchoolDepartment of Systems Biology, Harvard Medical School||Wyss Institute for Biologically Inspired Engineering, Harvard UniversityCenter for Nanoscale Systems, Harvard UniversityCenter for Nanoscale Systems, Harvard University||School of Engineering and Applied Sciences, Harvard UniversityDepartment of Systems Biology, Harvard Medical School||Wyss Institute for Biologically Inspired Engineering, Harvard University||Department of Biomedical Engineering, University of MichiganDepartment of Systems Biology, Harvard Medical School||Wyss Institute for Biologically Inspired Engineering, Harvard UniversityDepartment of Cell Biology, Harvard Medical SchoolDepartment of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School
生物化学生物物理学微生物学
Orlando B. J.,Chambers M. G.,Silver P. A.,Gardener J.,Bell D. C.,Giessen T. W.,Verdegaal A. A.,Liao M.,Birrane G..Structure and function of a 9.6 megadalton bacterial iron storage compartment[EB/OL].(2025-03-28)[2025-05-11].https://www.biorxiv.org/content/10.1101/511345.点此复制
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