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Molecular structure of mouse apoferritin resolved at 2.7 Angstroms with the Glacios cryo-microscope
Structural highlights
FunctionFRIH_MOUSE Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Has ferroxidase activity. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation. Also plays a role in delivery of iron to cells. Mediates iron uptake in capsule cells of the developing kidney.[1] Publication Abstract from PubMedHere we present the structure of mouse H-chain apoferritin at 2.7 A (FSC = 0.143) solved by single particle cryogenic electron microscopy (cryo-EM) using a 200 kV device, the Thermo Fisher Glacios(R). This is a compact, two-lens illumination system with a constant power objective lens, without any energy filters or aberration correctors, often thought of as a "screening cryo-microscope". Coulomb potential maps reveal clear densities for main chain carbonyl oxygens, residue side chains (including alternative conformations) and bound solvent molecules. We used a quasi-crystallographic reciprocal space approach to fit model coordinates to the experimental cryo-EM map. We argue that the advantages offered by (a) the high electronic and mechanical stability of the microscope, (b) the high emission stability and low beam energy spread of the high brightness Field Emission Gun (X-FEG), (c) direct electron detection technology and (d) particle-based Contrast Transfer Function (CTF) refinement have contributed to achieving high resolution. Overall, we show that basic electron optical settings for automated cryo-electron microscopy imaging can be used to determine structures approaching atomic resolution. 2.7 A cryo-EM structure of vitrified M. musculus H-chain apoferritin from a compact 200 keV cryo-microscope.,Hamdi F, Tuting C, Semchonok DA, Visscher KM, Kyrilis FL, Meister A, Skalidis I, Schmidt L, Parthier C, Stubbs MT, Kastritis PL PLoS One. 2020 May 6;15(5):e0232540. doi: 10.1371/journal.pone.0232540., eCollection 2020. PMID:32374767[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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