8j5a
From Proteopedia
Single-particle cryo-EM structure of mouse apoferritin at 1.19 Angstrom resolution (Dataset A)
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 PubMedHydrogen bonding, bond polarity, and charges in protein molecules play critical roles in the stabilization of protein structures, as well as affecting their functions such as enzymatic catalysis, electron transfer, and ligand binding. These effects can potentially be measured in Coulomb potentials using cryogenic electron microscopy (cryo-EM). We here present charges and bond properties of hydrogen in a sub-1.2 A resolution structure of a protein complex, apoferritin, by single-particle cryo-EM. A weighted difference map reveals positive densities for most hydrogen atoms in the core region of the complex, while negative densities around acidic amino-acid side chains are likely related to negative charges. The former positive densities identify the amino- and oxo-termini of asparagine and glutamine side chains. The latter observations were verified by spatial-resolution selection and a dose-dependent frame series. The average position of the hydrogen densities depends on the parent bonded-atom type, and this is validated by the estimated level of the standard uncertainties in the bond lengths. Measurement of charges and chemical bonding in a cryo-EM structure.,Maki-Yonekura S, Kawakami K, Takaba K, Hamaguchi T, Yonekura K Commun Chem. 2023 May 31;6(1):98. doi: 10.1038/s42004-023-00900-x. PMID:37258702[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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