9x16 | pdb_00009x16

Crystal structure of Frog M-ferritin E130A_M161Q_L165D_K168E_H169D mutant

spinqualitylabelsall models 9x16, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9x16 is a 1 chain structure with sequence from Lithobates catesbeianus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: CL, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function FRI2_AQUCT 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. Publication Abstract from PubMed Ferritins are symmetrical, hollow nanocaged iron storage proteins, which sequester and concentrate iron as a hydrated ferric oxyhydroxide (ferrihydrite) biomineral. Spontaneous self-assembly of 24 subunits in eukaryotic ferritins leads to the formation of symmetrical pores, i.e., eight hydrophilic 3-fold pores and six hydrophobic 4-fold pores. However, unlike the relatively wider 3-fold pores, which drive Fe(2+) inside, the functions of narrow 4-fold pores are relatively understudied. The current work investigates the role of 4-fold pores by gradual alterations of specific amino acids using site-directed mutagenesis, structural analysis by X-ray crystallography, and solution-based kinetic studies. Increasing the negative charge in ferritin 4-fold pore retained the cage integrity and iron-loading capability despite altering the pore structure/size/electrostatics. As additional substitutions accumulated within the same channel, the aperture widens further and the electrostatic environment became progressively more acidic around the pore lining. These gradual alterations resulted in an enhanced rate of iron mobilization (up to approximately 10-fold), possibly due to remodeling of the 4-fold (C4) pore, leading to a progressive increase in 4-fold pore diameter. Moreover, these modifications decreased cage stability, both thermally ( approximately 5 degrees C) and chemically ( approximately 3-4 folds), and increased iron-induced ferritin precipitation, similar to the case of neuroferritinopathy. Gradual Modification of Ferritin 4-Fold Pore Promotes Cage Instability, Fe(2+) Exit, and Iron-Induced Protein Precipitation.,Subhadarshanee B, Jagdev MK, Bhattacharyya G, Parida A, Mohanty A, Vasudevan D, Behera RK Biochemistry. 2026 Mar 3;65(5):614-625. doi: 10.1021/acs.biochem.5c00744. Epub , 2026 Feb 17. PMID:41700891 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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