7oe2
From Proteopedia
Model of closed pentamer of the Haliangium ochraceum encapsulin from symmetry expansion of icosahedral single particle reconstruction
Structural highlights
FunctionFER_HALO1 Cargo protein of a type 1 encapsulin nanocompartment. A ferritin-like ferroxidase that converts Fe(2+) to Fe(3+) iron inside the encapsulin nanocompartment (PubMed:30837306, PubMed:35080974). Mineralized Fe(3+) is released to the exterior of the decameric complex for deposition in the encapsulin nanocompartment. In solution the decamer binds 10-15 iron cations; in the encapsulin nanocompartment the decamer can bind up to 48 ions, perhaps via its internal channel, and on its exterior. The cargo-loaded nanocompartment maximally sequesters up to 4150 Fe ions (By similarity).[UniProtKB:Q2RVS1][1] [2] Publication Abstract from PubMedEncapsulins are protein nanocompartments that house various cargo enzymes, including a family of decameric ferritin-like proteins. Here, we study a recombinant Haliangium ochraceum encapsulin:encapsulated ferritin complex using cryo-electron microscopy and hydrogen/deuterium exchange mass spectrometry to gain insight into the structural relationship between the encapsulin shell and its protein cargo. An asymmetric single-particle reconstruction reveals four encapsulated ferritin decamers in a tetrahedral arrangement within the encapsulin nanocompartment. This leads to a symmetry mismatch between the protein cargo and the icosahedral encapsulin shell. The encapsulated ferritin decamers are offset from the interior face of the encapsulin shell. Using hydrogen/deuterium exchange mass spectrometry, we observed the dynamic behavior of the major fivefold pore in the encapsulin shell and show the pore opening via the movement of the encapsulin A-domain. These data will accelerate efforts to engineer the encapsulation of heterologous cargo proteins and to alter the permeability of the encapsulin shell via pore modifications. Pore dynamics and asymmetric cargo loading in an encapsulin nanocompartment.,Ross J, McIver Z, Lambert T, Piergentili C, Bird JE, Gallagher KJ, Cruickshank FL, James P, Zarazua-Arvizu E, Horsfall LE, Waldron KJ, Wilson MD, Mackay CL, Basle A, Clarke DJ, Marles-Wright J Sci Adv. 2022 Jan 28;8(4):eabj4461. doi: 10.1126/sciadv.abj4461. Epub 2022 Jan, 26. PMID:35080974[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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