Pore dynamics and asymmetric cargo loading in an encapsulin nanocompartment
Jennifer Ross, Zak McIver, Thomas Lambert, Cecilia Piergentili, Jasmine Emma Bird, Kelly J. Gallagher, Faye L. Cruickshank, P. W. James, Efrain Zarazúa-Arvizu, Louise Horsfall, Kevin J. Waldron, Marcus D. Wilson, C. Logan Mackay, Arnaud Baslé, David J. Clarke, Jon Marles‐Wright
Abstract
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.