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Mycobacterium tuberculosis ferritin: a suitable workhorse protein for cryo‐EM development
Author(s) -
Gijsbers Abril,
Zhang Yue,
Gao Ye,
Peters Peter J.,
Ravelli Raimond B. G.
Publication year - 2021
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.374
H-Index - 138
ISSN - 2059-7983
DOI - 10.1107/s2059798321007233
Subject(s) - cryo electron microscopy , oligomer , mycobacterium tuberculosis , computational biology , crystallography , chemistry , nanotechnology , tuberculosis , biology , physics , materials science , biochemistry , medicine , organic chemistry , pathology
The use of cryo‐EM continues to expand worldwide and calls for good‐quality standard proteins with simple protocols for their production. Here, a straightforward expression and purification protocol is presented that provides an apoferritin, bacterioferritin B (BfrB), from Mycobacterium tuberculosis with high yield and purity. A 2.12 Å resolution cryo‐EM structure of BfrB is reported, showing the typical cage‐like oligomer constituting of 24 monomers related by 432 symmetry. However, it also contains a unique C‐terminal extension (164–181), which loops into the cage region of the shell and provides extra stability to the protein. Part of this region was ambiguous in previous crystal structures but could be built within the cryo‐EM map. These findings and this protocol could serve the growing cryo‐EM community in characterizing and pushing the limits of their electron microscopes and workflows.