Open AccessStructural transitions in the GTP cap visualized by cryo-electron microscopy of catalytically inactive microtubules
Author(s) -
Benjamin LaFrance,
Johanna Roostalu,
Gil Henkin,
B.J. Greber,
Rui Zhang,
Davide Normanno,
Chloe O. McCollum,
Thomas Surrey,
Eva Nogales
Publication year - 2022
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.2114994119
Subject(s) - gtp' , microtubule , biophysics , gtpase , bistability , crystallography , chemistry , polymerization , guanosine triphosphate , microtubule polymerization , stereochemistry , tubulin , biology , materials science , microbiology and biotechnology , biochemistry , polymer , enzyme , optoelectronics , organic chemistry
Significance Microtubules (MTs) are nonequilibrium polymers that switch between states of growth and shrinkage. This property is critical for their function and is a consequence of GTP hydrolysis in the MT. The structure of the stable GTP part of the MT (the GTP cap) has previously been inferred from MTs polymerized with nonhydrolyzable GTP analogs. Here, we report high-resolution structures of MTs truly containing GTP, polymerized from mutated, hydrolysis-deficient tubulins. We find that GTP-MTs have an “expanded lattice” and a “closed seam,” structural characteristics possibly responsible for stabilizing the GTP cap. These results provide insight into the structural transitions at growing MT ends, furthering our understanding of the bistable nature of MTs.