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Cryo‐electron tomography analyses of terminal organelle mutants suggest the motility mechanism of Mycoplasma genitalium
Author(s) -
Seybert Anja,
GonzalezGonzalez Luis,
Scheffer Margot P.,
LluchSenar Maria,
Mariscal Ana M.,
Querol Enrique,
Matthaeus Franziska,
Piñol Jaume,
Frangakis Achilleas S.
Publication year - 2018
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13938
Subject(s) - organelle , biology , motility , cryo electron tomography , microbiology and biotechnology , gliding motility , cytoplasm , adhesion , mycoplasma genitalium , ultrastructure , mutant , cell adhesion , electron tomography , cell , biophysics , electron microscope , biochemistry , anatomy , immunology , gene , chemistry , tomography , optics , physics , organic chemistry , scanning transmission electron microscopy , chlamydia trachomatis
Summary The terminal organelle of Mycoplasma genitalium is responsible for bacterial adhesion, motility and pathogenicity. Localized at the cell tip, it comprises an electron‐dense core that is anchored to the cell membrane at its distal end and to the cytoplasm at its proximal end. The surface of the terminal organelle is also covered with adhesion proteins. We performed cellular cryoelectron tomography on deletion mutants of eleven proteins that are implicated in building the terminal organelle, to systematically analyze the ultrastructural effects. These data were correlated with microcinematographies, from which the motility patterns can be quantitatively assessed. We visualized diverse phenotypes, ranging from mild to severe cell adhesion, motility and segregation defects. Based on our observations, we propose a double‐spring ratchet model for the motility mechanism that explains our current and previous observations. Our model, which expands and integrates the previously suggested inchworm model, allocates specific functions to each of the essential components of this unique bacterial motility system.