10.5452/MA-7OV95
Graziadei, Andrea; O Reilly, Francis; Xue, Liang; Mahamid, Julia; Rappsilber, Juri
Mycoplasma pneumoniae ribosome
modelarchive.org
2020
3D macromolecular model
2020-08-03
en
Structural biology performed inside cells can capture molecular machines in action within their native context. Here we developed an integrative in-cell structural approach using the genome-reduced human pathogen Mycoplasma pneumoniae. We combined whole-cell crosslinking mass spectrometry, cellular cryo-electron tomography, and integrative modeling to determine an in-cell architecture of a transcribing and translating expressome at sub-nanometer resolution. The expressome comprises RNA polymerase (RNAP), the ribosome, and the transcription elongation factors NusG and NusA. We pinpointed NusA at the interface between a NusG-bound elongating RNAP and the ribosome, and propose it can mediate transcription-translation coupling. Translation inhibition dissociated the expressome, whereas transcription inhibition stalled and rearranged it. Thus, the active expressome architecture requires both translation and transcription elongation within the cell.