Download MendeleyIn-cell discovery and characterization of a non-canonical bacterial protein translocation-folding complex.
Jensen, R.K., Xue, L., Marotta, F., Somody, J.C., Selkrig, J., Lenz, S., Rappsilber, J., Savitski, M.M., Kosinski, J., Typas, A., Zimmermann-Kogadeeva, M., Bork, P., Mahamid, J.(2026) Cell
- PubMed: 42790421 Search on PubMed
- DOI: https://doi.org/10.1016/j.cell.2026.08.055
- Primary Citation Related Structures:
9SLC, 9SLF, 9SMD - PubMed Abstract:
Cryo-electron tomography has emerged as a powerful technology for in-cell structural biology and, in combination with breakthroughs in protein structure prediction, offers a unique opportunity for illuminating functions of previously uncharacterized macromolecular complexes. Here, we used the genome-reduced bacterium Mycoplasma pneumoniae as a minimal cell model and determined in-cell maps of an unknown complex located at the cell surface. By combining proteomics, structure prediction, integrative modeling, and bioinformatics, we identified the complex to include the conserved Sec-translocon and an extracellular dome-like structure largely formed by three uncharacterized proteins (Mdps). The Mdps show structural homology to the periplasmic ATP-independent foldase PrsA, with Mdp444 retaining key catalytic residues and activity. Our study provides the first sub-nanometer-resolution maps of the complete bacterial Sec-translocation machinery, depicting its association in SecA-mediated co-translational translocation and its coordination with an extracellular protein-folding system.
- Molecular Systems Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstraße 1, 69117 Heidelberg, Germany.
Organizational Affiliation:
