Systematic Structural Analyses of Attachment Organelle in Mycoplasma pneumoniae

PLoS Pathog. 2015 Dec 3;11(12):e1005299. doi: 10.1371/journal.ppat.1005299. eCollection 2015 Dec.


Mycoplasma pneumoniae, a human pathogenic bacterium, glides on host cell surfaces by a unique and unknown mechanism. It forms an attachment organelle at a cell pole as a membrane protrusion composed of surface and internal structures, with a highly organized architecture. In the present study, we succeeded in isolating the internal structure of the organelle by sucrose-gradient centrifugation. The negative-staining electron microscopy clarified the details and dimensions of the internal structure, which is composed of terminal button, paired plates, and bowl complex from the end of cell front. Peptide mass fingerprinting of the structure suggested 25 novel components for the organelle, and 3 of them were suggested for their involvement in the structure through their subcellular localization determined by enhanced yellow fluorescent protein (EYFP) tagging. Thirteen component proteins including the previously reported ones were mapped on the organelle systematically for the first time, in nanometer order by EYFP tagging and immunoelectron microscopy. Two, three, and six specific proteins localized specifically to the terminal button, the paired plates, and the bowl, respectively and interestingly, HMW2 molecules were aligned parallel to form the plate. The integration of these results gave the whole image of the organelle and allowed us to discuss possible gliding mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / metabolism
  • Microscopy, Electron, Transmission
  • Mycoplasma pneumoniae / physiology*
  • Mycoplasma pneumoniae / ultrastructure*
  • Organelles / chemistry
  • Organelles / metabolism
  • Organelles / ultrastructure*


  • Bacterial Proteins

Grant support

This work was supported by Grants-in-Aid for Scientific Research on Innovative Areas “Harmonized Supramolecular Motility Machinery and Its Diversity” (24117002 to MM and 25117530, 15H01337 to TK) and "Applied Genomics" (17019067, 18018044, 20018029 to TK) MEXT KAKENHI Grants, by Grants-in-Aid for Scientific Research (A) (21249030 to MM) and (B) (24390107 to MM) JSPS KAKENHI Grants, and by Asahi Glass Foundation and Uehara Memorial Foundation to DN. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.