A Major Determinant for Gliding Motility in Mycoplasma genitalium: the Interaction between the Terminal Organelle proteins MG200 and MG491 [Molecular Biophysics]

December 3rd, 2014 by Martinelli, L., Lalli, D., Garćia–Morales, L., Ratera, M., Querol, E., Pinol, J., Fita, I., Calisto, B. M.

Several mycoplasmas, such as the emergent human pathogen Mycoplasma genitalium, developed a complex polar structure, known as the Terminal Organelle (TO), responsible for a new type of cellular motility, which is involved in a variety of cell functions: cell division, adherence to host cells and virulence. The TO cytoskeleton is organised as a multi-subunit dynamic motor including three main ultra-structures: the terminal button, the electrodense core and the wheel complex. Here, we describe the interaction between MG200 and MG491, two of the main components of the TO wheel complex which connects the TO with the cell body and the cell membrane. The interaction between MG200 and MG491 has a KD in the 80 nM range as determined by Surface Plasmon Resonance (SPR). The interface between the two partners was confined to the Enriched in Aromatic and Glycine Residues (EAGR) box of MG200, previously described as a protein-protein interaction domain, and to a twenty-five residues long peptide from the C-terminal region of MG491 by SPR and NMR spectroscopy studies. An atomic description of the MG200 EAGR box binding surface was also provided by solution NMR. A M. genitalium mutant lacking the MG491 segment corresponding to the peptide reveals specific alterations in cell motility and cell morphology indicating that the MG200-MG491 interaction plays a key role in the stability and functioning of the TO.
  • Posted in Journal of Biological Chemistry, Publications
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