Discovery of an Amphipathic Helix in a Glycosyl-Transferase Responsible of Its Membrane Adhesion

PS1 Poster session 1 Odd numbers
Location (hall): 
Start/end time: 
Monday, July 1, 2019 - 15:45 to 17:15

Xevi Biarnés, Javier Romero-García1, Antoni Planas

1Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, Barcelona, Spain

MG517 is an essential glycosyl-transferase of the pathogenic organism Mycoplasma genitalium that regulates the membrane fluidity [1]. The N-terminal region of this protein was modeled by means of homology modeling and Molecular Dynamics [2] but the structure of its C-terminal extension remains elusive. MG517 needs to be attached to the membrane in order to be active and it has been suggested that the C-terminus has an important role in this adhesion [1]. We report here a computational strategy to study this region and to find structural elements of MG517 possibly associated to membranes [3]. The combination of predictor servers and modeling has allowed us to identify a 23 residues long amphipathic helix in the apical extreme of the C-terminal extension. The membrane association process of this helix has been simulated by Molecular Dynamics and Metadynamics. We have experimentally verified that truncation of part of this helix causes a substantial reduction of glycoglycerolipids synthesis. The model proposes that MG517 recognizes and binds the diacylglycerol substrate embedded in the membrane by means of this α-helix at the C-terminus together with a previously identified binding pocket at the N-terminus [3].

  1. Andrés E, Martínez N, Planas A. J Biol Chem. 2011, 286(41):35367-79.
  2. Romero-García J, Francisco C, Biarnés X, Planas A. PLoS One. 2013. 8(12):e81990.
  3. Romero-García J, Biarnés X, Planas A. Scientific Reports 2019, 9:7085