title: The role of Cysteine 6.47 in class A GPCRs.
abstract: BACKGROUND
  The CWxP motif of transmembrane helix 6 (x: any residue) is highly conserved in class A GPCRs. Within this motif, W6.48 is a big star in the theory of the global "toggle switch" because of its key role in the activation mechanism of GPCRs upon ligand binding. With all footlights focused on W6.48, the reason why the preceding residue, C6.47, is largely conserved is still unknown. The present study is aimed to fill up this lack of knowledge by characterizing the role of C6.47 of the CWxP motif.
  
  
  RESULTS
  A complete analysis of available crystal structures has been made alongside with molecular dynamics simulations of model peptides to explore a possible structural role for C6.47.
  
  
  CONCLUSIONS
  We conclude that C6.47 does not modulate the conformation of the TM6 proline kink and propose that C6.47 participates in the rearrangement of the TM6 and TM7 interface accompanying activation.
authors.affiliation: Departament de Biologia de Sistemes, Universitat de Vic, Vic, Barcelona 08500, Catalonia.
authors.forename: Mireia
authors.initials: M
authors.lastname: Olivella
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Caltabiano
authors.forename: Arnau
authors.initials: A
authors.lastname: Cordomí
mesh_terms: D020816:Amino Acid Motifs; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008024:Ligands; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008024:Ligands; D043562:Receptors, G-Protein-Coupled; D003545:Cysteine