The role of hydrophobic matching on transmembrane helix packing in cells
Grau, Brayan; Javanainen, Matti; Jesus Garcia-Murria, Maria; Kulig, Waldemar; Vattulainen, Ilpo; Mingarro, Ismael; Martinez-Gil, Luis (2017)
Avaa tiedosto
Lataukset:
Grau, Brayan
Javanainen, Matti
Jesus Garcia-Murria, Maria
Kulig, Waldemar
Vattulainen, Ilpo
Mingarro, Ismael
Martinez-Gil, Luis
2017
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201712202446
https://urn.fi/URN:NBN:fi:tty-201712202446
Kuvaus
Peer reviewed
Tiivistelmä
Folding and packing of membrane proteins are highly influenced by the lipidic component of the membrane. Here, we explore how the hydrophobic mismatch (the difference between the hydrophobic span of a transmembrane protein region and the hydrophobic thickness of the lipid membrane around the protein) influences transmembrane helix packing in a cellular environment. Using a ToxRED assay in Escherichia coli and a Bimolecular Fluorescent Complementation approach in human-derived cells complemented by atomistic molecular dynamics simulations we analyzed the dimerization of Glycophorin A derived transmembrane segments. We concluded that, biological membranes can accommodate transmembrane homo-dimers with a wide range of hydrophobic lengths. Hydrophobic mismatch and its effects on dimerization are found to be considerably weaker than those previously observed in model membranes, or under in vitro conditions, indicating that biological membranes (particularly eukaryotic membranes) can adapt to structural deformations through compensatory mechanisms that emerge from their complex structure and composition to alleviate membrane stress. Results based on atomistic simulations support this view, as they revealed that Glycophorin A dimers remain stable, despite of poor hydrophobic match, using mechanisms based on dimer tilting or local membrane thickness perturbations. Furthermore, hetero-dimers with large length disparity between their monomers are also tolerated in cells, and the conclusions that one can draw are essentially similar to those found with homo-dimers. However, large differences between transmembrane helices length hinder the monomer/dimer equilibrium, confirming that, the hydrophobic mismatch has, nonetheless, biologically relevant effects on helix packing in vivo.
Kokoelmat
- TUNICRIS-julkaisut [19239]