Deciphering the role of individual acyl chains in the interaction network between phosphatidylserines and a single-spanning membrane protein.
PMP1 is a small single-spanning membrane protein functioning as a regulatory subunit of the yeast plasma membrane H(+)-ATPase. This protein forms a unique helix and exhibits a positively charged cytoplasmic domain that is able to specifically segregate phosphatidylserines (PSs). A marked groove formed at the helix surface is thought to play a major role in the related lipid-protein interaction network. Mutational analysis and (1)H NMR experiments were therefore performed on a synthetic PMP1 fragment using DPC-d(38) micelles as a membrane-like environment, in the presence of small amounts of POPS. A mutation designed for altering the helix groove was shown to disfavor the POPS binding specificity as much as that affecting the electrostatic interaction network. From POPS titration experiments monitored by a full set of one- and two-dimensional NOESY spectra, the association between the phospholipids and the PMP1 peptide has been followed. Our data reveal that the clustering of POPS molecules is promoted from a stabilized framework obtained by coupling the PMP1 helix groove to a POPS sn-2 chain. To our knowledge, the NOE-based titration plots displayed in this report constitute the first NMR data that directly distinguish the role of the sn-1 and sn-2 acyl chains in a lipid-protein interaction. The results are discussed while taking into account our accurate knowledge of the yeast plasma membrane composition and its ability to form functional lipid rafts.
Mousson
Florence
F
Service de Biophysique des Fonctions Membranaires, CEA DSV/DBJC and URA CNRS 2096, Centre d'Etudes de Saclay, 91191 Gif sur Yvette Cedex, France.
Coïc
Yves-Marie
YM
Baleux
Françoise
F
Beswick
Veronica
V
Sanson
Alain
A
Neumann
Jean-Michel
JM
D000596:Amino Acids / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008823:Micelles; D008956:Models, Chemical; D009154:Mutation; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011510:Proteolipids / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006180:Proton-Translocating ATPases; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D000596:Amino Acids; D005656:Fungal Proteins; D008051:Lipid Bilayers; D008055:Lipids; D008565:Membrane Proteins; D008823:Micelles; D009419:Nerve Tissue Proteins; C489077:PMP1 protein, S cerevisiae; D010446:Peptide Fragments; D010718:Phosphatidylserines; D011510:Proteolipids; D029701:Saccharomyces cerevisiae Proteins; D006180:Proton-Translocating ATPases