Binding of peptides with basic and aromatic residues to bilayer membranes: phenylalanine in the myristoylated alanine-rich C kinase substrate effector domain penetrates into the hydrophobic core of the bilayer.
Electrostatic interactions with positively charged regions of membrane-associated proteins such as myristoylated alanine-rich C kinase substrate (MARCKS) may have a role in regulating the level of free phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in plasma membranes. Both the MARCKS protein and a peptide corresponding to the effector domain (an unstructured region that contains 13 basic residues and 5 phenylalanines), MARCKS-(151-175), laterally sequester the polyvalent lipid PI(4,5)P2 in the plane of a bilayer membrane with high affinity. We used high resolution magic angle spinning NMR to establish the location of MARCKS-(151-175) in membrane bilayers, which is necessary to understand the sequestration mechanism. Measurements of cross-relaxation rates in two-dimensional nuclear Overhauser enhancement spectroscopy NMR experiments show that the five Phe rings of MARCKS-(151-175) penetrate into the acyl chain region of phosphatidylcholine bilayers containing phosphatidylglycerol or PI(4,5)P2. Specifically, we observed strong cross-peaks between the aromatic protons of the Phe rings and the acyl chain protons of the lipids, even for very short (50 ms) mixing times. The position of the Phe rings implies that the adjacent positively charged amino acids in the peptide are close to the level of the negatively charged lipid phosphates. The deep location of the MARCKS peptide in the polar head group region should enhance its electrostatic sequestration of PI(4,5)P2 by an "image charge" mechanism. Moreover, this location has interesting implications for membrane curvature and local surface pressure effects and may be relevant to a wide variety of other proteins with basic-aromatic clusters, such as phospholipase D, GAP43, SCAMP2, and the N-methyl-d-aspartate receptor.
Zhang
Wenyi
W
Department of Biochemistry and Cell Biology, Center for Structural Biology, State University of New York, Stony Brook, NY 11794-5115, USA.
Crocker
Evan
E
McLaughlin
Stuart
S
Smith
Steven O
SO
D000409:Alanine / Q000737:chemistry; D002462:Cell Membrane / Q000378:metabolism; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D008051:Lipid Bilayers / Q000378:metabolism*; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry*; D010649:Phenylalanine / Q000737:chemistry*; D010715:Phosphatidylglycerols / Q000737:chemistry; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000737:chemistry; D010739:Phospholipase D / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry; D015398:Signal Transduction
D004952:Esters; D008051:Lipid Bilayers; D008055:Lipids; D010455:Peptides; D010715:Phosphatidylglycerols; D019269:Phosphatidylinositol 4,5-Diphosphate; D016194:Receptors, N-Methyl-D-Aspartate; D010649:Phenylalanine; C002773:dimyristoylphosphatidylglycerol; D010739:Phospholipase D; D000409:Alanine; D004134:Dimyristoylphosphatidylcholine