title: Conformational changes upon binding of a receptor loop to lipid structures: possible role in signal transduction.
abstract: The mas oncogene codes for a seven transmembrane helix protein. The amino acid sequence 253-266, from the third extracellular loop and beginning of helix 7, was synthesized either blocked or carrying an amino acid spin label at the N-terminus. Peptide binding to bilayers and micelles was monitored by ESR, fluorescence and circular dichroism. Binding induced tighter lipid packing, and caused an increase of peptide secondary structure. While binding to bilayers occurred only when peptide and phospholipid bore opposite charges, in micelles the interaction took place irrespective of charge. The results suggest that changes in lipid packing could modulate conformational changes in receptor loops related to the triggering of signal transduction.
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008823:Micelles; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D009857:Oncogenes; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013113:Spin Labels; D014364:Tryptophan
chemical_list: D003497:Cyclic N-Oxides; D008051:Lipid Bilayers; D008565:Membrane Proteins; D008823:Micelles; D009842:Oligopeptides; D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D013113:Spin Labels; D014364:Tryptophan; C037109:2,2,6,6-tetramethylpiperidine-N-oxide-4-amino-4-carboxylic acid