title: Photo-crosslinking analysis of preferential interactions between a transmembrane peptide and matching lipids.
abstract: In this study, a novel method is presented by which the molecular environment of a transmembrane peptide can be investigated directly. This was achieved by incorporating a photoactivatable crosslinking probe in the hydrophobic segment of a model transmembrane peptide. When this peptide was incorporated into lipid bilayers and irradiated with UV light, a covalent bond was formed between the crosslinking probe and a lipid. This crosslinking reaction could be visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the resulting product could be characterized by mass spectrometry. By use of phospholipases, it was demonstrated that the peptide crosslinks to both acyl chains of the lipids. The peptide showed a clear preference to partition into fluid lipids and was excluded from lipids in the gel phase. However, when the peptide was incorporated into bilayers containing two lipid species with different acyl chain lengths, molecular sorting of the lipids around the peptide based on hydrophobic matching was not observed. It is proposed that the size of the transmembrane part plays an important role in the dynamic interactions of membrane proteins with the surrounding lipids and hence in determining whether molecular sorting can occur.
authors.affiliation: Department of Biochemistry of Membranes, Center for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. A.Ridder@lrz.tum.de
authors.forename: Anja N J A
authors.initials: AN
authors.lastname: Ridder
authors.forename: Robin E J
authors.initials: RE
authors.lastname: Spelbrink
authors.forename: Jeroen A A
authors.initials: JA
authors.lastname: Demmers
authors.forename: Dirk T S
authors.initials: DT
authors.lastname: Rijkers
authors.forename: Rob M J
authors.initials: RM
authors.lastname: Liskamp
authors.forename: Josef
authors.initials: J
authors.lastname: Brunner
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
authors.forename: Ben
authors.initials: B
authors.lastname: de Kruijff
authors.forename: J Antoinette
authors.initials: JA
authors.lastname: Killian
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000595:Amino Acid Sequence; D001389:Azirines / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000138:chemical synthesis / Q000378:metabolism*; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000378:metabolism*; D010649:Phenylalanine / Q000031:analogs & derivatives; D019920:Photoaffinity Labels / Q000378:metabolism; D010777:Photochemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D014466:Ultraviolet Rays
chemical_list: D001389:Azirines; D003432:Cross-Linking Reagents; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010455:Peptides; D019920:Photoaffinity Labels; D015060:1,2-Dipalmitoylphosphatidylcholine; D010649:Phenylalanine; C044966:3-(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenyl)alanine; D004134:Dimyristoylphosphatidylcholine