title: Membrane docking mode of the C2 domain of PKCε: an infrared spectroscopy and FRET study.
abstract: The C2 domain of PKCε binds to negatively charged phospholipids but little is known so far about the docking orientation of this domain when it is bound. By using a FRET assay we have studied the binding of this domain to model membranes. We have also used ATR-Fourier transform infrared spectroscopy with polarized light (ATR-FTIR) to determine the docking mode by calculating the β-sandwich orientation when the domain is bound to different types of model membranes. The vesicle lipid compositions were: POPC/POPE/POPA (22:36:42) imitating the inner leaflet of a plasma membrane, POPC/POPA (50:50) in which POPE has been eliminated with respect to the former composition and POPC/POPE/CL (43:36:21) imitating the inner mitochondrial membrane. Results show that the β-sandwich of the PKCα-C2 domain is inclined at an angle α close to 45° to the membrane normal. Some differences were found with respect to the extent of binding as a function of phospholipid composition and small changes on secondary structure were only evident when the domain was bound to model membranes of POPC/POPA: in this case, the percentage of β-sheet of the C2 domain increases if compared with the secondary structure of the domain in the absence of vesicles. With respect to the β-sandwich orientation, when the domain is bound to POPC/POPE/CL membranes it forms an angle with the normal to the surface of the lipid bilayer (39°) smaller than that one observed when the domain interacts with vesicles of POPC/POPA (49°).
authors.affiliation: Departamento de Bioquímica y Biología Molecular A, Universidad de Murcia, Apartado 4021, 30080-Murcia, Spain.
authors.forename: Alessio
authors.initials: A
authors.lastname: Ausili
authors.forename: Mattias
authors.initials: M
authors.lastname: Berglin
authors.forename: Hans
authors.initials: H
authors.lastname: Elwing
authors.forename: Antonio L
authors.initials: AL
authors.lastname: Egea-Jiménez
authors.forename: Senena
authors.initials: S
authors.lastname: Corbalán-García
authors.forename: Juan C
authors.initials: JC
authors.lastname: Gómez-Fernández
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D020404:Glycerophospholipids / Q000737:chemistry; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D051336:Mitochondrial Membranes / Q000378:metabolism; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D051744:Protein Kinase C-epsilon / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: C509561:1-palmitoyl-2-oleoyl-phosphatidyl-3-adenosine; D020404:Glycerophospholipids; D008051:Lipid Bilayers; D008055:Lipids; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010743:Phospholipids; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine; D051744:Protein Kinase C-epsilon; D000241:Adenosine; D002118:Calcium; C028694:1-palmitoyl-2-oleoylphosphatidylcholine