Membrane docking mode of the C2 domain of PKC¦Å: An infrared spectroscopy and FRET study

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• 作者：Alessio Ausili^a ; Mattias Berglin^b ; Hans Elwing^b ; Antonio L. Egea-Jimé ; nez^a ; Senena Corbalá ; n-Garc&#237 ; a^a ; Juan C. Gó ; mez-Ferná ; ndez^a ; ^{jcgomez@um.es}
• 关键词：PKC ; protein kinase C ; POPC ; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine ; POPA ; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate ; CL ; bovine heart cardiolipin ; POPE ; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine ; ATR-IR ; attenuated total internal
• 刊名：Biochimica et Biophysica Acta (BBA)/Biomembranes
• 出版年：2013
• 出版时间：February, 2013
• 年：2013
• 卷：1828
• 期：2
• 页码：552-560
• 全文大小：913 K

文摘

The C2 domain of PKC¦Å 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 ¦Â-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 ¦Â-sandwich of the PKC¦Á-C2 domain is inclined at an angle ¦Á close to 45¡ã 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 ¦Â-sheet of the C2 domain increases if compared with the secondary structure of the domain in the absence of vesicles. With respect to the ¦Â-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¡ã) smaller than that one observed when the domain interacts with vesicles of POPC/POPA (49¡ã).