The structural topology of wild-type phospholamban in oriented lipid bilayers using 15N solid-state NMR spectroscopy.
For the first time, 15N solid-state NMR experiments were conducted on wild-type phospholamban (WT-PLB) embedded inside mechanically oriented phospholipid bilayers to investigate the topology of its cytoplasmic and transmembrane domains. 15N solid-state NMR spectra of site-specific 15N-labeled WT-PLB indicate that the transmembrane domain has a tilt angle of 13 degrees+/-6 degrees with respect to the POPC (1-palmitoyl-2-oleoyl-sn-glycero-phosphocholine) bilayer normal and that the cytoplasmic domain of WT-PLB lies on the surface of the phospholipid bilayers. Comparable results were obtained from site-specific 15N-labeled WT-PLB embedded inside DOPC/DOPE (1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) mechanically oriented phospholipids' bilayers. The new NMR data support a pinwheel geometry of WT-PLB, but disagree with a bellflower structure in micelles, and indicate that the orientation of the cytoplasmic domain of the WT-PLB is similar to that reported for the monomeric AFA-PLB mutant.
Abu-Baker
Shadi
S
Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
Lu
Jun-Xia
JX
Chu
Shidong
S
Shetty
Kiran K
KK
Gor'kov
Peter L
PL
Lorigan
Gary A
GA
D002135:Calcium-Binding Proteins / Q000737:chemistry*; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D009154:Mutation; D009587:Nitrogen Isotopes / Q000737:chemistry; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D000099211:Phospholamban
D002135:Calcium-Binding Proteins; D008051:Lipid Bilayers; D009587:Nitrogen Isotopes; D010713:Phosphatidylcholines; D010743:Phospholipids; D000099211:Phospholamban; C028694:1-palmitoyl-2-oleoylphosphatidylcholine