2M3B: Serine 16 phosphorylated phospholamban pentamer, Hybrid solution and solid-state NMR structural ensemble

Phospholamban (PLN) inhibits the sarco(endo)plasmic reticulum Ca(2)(+)-ATPase (SERCA), thereby regulating cardiac diastole. In membranes, PLN assembles into homopentamers that in both the phosphorylated and nonphosphorylated states have been proposed to form ion-selective channels. Here, we determined the structure of the phosphorylated pentamer using a combination of solution and solid-state nuclear magnetic resonance methods. We found that the pinwheel architecture of the homopentamer is preserved upon phosphorylation, with each monomer having an L-shaped conformation. The TM domains form a hydrophobic pore approximately 24 A long and 2 A in diameter, which is inconsistent with canonical Ca(2)(+)-selective channels. Phosphorylation, however, enhances the conformational dynamics of the cytoplasmic region of PLN, causing partial unwinding of the amphipathic helix. We propose that PLN oligomers act as storage for active monomers, keeping SERCA function within a physiological window.
PDB ID: 2M3BDownload
MMDB ID: 114572
PDB Deposition Date: 2013/1/15
Updated in MMDB: 2013/12
Experimental Method:
solution nmr; solid-state nmr
Source Organism:
Similar Structures:
Biological Unit for 2M3B: pentameric; determined by author
Molecular Components in 2M3B
Label Count Molecule
Proteins (5 molecules)
Cardiac Phospholamban(Gene symbol: PLN)
Molecule annotation
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Citing MMDB