Phospholamban (PLB) is an integral membrane protein regulating Ca(2+) transport 
through inhibitory interaction with sarco(endo)plasmic reticulum calcium ATPase 
(SERCA). The Asn27 to Ala (N27A) mutation of PLB has been shown to function as a 
superinhibitor of the affinity of SERCA for Ca(2+) and of cardiac contractility 
in vivo. The effects of this N27A mutation on the side-chain and backbone 
dynamics of PLB were investigated with (2)H and (15)N solid-state NMR 
spectroscopy in phospholipid multilamellar vesicles (MLVs). (2)H and (15)N NMR 
spectra indicate that the N27A mutation does not significantly change the 
side-chain or backbone dynamics of the transmembrane and cytoplasmic domains 
when compared to wild-type PLB. However, dynamic changes are observed for the 
hinge region, in which greater mobility is observed for the CD(3)-labeled Ala24 
N27A-PLB. The increased dynamics in the hinge region of PLB upon N27A mutation 
may allow the cytoplasmic helix to more easily interact with the Ca(2+)-ATPase; 
thus, showing increased inhibition of Ca(2+)-ATPase.