Phospholamban oligomerization, quaternary structure, and sarco(endo)plasmic reticulum calcium ATPase binding measured by fluorescence resonance energy transfer in living cells.

ABSTRACT: Phospholamban (PLB) oligomerization, quaternary structure, and sarco(endo)plasmic reticulum calcium ATPase (SERCA) binding were quantified by fluorescence resonance energy transfer (FRET) in an intact cellular environment. FRET between cyan fluorescent protein-PLB and yellow fluorescent protein-PLB in AAV-293 cells showed hyperbolic dependence on protein concentration, with a maximum efficiency of 45.1 +/- 1.3%. The observed FRET corresponds to a probe separation distance of 58.7 +/- 0.5A(,) according to a computational model of intrapentameric FRET. This is consistent with models of the PLB pentamer in which cytoplasmic domains fan out from the central bundle of transmembrane helices. An I40A mutation of PLB did not alter pentamer conformation but increased the concentration of half-maxim

SUBMITTER: Kelly EM 

PROVIDER: S-EPMC2335368 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature