Retraction for Johnston and Siderovski. Structural basis for nucleotide exchange on Gαi subunits and receptor coupling specificity.

PHARMACOLOGY Retraction for “Structural basis for nucleotide exchange on Gαi subunits and receptor coupling specificity,” by Christopher A. Johnston and David P. Siderovski, which appeared in issue 6, February 6, 2007, of Proc Natl Acad Sci USA (104:2001–2006; first published January 30, 2007; 10.1073/pnas.0608599104). The authors wish to note the following: “In our paper, a cocrystal structure at 2.2 Å resolution was described of the heterotrimeric G-protein alpha subunit Gαi1 bound to two peptides: one from an artificial sequence that promotes nucleotide exchange (KB-752) and a second peptide (D2N) from the third intracellular loop of the D2 dopamine receptor (PDB ID code 2HLB). Further examination of the unbiased electron density map has revealed that, while electron density exists for the KB752 peptide, there is a lack of clear and continuous electron density for the D2N receptor peptide in the complex. Because the structural model represents a major conclusion of the paper but is unsupported by the experimental electron density map, we wish to retract the paper. Both authors deeply regret this mistake and sincerely apologize.”