title: Helix packing and orientation in the transmembrane dimer of gp55-P of the spleen focus forming virus.
abstract: gp55-P is a dimeric membrane protein with a single transmembrane helix that is coded by the env gene of the polycythemic strain of the spleen focus forming virus. gp55-P activates the erythropoietin (Epo) receptor through specific transmembrane helix interactions, leading to Epo-independent growth of erythroid progenitors and eventually promoting erythroleukemia. We describe the use of magic angle spinning deuterium NMR to establish the structure of the transmembrane dimer of gp55-P in model membranes. Comparison of the deuterium lineshapes of leucines in the center (Leu(396-399)) and at the ends (Leu(385), Leu(407)) of the transmembrane sequence shows that gp55-P has a right-handed crossing angle with Leu(399) packed in the dimer interface. We discuss the implications of the structure of the gp55-P transmembrane dimer for activation of the Epo receptor.
authors.affiliation: Department of Biochemistry and Cell Biology, Stony Brook University, New York 11794, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Evan
authors.initials: E
authors.lastname: Crocker
authors.forename: Stefan N
authors.initials: SN
authors.lastname: Constantinescu
authors.forename: Steven O
authors.initials: SO
authors.lastname: Smith
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D003198:Computer Simulation; D019281:Dimerization; D008565:Membrane Proteins / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared; D014759:Viral Envelope Proteins / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D008565:Membrane Proteins; D014759:Viral Envelope Proteins; C078780:glycoprotein gp55, Friend spleen focus-forming virus