title: MgF(3)(-) as a transition state analog of phosphoryl transfer.
abstract: The formation of complexes between small G proteins and certain of their effectors can be facilitated by aluminum fluorides. Solution studies suggest that magnesium may be able to replace aluminum in such complexes. We have determined the crystal structure of RhoA.GDP bound to RhoGAP in the presence of Mg(2+) and F(-) but without Al(3+). The metallofluoride adopts a trigonal planar arrangement instead of the square planar structure of AlF(4)(-). We have confirmed that these crystals contain magnesium and not aluminum by proton-induced X-ray emission spectroscopy. The structure adopted by GDP.MgF(-) possesses the stereochemistry and approximate charge expected for the transition state. We suggest that MgF3(-) may be the reagent of choice for studying phosphoryl transfer reactions.
authors.affiliation: Computational & Structural Sciences, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Herts, United Kingdom.
authors.forename: Debbie L
authors.initials: DL
authors.lastname: Graham
authors.forename: Peter N
authors.initials: PN
authors.lastname: Lowe
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: Grime
authors.forename: Michael
authors.initials: M
authors.lastname: Marsh
authors.forename: Katrin
authors.initials: K
authors.lastname: Rittinger
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Smerdon
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Gamblin
authors.forename: John F
authors.initials: JF
authors.lastname: Eccleston
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry*; D006153:Guanosine Diphosphate / Q000737:chemistry; D017616:Magnesium Compounds / Q000737:chemistry*; D008958:Models, Molecular; D010758:Phosphorus / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D020741:rho GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D017607:Aluminum Compounds; D017616:Magnesium Compounds; D006153:Guanosine Diphosphate; D010758:Phosphorus; C031288:magnesium fluoride; D020741:rho GTP-Binding Proteins; D005459:Fluorides; C032311:aluminum fluoride