title: Molecular complementarity between tetracycline and the GTPase active site of elongation factor Tu.
abstract: Two crystal forms of a complex between trypsin-modified elongation factor Tu-MgGDP from Escherichia coli and the antibiotic tetracycline have been solved by X-ray diffraction analysis to resolutions of 2.8 and 2.1 A, respectively. In the P2(1) form, cocrystals were grown from a solution mixture of the protein and tetracycline. Six copies of the trypsin-modified EF-Tu-MgGDP-tetracycline complex are arranged as three sets of dimers in the asymmetric unit. In the second crystal form, tetracycline was diffused into P4(3)2(1)2 crystals, resulting in a monomeric complex in the asymmetric unit. Atomic coordinates have been refined to crystallographic R factors of 18.0% for the P2(1) form and 20.0% for the P4(3)2(1)2 form. In both complexes, tetracycline makes significant interactions with the GTPase active site of EF-Tu. The phenoldiketone moiety of tetracycline interacts directly with the Mg(2+), the alpha-phosphate group of GDP and two amino acids, Thr25 and Asp80, which are conserved in the GX(4)GKS/T and DX(2)G sequence motifs found in all GTPases and many ATPases. The molecular complementarity, previously unrecognized between invariant groups present in all GTPase/ATPases and the active moiety of tetracycline, may have wide-ranging implications for all drugs containing the phenoldiketone moiety as well as for the design of new compounds targeted against a broad range of GTPases or ATPases.
authors.affiliation: Department of Physiology and Biophysics, 346-D Med Sci I, University of California, Irvine, CA 92697-4560, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Heffron
authors.forename: Suet
authors.initials: S
authors.lastname: Mui
authors.forename: Annette
authors.initials: A
authors.lastname: Aorora
authors.forename: Kenton
authors.initials: K
authors.lastname: Abel
authors.forename: Ernst
authors.initials: E
authors.lastname: Bergmann
authors.forename: Frances
authors.initials: F
authors.lastname: Jurnak
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray / Q000379:methods; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000737:chemistry / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D013752:Tetracycline / Q000737:chemistry* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D006153:Guanosine Diphosphate; D010444:Peptide Elongation Factor Tu; D013752:Tetracycline