title: Renaturation of rhodanese by translational elongation factor (EF) Tu. Protein refolding by EF-Tu flexing.
abstract: The translation elongation factor (EF) Tu has chaperone-like capacity to promote renaturation of denatured rhodanese. This renaturation activity is greatly increased under conditions in which the factor can oscillate between the open and closed conformations that are induced by GDP and GTP, respectively. Oscillation occurs during GTP hydrolysis and subsequent replacement of GDP by EF-Ts which is then displaced by GTP. Renaturation of rhodanese and GTP hydrolysis by EF-Tu are greatly enhanced by the guanine nucleotide exchange factor EF-Ts. However, renaturation is reduced under conditions that stabilize EF-Tu in either the open or closed conformation. Both GDP and the nonhydrolyzable analog of GTP, GMP-PCP, inhibit renaturation. Kirromycin and pulvomycin, antibiotics that specifically bind to EF-Tu and inhibit its activity in peptide elongation, also strongly inhibit EF-Tu-mediated renaturation of denatured rhodanese to levels near those observed for spontaneous, unassisted refolding. Kirromycin locks EF-Tu in the open conformation in the presence of either GTP or GDP, whereas pulvomycin locks the factor in the closed conformation. The results lead to the conclusion that flexing of EF-Tu, especially as occurs between its open and closed conformations, is a major factor in its chaperone-like refolding activity.
authors.affiliation: Molecular Biology Institute and the Department of Chemistry & Biochemistry, The University of Texas, Austin, Texas 78712, USA.
authors.forename: W
authors.initials: W
authors.lastname: Kudlicki
authors.forename: A
authors.initials: A
authors.lastname: Coffman
authors.forename: G
authors.initials: G
authors.lastname: Kramer
authors.forename: B
authors.initials: B
authors.lastname: Hardesty
mesh_terms: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000378:metabolism; D004793:Enzyme Reactivators / Q000378:metabolism; D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000378:metabolism; D007700:Kinetics; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D011728:Pyridones / Q000378:metabolism; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004793:Enzyme Reactivators; D011728:Pyridones; C012521:pulvomycin; D013884:Thiosulfate Sulfurtransferase; D020963:GTP Phosphohydrolase-Linked Elongation Factors; D010444:Peptide Elongation Factor Tu; C008536:mocimycin