Microcalorimetric study of elongation factor Tu from Thermus thermophilus in nucleotide-free, GDP and GTP forms and in the presence of elongation factor Ts.
Elongation factor (EF) Tu undergoes profound nucleotide-dependent conformational changes in its functional cycle. The thermodynamic parameters of the different Thermus thermophilus EF-Tu forms, its domains I, II/III and III, were determined by microcalorimetry. Thermal transitions of the EF-Tu.GDP and EF-Tu.guanosine-5'-[beta,gamma-imido]triphosphate have a cooperative two-state character. Nucleotide removal affected the cooperativity of the thermal transition of EF-Tu. Microcalorimetric measurements of nucleotide-free EF-Tu and its separated domains showed that domains II/III have the main stabilizing role for the whole protein. Despite the fact that strong interactions between elongation factors Tu and Ts from T. thermophilus at 20 degrees C exist, the thermal transition of neither protein in the complex was significantly affected.
Sedlák
Erik
E
Department of Biochemistry, Faculty of Science P.J. Safárik University, Kosice, Slovakia. sedlak_er@saske.sk
Sprinzl
Mathias
M
Grillenbeck
Norbert
N
Antalík
Marián
M
D002152:Calorimetry, Differential Scanning; D006153:Guanosine Diphosphate / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000737:chemistry; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D010445:Peptide Elongation Factors / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D016963:Thermus thermophilus / Q000378:metabolism*
D010445:Peptide Elongation Factors; C023512:elongation factor Ts; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu