Resistance of archaebacterial aEF-1 alpha.GDP against denaturation by heat and urea.
The elongation factor aEF-1 alpha, isolated as aEF-1 alpha.GDP from the thermoacidophilic archaebacterium Sulfolobus solfataricus, exchanges GDP for [3H]GDP at a rate which reaches a maximum at 95 degrees C. The rate constants at different temperatures of the heat inactivation of aEF-1 alpha.GDP are considerably lower compared to those referred to Escherichia coli EF-Tu.GDP. The Tm values determined for both aEF-1 alpha.GDP and EF-Tu.GDP are 97 and 53 degrees C, respectively. The addition of GDP during the heat treatment protects significantly EF-Tu.GDP but only slightly aEF-1 alpha.GDP. The ability of aEF-1 alpha.GDP to exchange GDP for [3H]GDP is impaired at 70 degrees C by urea at concentrations which are greater compared to those required to inactivate E. coli EF-Tu.GDP at 45 degrees C; apparently both factors are not protected by GDP against inactivation by urea.
Masullo
M
M
Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Italy.
Raimo
G
G
Bocchini
V
V
D004926:Escherichia coli; D006153:Guanosine Diphosphate / Q000737:chemistry / Q000302:isolation & purification*; D006358:Hot Temperature; D007700:Kinetics; D020648:Peptide Elongation Factor 1; D010444:Peptide Elongation Factor Tu / Q000737:chemistry; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000302:isolation & purification*; D011489:Protein Denaturation; D016944:Sulfolobus / Q000235:genetics*; D014316:Tritium; D014508:Urea
D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D014316:Tritium; D006153:Guanosine Diphosphate; D014508:Urea; D010444:Peptide Elongation Factor Tu