title: Archaeal elongation factor 1 beta is a dimer. Primary structure, molecular and biochemical properties.
abstract: The elongation factor 1 beta (EF-1 beta), that in eukarya and archaea promotes the replacement of GDP by GTP on the elongation factor 1 alpha x GDP complex, was purified to homogeneity from the thermoacidophilic archaeon Sulfolobus solfataricus (SsEF-1 beta). Its primary structure was established by sequenced Edman degradation of the entire protein or its proteolytic peptides. The molecular weight of SsEF-1 beta was estimated as about 10000 or 20000 under denaturing or native conditions respectively; this finding suggests that the native protein exists as a dimer. The peptide chain of SsEF-1 beta is much shorter than that of its eukaryotic analogues and homology is found only at their C-terminal region; no homology exists between SsEF-1 beta and eubacterial EF-Ts. At 50 degrees C, at a concentration of SsEF-1 beta 5-fold higher than that of SsEF-1 alpha x [3H]GDP the rate of the exchange of [3H]GDP for GTP becomes about 160-fold faster. An analysis of the values of the energetic parameters indicates that in the presence of SsEF-1 beta the GDP/GTP exchange is entropically favoured. At 100 degrees C the half-life of SsEF-1 beta is about 4 h.
authors.affiliation: Dipartimento di Biochimica e Biotecnologie Mediche, Università di Napoli Federico II, Napoli, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Raimo
authors.forename: M
authors.initials: M
authors.lastname: Masullo
authors.forename: G
authors.initials: G
authors.lastname: Savino
authors.forename: G
authors.initials: G
authors.lastname: Scarano
authors.forename: G
authors.initials: G
authors.lastname: Ianniciello
authors.forename: A
authors.initials: A
authors.lastname: Parente
authors.forename: V
authors.initials: V
authors.lastname: Bocchini
mesh_terms: D001704:Biopolymers; D010450:Endopeptidases / Q000378:metabolism; D019143:Evolution, Molecular; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D011487:Protein Conformation; D011489:Protein Denaturation; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016944:Sulfolobus / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D001704:Biopolymers; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors; D012261:Ribonucleoproteins; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D010450:Endopeptidases