Akademik Veri Yönetim Sistemi
European Journal of Biochemistry, cilt.103, sa.3, ss.551-555, 1980 (Scopus)
Interactions of rat liver elongation factor 2 (EF‐2) with guanine nucleotides and ribosomes were studied by equilibrium dialysis and sedimentation methods. GDP (Kd= 0.5 μM) or GDP‐Mg2+ (Kd=1.57 μM) displayed a higher affinity in the formation of a binary complex with EF‐2 than GTP (Kd= 2.68 μM), GTP‐Mg2+ (Kd= 2.77 μM), or guanosine 5′‐[β,γ‐methylene]triphosphate (GuoPP[CH2]P) (Kd= 24.0 μM). NaIO4‐oxidized guanine nucleotides (oGDP) (Kd= 38 μM) and oxidized/reduced guanine nucleotides (orGDP) (Kd= 27 μM) had lower affinites to the binding site on EF‐2 than those of GDP or GTP. However, the binding of oGDP, oGTP or oGuoPP[CH2]P to EF‐2 resulted in the formation of a stable product which could be recovered by the nitrocellulose filter technique or by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. In the presence of ribosomes and EF‐2 the formation of a new binding site (or a different conformation of the binding site) with a higher affinity for GuoPP[CH2]P‐Mg2+ (Kd= 0.26 μM) than for GDP‐Mg2+ (Kd= 9.3 μM) became apparent. The presence of ribosomes thus appeared to favor the formation of a complex involving guanosine triphosphates. Adenosine diphosphate ribosylated EF‐2 (ADP‐Rib‐EF‐2) in its turn could bind to the ribosome with high affinity even without guanosine nucleotides (Kd= 0.18 μM). GuoPP[CH2]P increased to some extent the affinity of ADP‐Rib‐EF‐2 for its ribosomal binding site (Kd= 0.05 μM). Copyright © 1980, Wiley Blackwell. All rights reserved