Open AccessA Small‐Angle X‐Ray Scattering Study of the Complex Formation between Elongation Factor. Tu · GTP and Valyl‐tRNA Val 1 from Escherichia coli
Author(s) -
ÖSTERBERG Ragnar,
SJÖBERG Bo,
LIGAARDEN Roar,
ELIAS Per
Publication year - 1981
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1981.tb06314.x
Subject(s) - ef tu , gtp' , transfer rna , elongation , crystallography , scattering , elongation factor , radius of gyration , radius , chemistry , physics , ribosome , rna , nuclear magnetic resonance , materials science , biochemistry , optics , enzyme , computer security , ultimate tensile strength , computer science , metallurgy , gene , polymer
The complex formation between elongation factor Tu (EF‐Tu) · GTP and valyl‐tRNA Val 1 has bin investigated using the small‐angle X‐ray scattering titration technique. The main species observed is a 1:1 complex with a stability constant log K ≥ 6. The corresponding interaction between EF‐Tu · GTP and non‐aminoacylated tRNA appears to be much weaker with an estimated log K∼4. The radius of gyration determined for the EF‐Tu · GTP—valyl‐tRNA Val 1 complex is larger (R = 3.6 nm) than that of EF‐Tu · GTP (R = 2.5 nm). Likewise, the maximum distance within this complex is larger (D max = 12.5 nm) than the one within EF‐Tu · GTP (D max = 8.5 nm). These data as well as the p ( r ) curve are consistent with a multiellipsoid model for the complex. From this model it is indicated that the acceptor stem of tRNA is attached to EF‐Tu and that the anticodon stem and loop protrude into the solution.