Elongation factor 1 from the silk gland of silkworm Purification and some properties of its γ subunit having EF‐1b activity

Moonlighting Functions of Polypeptide Elongation Factor 1: From Actin Bundling to Zinc Finger Protein R1-Associated Nuclear Localization

“…1). 10) Finally, as summarized in Table 1, EF-1 was shown to consist of four diŠerent subunits, EF-1abb?g in plants, 11) and EF1abgd (or EF-1a2bgd) in animals. 12) Yeast EF-1 consists of three subunits, EF-1abg.…”

“…10) Although the physiological signiˆcance is unknown, there are many reports suggesting that EF-1g may have some cellular regulatory functions: EF-1g has the ability to bind to microtubules, 37) EF-1g mRNA is over-expressed in carcinomas (Section 6), and the consensus amino acid residues that are necessary for the glutathione S-transferase (GST) activity are conserved in EF-1g from various eukaryotes.…”

Elongation factor 1 from the silk gland of silkworm

“…An inhibitor of EF-G-and ribosome-dependent uncoupled GTPase activity was isolated from Escherichia coli [lo] ; however, EF-1 b (EF-1 bc) had no effect on the EF-2-and ribosome-dependent GTPase activity. These results indicate that EF-lb (EF-lbc) is a significant factor that not only catalyzes the exchange of GDP bound to EF-la with exogeneous GTP [4] , but also regulates the hydrolysis of GTP in the aa-tRNA binding reaction. Although EF-la forms a ternary complex with aa-tRNA and GTP, and the GTP in the complex is hydrolyzed in the presence of ribosomes, free EF-la also hydrolyzes GTP directly in the presence of ribosomes as described above.…”

“…EF-1 c (p subunit) and EF-lb (7 subunit) was purified from EF-1, by ion exchange chromatography in the presence of 6 M urea as in [4] . EF-lbc (complex of y and /3 subunits) was purified from EF-1, according to the method in [7] with slight modifications.…”

“…wt z 1.5 X 10') consisting of three different subunits (o,P and 7) ['VI were resolved into complementary factors EF-la (o subunit, APase I) and EF-lb (y subunit, APase II) [3,4] . They correspond to EF-Tu and EF-Ts, respectively [4] , Although for prokaryotes [S] and for eukaryotes [6] the stoichiometry of the amount of aa-tRNA bound to ribosome and the amount of GTP cleaved in the binding reaction was shown, no data were obtained about the aa_tRNA-dependent GTPase of EF-1 which was resolved into complementary factors (EF-la and EF-lb). We describe here EF-la-and ribosome-dependent GTPase (nonspecific GTPase) which is observed in the absence of aa-tRNA.…”