An intact conformation at the tip of elongation factor G domain IV is functionally important
K A Martemyanov1, A S Yarunin, A Liljas
1Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region.
Abstract:
Three variants of Thermus thermophilus EF-G with mutations in the loop at the distal end of its domain IV were obtained. The replacement of His-573 by Ala and double mutation H573A/D576A did not influence the functional activity of EF-G. On the other hand, the insertion of six amino acids into the loop between residues Asp-576 and Ser-577 reduced the translocational activity of EF-G markedly, while its GTPase activity was not affected. It is concluded that the native conformation of the loop is important for the factor-promoted translocation in the ribosome. The functional importance of the entire EF-G domain IV is discussed.
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