title: An intact conformation at the tip of elongation factor G domain IV is functionally important.
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.
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region.
authors.forename: K A
authors.initials: KA
authors.lastname: Martemyanov
authors.forename: A S
authors.initials: AS
authors.lastname: Yarunin
authors.forename: A
authors.initials: A
authors.lastname: Liljas
authors.forename: A T
authors.initials: AT
authors.lastname: Gudkov
mesh_terms: D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000378:metabolism; D009154:Mutation; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D016963:Thermus thermophilus / Q000235:genetics / Q000378:metabolism*
chemical_list: D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D020963:GTP Phosphohydrolase-Linked Elongation Factors