title: [Properties and role of tryptophan residues in the polypeptide chain of elongation factor G from E. coli].
abstract: Using chemical modification and spectrofluorimetry, it was shown that two tryptophane residues of the elongation factor G (EF-G) in positions 51 and 71 from the N-terminus are located on the surface of the EF-G molecule. The tryptophane residue in position 71 is effectively shielded against modification at binding of EF-G guanyl nucleotides. Modification of these tryptophane residues does not result in a loss of the nucleotide-binding activity but completely inhibits EF-G binding to the ribosome. Polarized fluorescence study showed that the relaxation properties of these exposed tryptophane residues essentially depend both on the presence of the C-terminal domain and on binding of nucleotides in the nucleotide-binding site located in the N-terminal part of EF-G. It was assumed that the C-terminal domain, the nucleotide-binding site and the site responsible for the EF-G binding to the ribosome are brought together in the three-dimensional structure of the elongation factor G.
mesh_terms: D004926:Escherichia coli / Q000378:metabolism*; D007700:Kinetics; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors / Q000378:metabolism*; D011487:Protein Conformation; D012270:Ribosomes / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014364:Tryptophan
chemical_list: D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D014364:Tryptophan
vernacular_title: Svoĭstva i rol' ostatkov triptofana polipeptidnoĭ tsepi faktora élongatsii G E. coli.