Open AccessElongation Factor T from Bacillus stearothermophilus and Escherichia coli
Author(s) -
WITTINGHOFER Alfred,
LEBERMAN Reuben
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10169.x
Subject(s) - ef tu , escherichia coli , nucleotide , chemistry , elongation , elongation factor , reagent , bacillus (shape) , homogeneous , gel electrophoresis , polyacrylamide gel electrophoresis , electrophoresis , biochemistry , crystallography , chromatography , stereochemistry , biology , enzyme , organic chemistry , microbiology and biotechnology , materials science , thermodynamics , ribosome , transfer rna , rna , physics , ultimate tensile strength , metallurgy , gene
Homogeneous preparations of elongation factors EF‐Tu and EF‐Ts from Bacillus stearothermophilus have been obtained with specific activities of 20000 ± 2000 and 5 ± 50 000 units/ mg, respectively. By dodecylsulphate‐polyacrylamide gel electrophoresis the molecular weight of EF‐Tu was found to be 49000 ± 2000 and of EF‐Ts 35500 ± 1000. Nucleotide‐free EF‐Tu was prepared by using ITP as a GDP‐binding‐site‐directed analogue. EF‐Tu was shown to contain two sulphydryl groups, one reacting fast and one slowly with N ‐ethylmaleimide and 5,5′‐dithio‐bis(2nitrobenzoic acid) under non‐denaturing conditions. The same reagents were shown to react with the three sulphydryl groups of EF‐Ts in the native state. The heat stabilities of EF‐Tu and EF‐Ts are reversed with respect to the Escherichia coli factors, EF‐Tu being the more stable protein; even nucleotide‐free EF‐Tu is relatively stable with a half‐life at room temperature of about 35 h.