Functional EF-Tu with large C-terminal extensions in an E-coli strain with a precise deletion of both chromosomal tuf genes

An Escherichia coli strain was constructed in which both chromosomal genes encoding elongation factor (EF)-Tu (tufA and tufB) have been inactivated with precise coding sequence replacements. A tufA gene in an expression vector is supplied as the sole EF-Tu source. By using plasmid replacement, based on plasmid incompatibility, mutant EF-Tu variants with a large U-terminal extension up to 270 amino acids were studied and proved to be functional in a strain lacking the chromosomal tufA and tufB genes. (C) 2003 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.