Substitution of aspartic acid-80, a residue involved in coordination of magnesium, weakens the GTP binding and strongly enhances the GTPase of the G domain of elongation factor Tu

The functional role of Asp80, a residue involved in the coordination of the Mg 2+ .guanine nucleotide complex in elongation factor Tu (EF-Tu), has been investigated by its substitution with Asn in the isolated N-terminal domain (G domain). The G domain D80N is characterized by a strong decrease in binding affinity for GTP and magnesium, whereas the affinity for GDP is unchanged. This effect can be mimicked in wild-type G domain by the addition of EDTA