Modulation of a salt link does not affect binding of phosphate to its specific active transport receptor

The modulation of ionic interactions has no effect on the binding of phosphate to its active transport receptor in a phosphate binding protein from Escherichia coli. Local induced dipoles and hydrogen bonds stabilize the charge on the phosphate and compensate for the damage done by modulation of ionic interactions. The mutations in Arg 135 and Asp 137 in the protein using site directed mutagenesis induce modulations of ionic interactions.