Fig. 4: Critical residues in the GDP-binding pocket.

a A ribbon representation of the EF-Tu•GDP structure, which is colored as Fig. 1a. GDP and Mg²⁺ were located in Domain I. GDP is shown as sticks, and Mg²⁺ is shown as a green sphere. b Representation of GDP-binding sites in the EF-Tu•GDP complex. The broken black lines represented the hydrogen bonds formed between EF-Tu and GDP. The related residues were labeled and shown as sticks. c The electrostatic potential surface of the EF-Tu•GDP complex. Red indicated the negative potential, and blue indicated the positive potential. GDP is shown as sticks, and Mg²⁺ is shown as a green sphere. d Superimposition of Mtb EF-Tu between the EF-Tu•GDP (yellow) and EF-Tu•EF-Ts (marine) complexes. The RMSD value for the Cα alignment between the two structures was 0.711 Å. e The detailed shift of GDP-bound residues between the EF-Tu•GDP and EF-Tu•EF-Ts complexes. The broken black lines represented the shifting of labeled residues.