Figure 5
(A) The MtbGmhA + D-sedoheptulose 7-phosphate (S7P) + Zn2+ complex model showing the α-helices (in cyan), β-sheets (in magenta), loops (in orange). The D-sedoheptulose 7-phosphate and Zn2+ ion are shown in red colors. (B) Electrostatic surface diagram of MtbGmhA monomer showing the D-sedoheptulose 7-phosphate and Zn2+ ion in the active site (blue positive surface). (C) LigPlot analysis of MtbGmhA + D-sedoheptulose 7-phosphate + Zn2+ complex showing the hydrogen bonds and van der Waals interactions between D-sedoheptulose 7-phosphate and Zn2+ with active site residues of MtbGmhA enzyme. The green dashed lines showed the hydrogen bonds and residues in “arc with spikes” are involved in van der waals interactions with ligands. (D) MtbGmhA + D-sedoheptulose 7-phosphate + Zn2+ tetramer showing each monomer in different color and D-sedoheptulose 7-phosphate and Zn2+ ligands in the active site of each monomer. (E) Electrostatic surface diagram of MtbGmhA tetramer showing four catalytic clefts (blue, positive charge), which accommodate the D-sedoheptulose 7-phosphate and Zn2+ in their binding pockets. (F) Interface between two MtbGmhA monomers, in which Glu66 residue (cyan) from one monomer and Zn2+ and Gln173 residue from another monomer binds to O1-C1 and O2-C2 of D-sedoheptulose 7-phosphate respectively and proposed as involved in isomerization of D-sedoheptulose 7-phosphate to D-glycero-D-α-manno-heptose-7-phosphate.
