A threedimensional protein molecular structure

which was encoded by the gene Ribose5phosphate isomerase A (RpiA) from Acidithiobacillus ferrooxidans，was constructed by the homologymodeling technique and moleculardynamics simulation. The obtained structure was applied to search binding sites and carry out flexible docking with the substrate ribose5phosphate (R5P). The results showed that the substrate R5P can be effectively recruited into the active pocket and be activated immediately; the residues of Asp81

Thr31

Lys121

Ser30

Glu103

Asp84

Lys94

Asp118

Lys7

Gly97

Gly29

Gly95

Thr28 and H2O play a critical role in the binding or catalysis of R5P. Among the above residues

Gly97

Gly29

Gly95

Thr28 are fitly conserved in RpiA from all kinds of sources but have not been detected before.