Immobilization metal affinity chromatography(IMAC)and size-exclusive chromatography(SEC)have been widely used in the purification of recombinant protein.In order to apply the column chromatography to the separation and purification of the gene recombinant with histidine-tags,the column chromatographic separation characteristics of N-terminal histidine-tagged(N-AxCeSD)and C-terminal histidine-tagged(C-AxCeSD)gene recombinant protein AxCeSD,one of the subunit involved in the cellulose synthesis in Acetobacter xylinum were studied.In the ring-shaped three-dimensional structure of AxCeSD,N-terminal histidine-tags were located in the inner of ring,while C-terminal histidine-tags were located in the outer.A higher imidazole concentration was necessary for eluting the C-AxCeSD from the IMAC column due to the C-terminal histidine-tags had stronger chelating interaction with the Ni2+ on the IMAC media.Moreover,the retention time for eluting C-AxCeSD from the same SEC gel column was shorter than that for N-AxCeSD,because the larger protein homolog was formed in the C-AxCeSD solution through the inter-molecular hydrogen bonds between the C-terminal histidine-tags.
