FIGURE 4.

The surface representation of BphB_B-356 in (A) apo form, (B) binary form, and (C) ternary structures in the presence of 23-DB and the (D) intermediate state. Residues Asp¹⁹⁰ and Arg⁴¹ are highlighted; in apo and binary structures they appear as separate residues, whereas in the ternary structure they appear to be joined due to the interaction between them. The circled region is part of substrate binding loop between Gly¹⁹⁸ and Val²¹⁶, which is not visible in apo and binary forms but is visible in the ternary and intermediate structures. Shift in the substrate binding loop in the ternary and intermediate regions could be seen. The spheres surrounding the coenzyme binding site and the active site show water molecules.