Fig. 3.

The cavity between the two subdomains of StHypT-RD. (A) A 2.0-Å resolution structure of StHypT-RD, which is drawn in ribbon representation. The dimer, colored in pink and gray, is generated by the crystallographic symmetry (Left). Three methionine residues are in ball-and-stick representation (green). The cavities between the two subdomains (RD-I and RD-II) are indicated by red arrows, which is detailed in B. (B) An enlarged intersection view of the cavity. The Met206 residue (green, ball-and-stick) is located in a solvent-accessible position and is surrounded by the residues shown in brown sticks. (C and D) Structural details of cavities are depicted with the omit maps around water molecules in apo-form (C) and an HOCl (or OCl⁻) molecule in HOCl-soaked StHypT-RD (D). The Fo-Fc omit maps were contoured at 3.0 σ (mesh). Dotted-lines indicate the interaction between protein and small molecules (water or HOCl). N, O, S, and Cl atoms are colored in blue, red, yellow, and green, respectively.