Figure 1.

(A) Ribbon-drawing of the crystal structure of the noncleaved YscU_N263A mutant and (B) the electrostatic potential mapped onto the solvent exposed surface of YscU_N263A in the same orientation. (C) Ribbon drawing of the crystal structure of the cleaved form of YscU (YscU_cleaved) and (D) the electrostatic potential mapped onto the surface of YscU_cleaved. (E) The molecular interactions of the NPTH residues located on the β-turn between strands β1 and β2 in the YscU_N263A structure and (F) after cleavage in the YscU_cleaved structure with carbon (gray), nitrogen (blue), and oxygen (red) atoms shown in stick form. The 2F_o-F_c electron density maps are shown contoured at 1.5 σ level. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]: