Critical role of the N-terminal region in the catalytic activity of DUSP26-N.

<p>(A) Superposition of the DUSP26-C monomer (red) onto the DUSP26-N (C152S) monomer (green). The black dotted circle highlights the large conformational difference in the α7-α8 loop between DUSP26-N (C152S) and DUSP26-C. The additional N-terminal region (residues 39–60) of DUSP26-N (C152S) is colored blue. (B) Hydrogen bonding interaction network among the PTP-loop, its surrounding α7-α8 loop, and α1-helix in DUSP26-N (C152S). Residues in the PTP-loop (Gly155, Val156, and Ser157) and the N-terminal domain (Arg50, Tyr53, and Lys56) form hydrogen bonds with residues in the α7-α8 loop. The residues in the N-terminal domain, α7-α8 loop, and PTP-loop are shown as light blue, green, and dark blue, respectively. Hydrogen bonds are indicated by dotted lines.