The peptide binding site of the heat-treatment complex of 1510-N K138A–234P10 (in a stereoview). One monomer (chain A) of 1510-N K138A is colored grey, and the other monomer (chain B) of 1510-N K138A is colored green. The peptide is shown as a yellow stick. The catalytic Ser97 and Ala138 (replaced Lys) residues are shown as magenta sticks. The tips of L2 loops (residues 126–133) are colored red. The view is almost the same as in Fig. 2.