FIGURE 1.

The PAM linker region includes a conserved His cluster. A, the major splice variants of PAM, PAM-1 and PAM-2, are shown; the linker region separating the catalytic cores of PAM-1 (PHMcc and PALcc) is composed of 12 amino acids encoded by the final exon of PHMcc (light blue; rat exon 13), 24 amino acids of rat exon 15 (purple), and 105 amino acids of exon 16 (orange). The linker region in PAM-2 lacks the region encoded by exon 16. B, the CLUSTALW sequence alignment for the linker region is shown, with the conserved His cluster indicated; accession numbers are provided. C, Coomassie Brilliant Blue R-250 staining shows purified recombinant WT linker and H3A linker.