FIG. 1.
Structure-based sequence alignment of CE4 esterases. The sequences of three known de-N-acetylases, a de-O-acetylase, and PgdASm from the CE4 family are shown: S. mutans PgdA, C. lindemuthianum chitin de-N-acetylase, B. subtilis PdaA, Streptomyces lividans xylan de-O-acetylase, and S. pneumoniae PgdA. The secondary structures of PgdASm and PgdASp are indicated above and below the alignment, respectively. The secondary structure is highlighted as red helices, and blue strands represent the CE4 esterase domain. Secondary structure not present in the canonical CE4 fold is shown in green. The five CE4 active-site motifs (MT1 to MT5, yellow) are indicated below the alignment. The metal coordinating residues are colored cyan, and the catalytic residues are colored magenta. Residues highlighted in orange show large shifts in surface-exposed loops. The alignment was performed using the Aline program (written and kindly provided by Charlie Bond, University of Western Australia, and Alexander Schüttelkopf, Dundee University).