Figure 3. Protein family classification of 80 carboxylesterases identified by activity screening of metagenomic libraries.

For all genes, the presence of esterase activity was confirmed by individual subcloning and expression in E. coli. Enzymes were classified into protein families using HMMER and BLAST searches of Pfam and COG databases. Polypeptide chain lengths are proportional to size and predicted domains are depicted as boxes. Domains predicted/confirmed to confer esterase activity are shown in yellow. Proteins selected for biochemical characterization in this work are shown in red font.