Amino acid sequence alignment of EstE1 and its homologous HSL-family hyperthermophilic and mesophilic esterases. Amino acid sequence of EstE1 was aligned with those of the hyperthermophilic carboxyesterase AFEST (Protein Data Bank [PDB] code 1JJI) from archaeon Archaeoglobus fulgidus and the mesophilic brefeldin A esterase (BFAE) from Bacillus subtilis (PDB code 1JKM). The regions encompassing EstE1 dimerization motifs and the sequence blocks showing the amino acids involved in the formations of the catalytic triad and oxyanion hole are presented. Identical and similar residues have a grey background. Symbols: ●, amino acids forming a catalytic triad; ○, amino acids involved in oxynion hole formation; □ and ▯, amino acid residues involved in hydrophobic and ionic interactions at 1JJI dimeric interface, respectively; ▯, amino acid residues involved in ionic interactions at 1JKM dimeric interface; ■ and ▲ amino acid residues involved in hydrophobic and ionic interactions at EstE1 dimeric interface, respectively. Amino acid sequence alignment was performed as described previously .