Crystal structure of cutinase Est119 from Thermobifida alba AHK119 that can degrade modified polyethylene terephthalate at 1.76 Å resolution

We determined the crystal structure of a cutinase from Thermobifida alba AHK119 (Est119) at a resolution of 1.76 angstrom. The overall structure of Est119 displays a typical alpha/beta-hydrolase fold consisting of a central twisted beta-sheet of nine beta-strands that are flanked by nine alpha-helices on both sides. The refined model contains two monomers in the asymmetric unit that form a dimer interface; a polyethylene glycol fragment is bound in the interface. Polyethylene glycol-binding site on the protein may suggest a glycol-binding site. A putative polymer-recognizing groove is observed to continue through the catalytic pocket. Water molecules are bound to hydrophilic amino acids along the groove, indicating the alternating pattern of polar and hydrophobic residues. (C) 2012 Elsevier Ltd. All rights reserved.