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 1.76Å. The overall structure of Est119 displays a typical α/β-hydrolase fold consisting of a central twisted β-sheet of nine β-strands that are flanked by nine α-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.