title: Direct observation of poly(3-hydroxybutyrate) depolymerase adsorbed on polyester thin film by atomic force microscopy.
abstract: Poly[(R)-3-hydroxybutyrate] (PHB) depolymerases adsorbed on poly(L-lactide) (PLLA) thin film were directly observed by atomic force microscopy (AFM). A PLLA thin film of 100 nm thickness was prepared on a silicon wafer by spin-cast method. The PLLA thin film was treated at 220 degrees C and quenched to room temperature, resulting in the formation of a completely amorphous film with a smooth surface. Then, the PHB depolymerases from Pseudomonas stutzeri YM1006 and Ralstonia pickettii T1 were dispersed on the amorphous PLLA thin film. Direct AFM observation has revealed that the PHB depolymerases bind in an elliptic shape on the surface of the PLLA thin film and that a small ridge is created around each enzyme molecule. After removal of the enzymes with 40% ethanol aqueous solution, small hollows were found on the PLLA thin film. These results suggest that a PHB depolymerase interacts with polyester molecules during their adsorption to make a hollow on the substrate surface.
authors.affiliation: Polymer Chemistry Laboratory, RIKEN Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan. ykikkawa@riken.jp
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kikkawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fujita
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hiraishi
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yoshimoto
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Doi
mesh_terms: D000327:Adsorption; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000378:metabolism*; D018625:Microscopy, Atomic Force / Q000379:methods*; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*
chemical_list: D011091:Polyesters; D002265:Carboxylic Ester Hydrolases; C022417:poly-beta-hydroxybutyrate depolymerase