title: Engineering a family 9 processive endoglucanase from Paenibacillus barcinonensis displaying a novel architecture.
abstract: Cel9B from Paenibacillus barcinonensis is a modular endoglucanase with a novel molecular architecture among family 9 enzymes that comprises a catalytic domain (GH9), a family 3c cellulose-binding domain (CBM3c), a fibronectin III-like domain repeat (Fn3(1,2)), and a C-terminal family 3b cellulose-binding domain (CBM3b). A series of truncated derivatives of endoglucanase Cel9B have been constructed and characterized. Deletion of CBM3c produced a notable reduction in hydrolytic activity, while it did not affect the cellulose-binding properties as CBM3c did not show the ability to bind to cellulose. On the contrary, CBM3b exhibited binding to cellulose. The truncated forms devoid of CBM3b lost cellulose-binding ability and showed a reduced activity on crystalline cellulose, although activity on amorphous celluloses was not affected. Endoglucanase Cel9B produced only a small ratio of insoluble products from filter paper, while most of the reducing ends produced by the enzyme were released as soluble sugars (91%), indicating that it is a processive enzyme. Processivity of Cel9B resides in traits contained in the tandem of domains GH9-CBM3c, although the slightly reduced processivity of truncated form GH9-CBM3c suggests a minor contribution of domains Fn3(1,2) or CBM3b, not contained in it, on processivity of endoglucanase Cel9B.
authors: Department of Microbiology, Faculty of Biology, University of Barcelona, Av. Diagonal 645, Barcelona, Spain.
authors: Alina Iulia
authors: AI
authors: Chiriac
authors: Edith Marleny
authors: EM
authors: Cadena
authors: Teresa
authors: T
authors: Vidal
authors: Antonio L
authors: AL
authors: Torres
authors: Pilar
authors: P
authors: Diaz
authors: F I Javier
authors: FI
authors: Pastor
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002480:Cellulase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D008969:Molecular Sequence Data; D056507:Paenibacillus / Q000201:enzymology* / Q000235:genetics*; D011485:Protein Binding; D015202:Protein Engineering; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017384:Sequence Deletion
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D002482:Cellulose; D002480:Cellulase