Comparison of a fungal (family I) and bacterial (family II) cellulose-binding domain

• Published in: Journal of Bacteriology Vol. 177; no. 15; pp. 4356 - 4363
• Main Authors: Tomme, P. (University of British Columbia, Vancouver, BC, Canada.), Driver, D.P, Amandoron, E.A, Miller, R.C. Jr, Antony, R, Warren, J, Kilburn, D.G
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01-08-1995
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN RECOMBINADO; ADN RECOMBINE; Amino Acid Sequence; BACTERIA; Bacteriology; Base Sequence; beta-Glucosidase - genetics; beta-Glucosidase - metabolism; Biochemistry; Carrier Proteins - biosynthesis; Carrier Proteins - genetics; Carrier Proteins - metabolism; CELLULOLYSE; CELLULOSE; Cellulose - genetics; Cellulose - metabolism; Cellulose 1,4-beta-Cellobiosidase; CELULOLISIS; CELULOSA; Cloning, Molecular; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; DNA, Bacterial - metabolism; DNA, Fungal - metabolism; ESCHERICHIA COLI; Escherichia coli - genetics; Escherichia coli - metabolism; EXPRESION GENICA; EXPRESSION DES GENES; Fungi; GENE; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Fungal; GENES; GENIE BIOCHIMIQUE; Glucan 1,3-beta-Glucosidase; Glycoside Hydrolases - biosynthesis; Glycoside Hydrolases - genetics; Glycoside Hydrolases - metabolism; Gram-Positive Asporogenous Rods - genetics; HIDROLASAS; HYDROLASE; INGENIERIA BIOQUIMICA; Molecular Sequence Data; Plasmids - genetics; Recombinant Fusion Proteins; TRANSFORMACION GENETICA; TRANSFORMATION GENETIQUE; Trichoderma - genetics; TRICHODERMA LONGIBRACHIATUM; XILANOS; Xylan Endo-1,3-beta-Xylosidase; XYLANE; Xylosidases - genetics; Xylosidases - metabolism
• ISSN: 0021-9193; 1098-5530; 1067-8832
• DOI: 10.1128/jb.177.15.4356-4363.1995

A family II cellulose-binding domain (CBD) of an exoglucanase/xylanase (Cex) from the bacterium Cellulomonas fimi was replaced with the family I CBD of cellobiohydrolase I (CbhI) from the fungus Trichoderma reesei. Expression of the hybrid gene in Escherichia coli yielded up to 50 mg of the hybrid protein, CexCBDCbhI, per liter of culture supernatant. The hybrid was purified to homogeneity by affinity chromatography on cellulose. The relative association constants (Kr) for the binding of Cex, CexCBDCbhI, the catalytic domain of Cex (p33), and CbhI to bacterial microcrystalline cellulose (BMCC) were 14.9, 7.8, 0.8, and 10.6 liters g-1, respectively. Cex and CexCBDCbhI had similar substrate specificities and similar activities on crystalline and amorphous cellulose. Both released predominantly cellobiose and cellotriose from amorphous cellulose. CexCBDCbhI was two to three times less active than Cex on BMCC, but significantly more active than Cex on soluble cellulose and on xylan. Unlike Cex, the hybrid protein neither bound to alpha-chitin nor released small particles from dewaxed cotton fibers