Christina Divne

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Cellulose is the major polysaccharide of plants where it plays a predominantly structural role. A variety of highly specialized microorganisms have evolved to produce enzymes that either synergistically or in complexes can carry out the complete hydrolysis of cellulose. The structure of the major cellobiohydrolase, CBHI, of the potent cellulolytic fungus(More)
Cellobiose dehydrogenase, the only currently known extracellular flavocytochrome, is formed not only by a number of wood-degrading but also by various phytopathogenic fungi. This inducible enzyme participates in early events of lignocellulose degradation, as investigated in several basidiomycete fungi at the transcriptional and translational level. However,(More)
Beta-galactosidase from the probiotic strain Lactobacillus acidophilus R22 was purified to apparent homogeneity by ammonium sulphate fractionation, hydrophobic interaction, and affinity chromatography. The enzyme is a heterodimer consisting of two subunits of 35 and 72 kDa, as determined by gel electrophoresis. The optimum temperature of beta-galactosidase(More)
Cellulose is the most abundant polymer in the biosphere. Although generally resistant to degradation, it may be hydrolysed by cellulolytic organisms that have evolved a variety of structurally distinct enzymes, cellobiohydrolases and endoglucanases, for this purpose. Endoglucanase I (EG I) is the major endoglucanase produced by the cellulolytic fungus(More)
The roles of the residues in the catalytic trio Glu212-Asp214-Glu217 in cellobiohydrolase I (CBHI) from Trichoderma reesei have been investigated by changing these residues to their isosteric amide counterparts. Three mutants, E212Q, D214N and E217Q, were constructed and expressed in T. reesei. All three point mutations significantly impair the catalytic(More)
Detailed information has been obtained, by means of protein X-ray crystallography, on how a cellulose chain is bound in the cellulose-binding tunnel of cellobiohydrolase I (CBHI), the major cellulase in the hydrolysis of native, crystalline cellulose by the fungus Trichoderma reesei. Three high-resolution crystal structures of different catalytically(More)
The hemoflavoenzyme cellobiose dehydrogenase (CDH) from the white-rot fungus Phanerochaete chrysosporium has been heterologously expressed in the methylotrophic yeast Pichia pastoris. After 4 days of cultivation in the induction medium, the expression level reached 1800 U/L (79 mg/L) of CDH activity, which is considerably higher than that obtained(More)
BACKGROUND The fungal oxidoreductase cellobiose dehydrogenase (CDH) degrades both lignin and cellulose, and is the only known extracellular flavocytochrome. This haemoflavoenzyme has a multidomain organisation with a b-type cytochrome domain linked to a large flavodehydrogenase domain. The two domains can be separated proteolytically to yield a functional(More)
The exo-loop of Trichoderma reesei cellobiohydrolase Cel7A forms the roof of the active site tunnel at the catalytic centre. Mutants were designed to study the role of this loop in crystalline cellulose degradation. A hydrogen bond to substrate made by a tyrosine at the tip of the loop was removed by the Y247F mutation. The mobility of the loop was reduced(More)
Cellobiose dehydrogenases (CDHs) are extracellular hemoflavoenzymes that are thought to be involved in the degradation of two of the most abundant biopolymers in the biosphere, cellulose and lignin. To date, these enzymes, consisting of a cytochrome domain and a flavin domain, have been detected and sequenced exclusively in the kingdom of fungi. Independent(More)