Multicomplex cellulase-xylanase system of Clostridium papyrosolvens C7

Abstract

The cellulase system of Clostridium papyrosolvens C7 was fractionated by means of ion-exchange chromatography into at least seven high-molecular-weight multiprotein complexes, each with different enzymatic and structural properties. The molecular weights of the complexes, as determined by gel filtration chromatography, ranged from 500,000 to 660,000, and the isoelectric points ranged from 4.40 to 4.85. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the complexes showed that each complex had a distinct polypeptide composition. Avicelase, carboxymethyl cellulase, and xylanase activity profiles difered from protein complex to protein complex. Three of the complexes hydrolyzed crystalline cellulose (Avicel). Activity zymograms of gels (following electrophoresis under mildly denaturing conditions) revealed different carboxymethyl cellulaseactive proteins in all complexes but xylanase-active proteins in only two of the complexes. The xylanase specific activity of these two complexes was more than eightfold higher than that of the unfractionated cellulase preparation. A 125,000-Mr glycoprotein with no apparent enzyme activity was the only polypeptide present in all seven complexes. Experiments involving recombination of samples eluted from the ion-exchange chromatography column indicated that synergistic interactions occurred in the hydrolysis of crystalline cellulose by the cellulase system. We propose that the C. papyrosolvens enzyme system responsible for the hydrolysis of crystalline cellulose and xylan is a multicomplex system comprising at least seven diverse protein complexes.

Effect of carbon source on the cellulosomal subpopulations of Clostridium cellulovorans

“…These complexes were co-eluted from a gel-filtration column in a high-molecular-mass fraction (>400 kDa), 'cellulosomal population', and separated by subjecting the high-molecular-mass fraction to anion-exchange chromatography. The elution profiles (subpopulations) obtained from anion-exchange chromatography showed that the cellulosome population was heterogeneous, in agreement with previous studies (Murashima et al, 2002a;Pohlschroder et al, 1994).…”

“…Recent transcriptional and proteomic studies show that different carbon sources in the C. cellulovorans culture medium have a significant effect on cellulosomal enzymic composition and activity (Han et al, 2003a(Han et al, , b, 2004b. Previously, Pohlschroder et al (1994Pohlschroder et al ( , 1995 found that the extracellular cellulase system of Clostridium papyrosolvens consisted of at least seven distinct high-molecular-mass protein complexes (500-660 kDa). All the complexes had endoglucanase-active protein subunits, but only two had xylanase-active subunits.…”

Cellulase, Clostridia, and Ethanol

“…In C. papyrosolvens, a mesophilic anaerobe, the cellulase system (53) can be fractionated by ion-exchange chromatography into seven high-molecular-weight multiprotein complexes, with the molecular weights ranging from 500,000 to 600,000. Each complex has a different ultrastructure (269) and a unique profile of enzymatic activities (270). The common protein appearing in each fraction is a glycoprotein (M r ϭ 125,000) that lacks any enzymatic activity.…”

Ultrastructural diversity of the cellulase complexes of Clostridium papyrosolvens C7

“…All seven multiprotein complexes have endoglucanase-active protein subunits, but only two of the complexes have xylanase-active subunits (16). Three of the multiprotein complexes hydrolyze crystalline cellulose (i.e., have Avicelase activity) (16).…”

“…The extracellular cellulase-xylanase system of Clostridium papyrosolvens C7 comprises at least seven distinct high-molecular-weight multiprotein complexes (M r , 500,000 to 660,000), each with different polypeptide compositions and enzymatic properties (16). All seven multiprotein complexes have endoglucanase-active protein subunits, but only two of the complexes have xylanase-active subunits (16).…”