title: Characterization of the subunits in an apparently homogeneous subpopulation of Clostridium thermocellum cellulosomes.
abstract: Clostridium thermocellum cellulosomes isolated by cellulose affinity chromatography were fractionated by anion exchange chromatography into apparently homogeneous subpopulation that differed with respect to enzyme activity and subunit composition. One such subpopulation contained predominantly six subunits and was closely similar to the "subcellulosome" described by Kobayashi et al. (Kobayashi, T., Romaniec, M. P. M., Fauth, U., and Demain, A. L., Appl. Environ. Microbiol., 1990, 56, 3040-3046). Avicelase specific activity of this homogeneous subpopulation was slightly higher than that of unfractionated cellulosomes, but the two preparations were similarly affected by Ca2+, dithiothreitol, and cellobiose. Determination of their N-terminal sequences and enzyme activities has enabled three of the six major subunits of the subpopulation of cellulosomes to be positively identified as known components of the C. thermocellum cellulase complex; the other three subunits did not match up with previously characterized cellulosomal proteins.
authors.affiliation: Research School of Biosciences, Biological Laboratory, University of Kent, United Kingdom.
authors.forename: B R
authors.initials: BR
authors.lastname: Ali
authors.forename: M P
authors.initials: MP
authors.lastname: Romaniec
authors.forename: G P
authors.initials: GP
authors.lastname: Hazlewood
authors.forename: R B
authors.initials: RB
authors.lastname: Freedman
mesh_terms: D000595:Amino Acid Sequence; D002118:Calcium / Q000494:pharmacology; D002475:Cellobiose / Q000494:pharmacology; D002480:Cellulase / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D002482:Cellulose / Q000378:metabolism*; D002845:Chromatography; D003013:Clostridium / Q000201:enzymology*; D004229:Dithiothreitol / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000378:metabolism; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D017421:Sequence Analysis; D013347:Subcellular Fractions
chemical_list: D046911:Macromolecular Substances; D002475:Cellobiose; D002482:Cellulose; D004492:Edetic Acid; D006026:Glycoside Hydrolases; D002480:Cellulase; D002118:Calcium; D004229:Dithiothreitol