Global View of the Clostridium thermocellum Cellulosome Revealed by Quantitative Proteomic Analysis
- 1 October 2007
- journal article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 189 (19), 6787-6795
- https://doi.org/10.1128/jb.00882-07
Abstract
A metabolic isotope-labeling strategy was used in conjunction with nano-liquid chromatography-electrospray ionization mass spectrometry peptide sequencing to assess quantitative alterations in the expression patterns of subunits within cellulosomes of the cellulolytic bacterium Clostridium thermocellum, grown on either cellulose or cellobiose. In total, 41 cellulosomal proteins were detected, including 36 type I dockerin-containing proteins, which count among them all but three of the known docking components and 16 new subunits. All differential expression data were normalized to the scaffoldin CipA such that protein per cellulosome was compared for growth between the two substrates. Proteins that exhibited higher expression in cellulosomes from cellulose-grown cells than in cellobiose-grown cells were the cell surface anchor protein OlpB, exoglucanases CelS and CelK, and the glycoside hydrolase family 9 (GH9) endoglucanase CelJ. Conversely, lower expression in cellulosomes from cells grown on cellulose than on cellobiose was observed for the GH8 endoglucanase CelA; GH5 endoglucanases CelB, CelE, CelG; and hemicellulases XynA, XynC, XynZ, and XghA. GH9 cellulases were the most abundant group of enzymes per CipA when cells were grown on cellulose, while hemicellulases were the most abundant group on cellobiose. The results support the existing theory that expression of scaffoldin-related proteins is coordinately regulated by a catabolite repression type of mechanism, as well as the prior observation that xylanase expression is subject to a growth rate-independent type of regulation. However, concerning transcriptional control of cellulases, which had also been previously shown to be subject to catabolite repression, a novel distinction was observed with respect to endoglucanases.Keywords
This publication has 69 references indexed in Scilit:
- Locating proteins in the cell using TargetP, SignalP and related toolsNature Protocols, 2007
- Use of Peptide Retention Time Prediction for Protein Identification by off-line Reversed-Phase HPLC−MALDI MS/MSAnalytical Chemistry, 2006
- The functional repertoire of prokaryote cellulosomes includes the serpin superfamily of serine proteinase inhibitorsMolecular Microbiology, 2006
- Regulation of Major Cellulosomal Endoglucanases of Clostridium thermocellum Differs from That of a Prominent Cellulosomal XylanaseJournal of Bacteriology, 2005
- Regulation of Cellulase Synthesis in Batch and Continuous Cultures of Clostridium thermocellumJournal of Bacteriology, 2005
- Regulation of Expression of Scaffoldin-Related Genes in Clostridium thermocellumJournal of Bacteriology, 2003
- Regulation of the Cellulosomal celS ( cel48A ) Gene of Clostridium thermocellum Is Growth Rate DependentJournal of Bacteriology, 2003
- Chi18A, the Endochitinase in the Cellulosome of the Thermophilic, Cellulolytic Bacterium Clostridium thermocellumApplied and Environmental Microbiology, 2002
- Analysis of a ribose transport operon from Bacillus subtilisMicrobiology, 1994
- Purification and cellulosomal localization ofClostridium thermocellum mixed linkage ?-glucanase LicB (1,3?1,4-?-D-glucanase)Biotechnology Letters, 1994