Label-free quantitative proteomics for the extremely thermophilic bacterium caldicellulosiruptor obsidiansis reveal distinct abundance patterns upon growth on cellobiose, crystalline cellulose, and switchgrass

Journal
Journal of proteome research  
Volume
10
Issue
12
Start Page
5302
End Page
5314
Citation
Journal of Proteome Research 10 (12): 5302-5314 (2011)
Publisher DOI
10.1021/pr200536j
Scopus ID
2-s2.0-82755184968
PubMed ID
21988591
Publisher
ACS Publications
Mass spectrometric analysis of Caldicellulosiruptor obsidiansis cultures grown on four different carbon sources identified 65% of the cells' predicted proteins in cell lysates and supernatants. Biological and technical replication together with sophisticated statistical analysis were used to reliably quantify protein abundances and their changes as a function of carbon source. Extracellular, multifunctional glycosidases were significantly more abundant on cellobiose than on the crystalline cellulose substrates Avicel and filter paper, indicating either disaccharide induction or constitutive protein expression. Highly abundant flagellar, chemotaxis, and pilus proteins were detected during growth on insoluble substrates, suggesting motility or specific substrate attachment. The highly abundant extracellular binding protein COB47-0549 together with the COB47-1616 ATPase might comprise the primary ABC-transport system for cellooligosaccharides, while COB47-0096 and COB47-0097 could facilitate monosaccharide uptake. Oligosaccharide degradation can occur either via extracellular hydrolysis by a GH1 β-glycosidase or by intracellular phosphorolysis using two GH94 enzymes. When C. obsidiansis was grown on switchgrass, the abundance of hemicellulases (including GH3, GH5, GH51, and GH67 enzymes) and certain sugar transporters increased significantly. Cultivation on biomass also caused a concerted increase in cytosolic enzymes for xylose and arabinose fermentation. © 2011 American Chemical Society.
Subjects
bioenergy research
microbial cellulose degradation
microbial proteomics
quantitative proteomics
thermophilic bacteria
DDC Class
570: Biowissenschaften, Biologie