Exoproteome Profiles of Clostridium cellulovorans Grown on Various Carbon Sources

Abstract

The cellulosome is a complex of cellulosomal proteins bound to scaffolding proteins. This complex is considered the most efficient system for cellulose degradation. Clostridium cellulovorans, which is known to produce cellulosomes, changes the composition of its cellulosomes depending on the growth substrates. However, studies have investigated only cellulosomal proteins; profile changes in noncellulosomal proteins have rarely been examined. In this study, we performed a quantitative proteome analysis of the whole exoproteome of C. cellulovorans, including cellulosomal and noncellulosomal proteins, to illustrate how various substrates are efficiently degraded. C. cellulovorans was cultured with cellobiose, xylan, pectin, or phosphoric acid-swollen cellulose (PASC) as the sole carbon source. PASC was used as a cellulose substrate for more accurate quantitative analysis. Using an isobaric tag method and a liquid chromatography mass spectrometer equipped with a long monolithic silica capillary column, 639 proteins were identified and quantified in all 4 samples. Among these, 79 proteins were involved in saccharification, including 35 cellulosomal and 44 noncellulosomal proteins. We compared protein abundance by spectral count and found that cellulosomal proteins were more abundant than noncellulosomal proteins. Next, we focused on the fold change of the proteins depending on the growth substrates. Drastic changes were observed mainly among the noncellulosomal proteins. These results indicate that cellulosomal proteins were primarily produced to efficiently degrade any substrate and that noncellulosomal proteins were specifically produced to optimize the degradation of a particular substrate. This study highlights the importance of noncellulosomal proteins as well as cellulosomes for the efficient degradation of various substrates.

Metabolic engineering of clostridia for the production of chemicals

“…The letters G, R, and M in the in silico model represents the number of genes, reactions, and metabolites, respectively. The corresponding reference is indicated at the end of strain's name. For online version, colors indicate as follows: light blue, C. acetobutylicum ; light orange, C. kluyveri ; light purple, C. cellulolyticum ; light green, C. beijerinckii ; light gray, Clostridium sp.…”

Xylanase B fromClostridium cellulovorans743B: overexpression, purification, crystallization and X-ray diffraction analysis

“…The xynA and xynB genes have been cloned and confirmed to have xylanase activity (Kosugi et al, 2002;Han et al, 2004). Additionally, proteome analysis verified that C. cellulovorans expresses XynA and XynB proteins (Morisaka et al, 2012;Matsui et al, 2013;Esaka et al, 2015;Aburaya et al, 2015). We believe that these two xylanases play an important role in the hydrolysis of the xylan contained in lignocellulose.…”

The Second-Generation Biomethane from Mandarin Orange Peel under Cocultivation with Methanogens and the Armed Clostridium cellulovorans

“…C. cellulovorans degrades not only cellulose but also hemicelluloses consisting of xylose, fructose, galactose, and mannose [14][15][16]. Whole-genome sequencing of C. cellulovorans and the exoproteome profiles revealed 57 cellulosomal proteinencoding genes and 168 secreted-carbohydrase-encoding genes [17,18]. Furthermore, the high degradation ability on plant cell walls has so far been reported [19].…”