title: Proteomic investigation of the secretome of Cellvibrio japonicus during growth on chitin.
abstract: Studies of the secretomes of microbes grown on insoluble substrates are important for the discovery of novel proteins involved in biomass conversion. However, data in literature and this study indicate that secretome samples tend to be contaminated with cytoplasmic proteins. We have examined the secretome of the Gram-negative soil bacterium Cellvibrio japonicus using a simple plate-based culturing technique that yields samples with high fractions (60-75%) of proteins that are predicted to be secreted. By combining this approach with label-free quantification using the MaxLFQ algorithm, we have mapped and quantified proteins secreted by C. japonicus during growth on α- and β-chitin. Hierarchical clustering of the detected protein quantities revealed groups of up-regulated proteins that include all five putative C. japonicus chitinases as well as a chitin-specific lytic polysaccharide monooxygenase (CjLPMO10A). A small set of secreted proteins were co-regulated with known chitin-specific enzymes, including several with unknown catalytic functions. These proteins provide interesting targets for further studies aimed at unraveling the enzymatic machineries used by C. japonicus for recalcitrant polysaccharide degradation. Studies of chitin degradation indicated that C. japonicus indeed produces an efficient chitinolytic enzyme cocktail. All MS data have been deposited in the ProteomeXchange with the dataset identifier PXD002843 (http://proteomecentral.proteomexchange.org/dataset/PXD002843).
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway.
authors.forename: Tina Rise
authors.initials: TR
authors.lastname: Tuveng
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway.
authors.forename: Magnus Øverlie
authors.initials: MØ
authors.lastname: Arntzen
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway.
authors.forename: Oskar
authors.initials: O
authors.lastname: Bengtsson
authors.affiliation: Department of Biological Sciences, University of Maryland - Baltimore County, Baltimore, MD, USA.
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Gardner
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway.
authors.forename: Gustav
authors.initials: G
authors.lastname: Vaaje-Kolstad
authors.affiliation: Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Aas, Norway.
authors.forename: Vincent G H
authors.initials: VG
authors.lastname: Eijsink
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D020633:Cellvibrio / Q000201:enzymology* / Q000254:growth & development* / Q000378:metabolism; D002686:Chitin / Q000378:metabolism*; D002688:Chitinases / Q000378:metabolism*; D040901:Proteomics / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D002686:Chitin; D002688:Chitinases
keywords: Cellvibrio japonicus; Chitin; Chitinase; Label-free quantification; Microbiology; Secretome