title: Profile of secreted hydrolases, associated proteins, and SlpA in Thermoanaerobacterium saccharolyticum during the degradation of hemicellulose.
abstract: Thermoanaerobacterium saccharolyticum, a Gram-positive thermophilic anaerobic bacterium, grows robustly on insoluble hemicellulose, which requires a specialized suite of secreted and transmembrane proteins. We report here the characterization of proteins secreted by this organism. Cultures were grown on hemicellulose, glucose, xylose, starch, and xylan in pH-controlled bioreactors, and samples were analyzed via spotted microarrays and liquid chromatography-mass spectrometry. Key hydrolases and transporters employed by T. saccharolyticum for growth on hemicellulose were, for the most part, hitherto uncharacterized and existed in two clusters (Tsac_1445 through Tsac_1464 for xylan/xylose and Tsac_1344 through Tsac_1349 for starch). A phosphotransferase system subunit, Tsac_0032, also appeared to be exclusive to growth on glucose. Previously identified hydrolases that showed strong conditional expression changes included XynA (Tsac_1459), XynC (Tsac_0897), and a pullulanase, Apu (Tsac_1342). An omnipresent transcript and protein making up a large percentage of the overall secretome, Tsac_0361, was tentatively identified as the primary S-layer component in T. saccharolyticum, and deletion of the Tsac_0361 gene resulted in gross morphological changes to the cells. The view of hemicellulose degradation revealed here will be enabling for metabolic engineering efforts in biofuel-producing organisms that degrade cellulose well but lack the ability to catabolize C5 sugars.
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA Mascoma Corporation, Lebanon, New Hampshire, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Currie
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Guss
authors.affiliation: Mascoma Corporation, Lebanon, New Hampshire, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Herring
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Giannone
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Johnson
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: P K
authors.initials: PK
authors.lastname: Lankford
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Brown
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Hettich
authors.affiliation: Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire, USA Mascoma Corporation, Lebanon, New Hampshire, USA lee.r.lynd@dartmouth.edu.
authors.forename: L R
authors.initials: LR
authors.lastname: Lynd
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D021381:Protein Transport; D046950:Thermoanaerobacterium / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011134:Polysaccharides; C007916:hemicellulose; D006867:Hydrolases