title: Exploring the functional soil-microbe interface and exoenzymes through soil metaexoproteomics.
abstract: Functionally important proteins at the interface of cell and soil are of potentially low abundance when compared with commonly recovered intracellular proteins. A novel approach was developed and used to extract the metaexoproteome, the subset of proteins found outside the cell, in the context of a soil enriched with the nitrogen-containing recalcitrant polymer chitin. The majority of proteins recovered was of bacterial origin and localized to the outer membrane or extracellular milieu. A wide variety of transporter proteins were identified, particularly those associated with amino-acid and phosphate uptake. The metaexoproteome extract retained chitinolytic activity and we were successful in detecting Nocardiopsis-like chitinases that correlated with the glycoside hydrolase family 18 (GH18) chi gene data and metataxonomic analysis. Nocardiopsis-like chitinases appeared to be solely responsible for chitinolytic activity in soil. This is the first study to detect and sequence bacterial exoenzymes with proven activity in the soil enzyme pool.
authors.affiliation: School of Life Sciences, University of Warwick, Coventry, UK.
authors.forename: Ashley S
authors.initials: AS
authors.lastname: Johnson-Rollings
authors.affiliation: School of Life Sciences, University of Warwick, Coventry, UK.
authors.forename: Helena
authors.initials: H
authors.lastname: Wright
authors.affiliation: Istituto per lo Studio degli Ecosistemi, CNR, Pisa, Italy.
authors.forename: Grazia
authors.initials: G
authors.lastname: Masciandaro
authors.affiliation: Istituto per lo Studio degli Ecosistemi, CNR, Pisa, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Macci
authors.affiliation: Istituto per lo Studio degli Ecosistemi, CNR, Pisa, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Doni
authors.affiliation: School of Life Sciences, University of Warwick, Coventry, UK.
authors.forename: Leo A
authors.initials: LA
authors.lastname: Calvo-Bado
authors.affiliation: School of Life Sciences, University of Warwick, Coventry, UK.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Slade
authors.affiliation: Grupo de Biotecnología, CEIEB, IFAL, Universidad de La Habana, Havana, Cuba.
authors.forename: Carlos
authors.initials: C
authors.lastname: Vallin Plou
authors.affiliation: School of Life Sciences, University of Warwick, Coventry, UK.
authors.forename: Elizabeth M H
authors.initials: EM
authors.lastname: Wellington
mesh_terms: D001419:Bacteria / Q000145:classification / Q000201:enzymology*; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000032:analysis* / Q000378:metabolism; D040901:Proteomics; D012988:Soil Microbiology
chemical_list: D002686:Chitin; D002688:Chitinases