title: Functional metagenomics unveils a multifunctional glycosyl hydrolase from the family 43 catalysing the breakdown of plant polymers in the calf rumen.
abstract: Microbial communities from cow rumen are known for their ability to degrade diverse plant polymers at high rates. In this work, we identified 15 hydrolases through an activity-centred metagenome analysis of a fibre-adherent microbial community from dairy cow rumen. Among them, 7 glycosyl hydrolases (GHs) and 1 feruloyl esterase were successfully cloned, expressed, purified and characterised. The most striking result was a protein of GH family 43 (GHF43), hereinafter designated as R_09-02, which had characteristics very distinct from the other proteins in this family with mono-functional β-xylosidase, α-xylanase, α-L-arabinase and α-L-arabinofuranosidase activities. R_09-02 is the first multifunctional enzyme to exhibit β-1,4 xylosidase, α-1,5 arabinofur(pyr)anosidase, β-1,4 lactase, α-1,6 raffinase, α-1,6 stachyase, β-galactosidase and α-1,4 glucosidase activities. The R_09-02 protein appears to originate from the chromosome of a member of Clostridia, a class of phylum Firmicutes, members of which are highly abundant in ruminal environment. The evolution of R_09-02 is suggested to be driven from the xylose- and arabinose-specific activities, typical for GHF43 members, toward a broader specificity to the glucose- and galactose-containing components of lignocellulose. The apparent capability of enzymes from the GHF43 family to utilise xylose-, arabinose-, glucose- and galactose-containing oligosaccharides has thus far been neglected by, or could not be predicted from, genome and metagenome sequencing data analyses. Taking into account the abundance of GHF43-encoding gene sequences in the rumen (up to 7% of all GH-genes) and the multifunctional phenotype herein described, our findings suggest that the ecological role of this GH family in the digestion of ligno-cellulosic matter should be significantly reconsidered.
authors: CSIC, Institute of Catalysis, Madrid, Spain. mferrer@icp.csic.es
authors: Manuel
authors: M
authors: Ferrer
authors: Azam
authors: A
authors: Ghazi
authors: Ana
authors: A
authors: Beloqui
authors: José María
authors: JM
authors: Vieites
authors: Nieves
authors: N
authors: López-Cortés
authors: Julia
authors: J
authors: Marín-Navarro
authors: Taras Y
authors: TY
authors: Nechitaylo
authors: María-Eugenia
authors: ME
authors: Guazzaroni
authors: Julio
authors: J
authors: Polaina
authors: Agnes
authors: A
authors: Waliczek
authors: Tatyana N
authors: TN
authors: Chernikova
authors: Oleg N
authors: ON
authors: Reva
authors: Olga V
authors: OV
authors: Golyshina
authors: Peter N
authors: PN
authors: Golyshin
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D006026:Glycoside Hydrolases / Q000235:genetics* / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D056186:Metagenomics; D008958:Models, Molecular; D010802:Phylogeny; D010944:Plants / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism*; D011487:Protein Conformation; D012417:Rumen / Q000201:enzymology*
chemical_list: D011108:Polymers; C036909:lignocellulose; D008031:Lignin; D006026:Glycoside Hydrolases