Ferrer, ManuelGhazi, AzamBeloqui, AnaVieites, Jose MarıaLopez-Cortes, NievesMarın-Navarro, JuliaNechitaylo, Taras Y.Guazzaroni, Marıa-EugeniaPolaina, JulioWaliczek, AgnesChernikova, Tatyana N.Reva, Oleg N.Golyshina, Olga V.Golyshin, Peter N.2012-08-302012-08-302012-06-25Ferrer M, Ghazi A, Beloqui A, Vieites JM, Lopez-Cortes N, et al. (2012) Functional Metagenomics Unveils a Multifunctional Glycosyl Hydrolase from the Family 43 Catalysing the Breakdown of Plant Polymers in the Calf Rumen. PLoS ONE 7(6): e38134. DOI: 10.1371/journal.pone.0038134.1932-620310.1371/journal.pone.0038134http://hdl.handle.net/2263/19683Microbial 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 bxylosidase, a-xylanase, a-L-arabinase and a-L-arabinofuranosidase activities. R_09-02 is the first multifunctional enzyme to exhibit b-1,4 xylosidase, a-1,5 arabinofur(pyr)anosidase, b-1,4 lactase, a-1,6 raffinase, a-1,6 stachyase, b-galactosidase and a- 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.en© 2012 Ghazi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License.Calf rumenBreakdown of plant polymersArticle