Redefining XynA from Penicillium funiculosum IMI 378536 as a GH7 cellobiohydrolase - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Industrial Microbiology and Biotechnology Année : 2012

Redefining XynA from Penicillium funiculosum IMI 378536 as a GH7 cellobiohydrolase

Résumé

The secretome of Penicillium funiculosum contains two family GH7 enzymes, one of which (designated XynA) has been described as a xylanase. This is unusual because it is the only xylanase in family GH7, which is mainly composed of cellobiohydrolases and endoglucanases, and also because XynA is highly similar to the cellobiohydrolase I from Talaromyces emersonii and Trichoderma reesei (72 and 65 % identity, respectively). To probe this enigma, we investigated the biochemical properties of XynA, notably its activity on xylans and beta-d-glucans. A highly pure sample of XynA was obtained and used to perform hydrolysis tests on polysaccharides. These revealed that XynA is 100-fold more active on beta-1,4-glucan than on xylan. Likewise, XynA was active on both 4-nitrophenyl-beta-d-lactopyranoside (pNP-beta-d-Lac) and 4-nitrophenyl-beta-d-cellobioside (pNP-cellobiose), which shows that XynA is principally an exo-acting type 1 cellobiohydrolase enzyme that displays 5.2-fold higher performance on pNP-cellobiose than on pNP-beta-d-Lac. Finally, analyses performed using cellodextrins as substrate revealed that XynA mainly produced cellobiose (C2) from substrates containing three or more glucosyl subunits, and that C2 inhibits XynA at high concentrations (IC50 (C2) = 17.7 mu M). Overall, this study revealed that XynA displays typical cellobiohydrolase 1 activity and confirms that the description of this enzyme in public databases should be definitively amended. Moreover, the data provided here complete the information provided by a previous proteomics investigation and reveal that P. funiculosum secretes a complete set of cellulose-degrading enzymes.

Dates et versions

hal-01268269 , version 1 (04-02-2016)

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Citer

Hélène Texier, Claire Dumon, Virginie Neugnot-Roux, Marc Maestracci, Michael O'Donohue. Redefining XynA from Penicillium funiculosum IMI 378536 as a GH7 cellobiohydrolase. Journal of Industrial Microbiology and Biotechnology, 2012, 39 (11), pp.1569 - 1576. ⟨10.1007/s10295-012-1166-1⟩. ⟨hal-01268269⟩
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