Exploring the\nStructural, Biochemical, and Functional\nDiversity of Glycoside Hydrolase Family 12 from <i>Penicillium\nsubrubescens</i>

Glycoside hydrolases\n(GHs) play an essential role in\nplant biomass\ndegradation and modification for the sustainable production of biochemicals.\nThe filamentous Ascomycete fungus <i>Penicillium subrubescens</i> contains a higher number of GH12 candidates compared to related\nspecies. Therefore, we aimed to compare <i>P. subrubescens</i> GH12s for their ability and substrate specificity for plant cell\nwall polysaccharide degradation and species’ potential as a\nsource of novel enzymes for plant biomass valorization. Our re-evaluated\nphylogenetic analysis of fungal GH12 members showed that the <i>P. subrubescens</i> GH12s were located in different (new) clades.\nBiochemical characterization marked <i>Ps</i>EglA as an\nendoglucanase and four other <i>P. subrubescens</i> GH12s\n(i.e., <i>Ps</i>XegA–D) as xyloglucanases. Interestingly,\nstructural features of <i>Ps</i>XegD and <i>Ps</i>XegE were more comparable to those of Basidiomycete GH12 xyloglucanases\nwith a unique open substrate-binding cleft. <i>Ps</i>UegA\ndisplayed dual xyloglucanase and endoglucanase activity and also showed\ndistinct structural features. Comparative transcriptome analysis supported\nthe functional diversity of <i>P. subrubescens</i> GH12s\nin plant biomass degradation. The gene encoding <i>Ps</i>UegA was expressed under diverse conditions, suggesting a scouting\nrole for this enzyme.