RESUMEN
The fundamental and assorted roles of ß-1,3-glucans in nature are underpinned on diverse chemistry and molecular structures, demanding sophisticated and intricate enzymatic systems for their processing. In this work, the selectivity and modes of action of a glycoside hydrolase family active on ß-1,3-glucans were systematically investigated combining sequence similarity network, phylogeny, X-ray crystallography, enzyme kinetics, mutagenesis and molecular dynamics. This family exhibits a minimalist and versatile (α/ß)-barrel scaffold, which can harbor distinguishing exo or endo modes of action, including an ancillary-binding site for the anchoring of triple-helical ß-1,3-glucans. The substrate binding occurs via a hydrophobic knuckle complementary to the canonical curved conformation of ß-1,3-glucans or through a substrate conformational change imposed by the active-site topology of some fungal enzymes. Together, these findings expand our understanding of the enzymatic arsenal of bacteria and fungi for the breakdown and modification of ß-1,3-glucans, which can be exploited for biotechnological applications.
Asunto(s)
Glucano 1,3-beta-Glucosidasa/química , Glicósido Hidrolasas/química , beta-Glucanos/química , Secuencia de Aminoácidos/genética , Sitios de Unión/fisiología , Dominio Catalítico/fisiología , Cristalografía por Rayos X/métodos , Glucano 1,3-beta-Glucosidasa/metabolismo , Glucanos/química , Glicósidos/química , Modelos Moleculares , Especificidad por Sustrato/fisiologíaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.