title: Structural basis of the lack of endo-glucanase inhibitory activity of Lupinus albus γ-conglutin.
abstract: Lupin γ-conglutin and soybean BG7S are two legume seed proteins strongly similar to plant endo-β-glucanases inhibitors acting against fungal GH11 and GH12 glycoside hydrolase. However these proteins lack inhibitory activity. Here we describe the conversion of lupin γ-conglutin to an active inhibitor of endo-β-glucanases belonging to GH11 family. A set of γ-conglutin mutants was designed and expressed in Pichia pastoris, along with the wild-type protein. Unexpectedly, this latter was able to inhibit a GH11 enzyme, but not GH12, whereas the mutants were able to modulate the inhibition capacity. In lupin, γ-conglutin is naturally cleaved in two subunits, whereas in P. pastoris it is not. The lack of proteolytic cleavage is one of the reasons at the basis of the inhibitory activity of recombinant γ-conglutin. The results provide new insights about structural features at the basis of the lack of inhibitory activity of wild-type γ-conglutin and its legume homologues.
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy. Electronic address: alessio.scarafoni@unimi.it.
authors.forename: Alessio
authors.initials: A
authors.lastname: Scarafoni
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Consonni
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Pessina
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Balzaretti
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Capraro
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Galanti
authors.affiliation: Department of Food, Environmental and Nutritional Sciences (DeFENS), Università degli Studi di Milano, Milano, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Duranti
mesh_terms: D002480:Cellulase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D031297:Lupinus / Q000201:enzymology* / Q000378:metabolism; D016296:Mutagenesis; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D010940:Plant Proteins; D002480:Cellulase
keywords: Enzyme inhibitors; Mutagenesis; Plant defence; Seed proteins