title: His22 of TLXI plays a critical role in the inhibition of glycoside hydrolase family 11 xylanases.
abstract: Recently, a novel wheat thaumatin-like protein, TLXI, which inhibits microbial glycoside hydrolase family (GH) 11 xylanases has been identified. It is the first xylanase inhibitor that exerts its inhibition in a non-competitive way. In the present study we gained insight into the interaction between TLXI and xylanases via combined molecular modeling and mutagenic approaches. More specifically, site-specific mutation of His22, situated on a loop which distinguishes TLXI from other, non-inhibiting, thaumatin-like proteins, and subsequent expression of the mutant in Pichia pastoris resulted in a protein lacking inhibition capacity. The mutant protein was unable to form a complex with GH11 xylanases. Based on these findings, the interaction of TLXI with GH11 xylanases is discussed.
authors.affiliation: Laboratory of Gene Technology, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Rombouts
authors.forename: Ellen
authors.initials: E
authors.lastname: Fierens
authors.forename: Elien
authors.initials: E
authors.lastname: Vandermarliere
authors.forename: Arnout
authors.initials: A
authors.lastname: Voet
authors.forename: Kurt
authors.initials: K
authors.lastname: Gebruers
authors.forename: Johnny
authors.initials: J
authors.lastname: Beaugrand
authors.forename: Christophe M
authors.initials: CM
authors.lastname: Courtin
authors.forename: Jan A
authors.initials: JA
authors.lastname: Delcour
authors.forename: Marc
authors.initials: M
authors.lastname: de Maeyer
authors.forename: Anja
authors.initials: A
authors.lastname: Rabijns
authors.forename: Steven
authors.initials: S
authors.lastname: Van Campenhout
authors.forename: Guido
authors.initials: G
authors.lastname: Volckaert
mesh_terms: D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases / Q000037:antagonists & inhibitors*; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors; D006639:Histidine; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D011485:Protein Binding; D014908:Triticum
chemical_list: D010940:Plant Proteins; D006639:Histidine; C003427:thaumatin protein, plant; D006026:Glycoside Hydrolases; D043364:Endo-1,4-beta Xylanases