Mutational analysis of endoxylanases XylA and XylB from the phytopathogen Fusarium graminearum reveals comprehensive insights into their inhibitor insensitivity.

ABSTRACT: Endo-beta-1,4-xylanases (EC 3.2.1.8; endoxylanases), key enzymes in the degradation of xylan, are considered to play an important role in phytopathogenesis, as they occupy a prominent position in the arsenal of hydrolytic enzymes secreted by phytopathogens to breach the cell wall and invade the plant tissue. Plant endoxylanase inhibitors are increasingly being pinpointed as part of a counterattack mechanism. To understand the surprising XIP-type endoxylanase inhibitor insensitivity of endoxylanases XylA and XylB from the phytopathogen Fusarium graminearum, an extensive mutational study of these enzymes was performed. Using combinatorial and site-directed mutagenesis, the XIP insensitivity of XylA as well as XylB was proven to be solely due to amino acid sequence adaptations in the "thumb"

SUBMITTER: Belien T 

PROVIDER: S-EPMC1932832 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature