Methylation of the N-terminal histidine protects a lytic polysaccharide monooxygenase from auto-oxidative inactivation.

ABSTRACT: The catalytically crucial N-terminal histidine (His1) of fungal lytic polysaccharide monooxygenases (LPMOs) is post-translationally modified to carry a methylation. The functional role of this methylation remains unknown. We have carried out an in-depth functional comparison of two variants of a family AA9 LPMO from Thermoascus aurantiacus (TaLPMO9A), one with, and one without the methylation on His1. Various activity assays showed that the two enzyme variants are identical in terms of substrate preferences, cleavage specificities and the ability to activate molecular oxygen. During the course of this work, new functional features of TaLPMO9A were discovered, in particular the ability to cleave xyloglucan, and these features were identical for both variants. Using a variety of techniques,

SUBMITTER: Petrovic DM 

PROVIDER: S-EPMC6194291 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature