Heterogeneity in the Histidine-brace Copper Coordination Sphere in Auxiliary Activity Family 10 (AA10) Lytic Polysaccharide Monooxygenases.

ABSTRACT: Copper-dependent lytic polysaccharide monooxygenases (LPMOs) are enzymes that oxidatively deconstruct polysaccharides. The active site copper in LPMOs is coordinated by a histidine-brace. This utilizes the amino group and side chain of the N-terminal His residue with the side chain of a second His residue to create a T-shaped arrangement of nitrogen ligands. We report a structural, kinetic, and thermodynamic appraisal of copper binding to the histidine-brace in an auxiliary activity family 10 (AA10) LPMO from Streptomyces lividans (SliLPMO10E). Unexpectedly, we discovered the existence of two apo-SliLPMO10E species in solution that can each bind copper at a single site with distinct kinetic and thermodynamic (exothermic and endothermic) properties. The experimental EPR spectrum of copper-b

SUBMITTER: Chaplin AK 

PROVIDER: S-EPMC4933455 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature