Activity, stability and 3-D structure of the Cu(II) form of a chitin-active lytic polysaccharide monooxygenase from Bacillus amyloliquefaciens

TY - JOUR

T1 - Activity, stability and 3-D structure of the Cu(II) form of a chitin-active lytic polysaccharide monooxygenase from Bacillus amyloliquefaciens

AU - Gregory, Rebecca C.

AU - Hemsworth, Glyn Robert

AU - Turkenburg, Johan P.

AU - Hart, Samuel J.

AU - Walton, Paul H.

AU - Davies, Gideon John

N1 - © The Royal Society of Chemistry 2016. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2016/9/7

Y1 - 2016/9/7

N2 - The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo- and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification). In 2013, the structure of an LPMO from Bacillus amyloliquefaciens, BaAA10, was solved with the Cu centre photoreduced to Cu(i) in the X-ray beam. Here we present the catalytic activity of BaAA10. We show that it is a chitin-active LPMO, active on both α and β chitin, with the Cu(ii) binding with low nM KD, and the substrate greatly increasing the thermal stability of the enzyme. A spiral data collection strategy has been used to facilitate access to the previously unobservable Cu(ii) state of the active centre, revealing a coordination geometry around the copper which is distorted from axial symmetry, consistent with the previous findings from EPR spectroscopy.

AB - The enzymatic deconstruction of recalcitrant polysaccharide biomass is central to the conversion of these substrates for societal benefit, such as in biofuels. Traditional models for enzyme-catalysed polysaccharide degradation involved the synergistic action of endo-, exo- and processive glycoside hydrolases working in concert to hydrolyse the substrate. More recently this model has been succeeded by one featuring a newly discovered class of mononuclear copper enzymes: lytic polysaccharide monooxygenases (LPMOs; classified as Auxiliary Activity (AA) enzymes in the CAZy classification). In 2013, the structure of an LPMO from Bacillus amyloliquefaciens, BaAA10, was solved with the Cu centre photoreduced to Cu(i) in the X-ray beam. Here we present the catalytic activity of BaAA10. We show that it is a chitin-active LPMO, active on both α and β chitin, with the Cu(ii) binding with low nM KD, and the substrate greatly increasing the thermal stability of the enzyme. A spiral data collection strategy has been used to facilitate access to the previously unobservable Cu(ii) state of the active centre, revealing a coordination geometry around the copper which is distorted from axial symmetry, consistent with the previous findings from EPR spectroscopy.

UR - http://www.scopus.com/inward/record.url?scp=84994035446&partnerID=8YFLogxK

U2 - 10.1039/c6dt02793h

DO - 10.1039/c6dt02793h

M3 - Article

AN - SCOPUS:84994035446

SN - 1477-9226

VL - 45

SP - 16904

EP - 16912

JO - Dalton Transactions

JF - Dalton Transactions

IS - 42

ER -