Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, Department of Chemistry, University of Texas at Austin, Austin, TX 78712
Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801
Department of Chemistry, University of Texas at Austin, Austin, TX 78712
Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801
The “Histidine-brace” (His-brace) copper-binding site, composed of Cu(His) 2 with a backbone amine, is found in metalloproteins with diverse functions. A primary example is lytic polysaccharide monooxygenase (LPMO), a class of enzymes that catalyze the oxidative depolymerization of polysaccharides, providing not only an energy source for native microorganisms but also a route to more effective industrial biomass conversion. Despite its importance, how the Cu His-brace site performs this unique and challenging oxidative depolymerization reaction remains to be understood. To answer this question, we have designed a biosynthetic model of LPMO by incorporating the Cu His-brace motif into azurin, an electron transfer protein. Spectroscopic studies, including ultraviolet-visible (UV–Vis) absorption and electron paramagnetic resonance, confirm copper binding at the designed His-brace site. Moreover, the designed protein is catalytically active towards both cellulose and starch, the native substrates of LPMO, generating degraded oligosaccharides with multiturnovers by C1 oxidation. It also performs oxidative cleavage of the model substrate 4-nitrophenyl-D-glucopyranoside, achieving a turnover number ~9% of that of a native LPMO assayed under identical conditions. This work presents a rationally designed artificial metalloenzyme that acts as a structural and functional mimic of LPMO, which provides a promising system for understanding the role of the Cu His-brace site in LPMO activity and potential application in polysaccharide degradation.
Liu, Yiwei, et al. "A designed Copper Histidine-brace enzyme for oxidative depolymerization of polysaccharides as a model of lytic polysaccharide monooxygenase." Proceedings of the National Academy of Sciences of the United States of America, vol. 120, no. 43, Oct. 2023. https://doi.org/10.1073/pnas.2308286120
Liu, Yiwei, Harnden, Kevin A., Van Stappen, Casey, Dikanov, Sergei A., & Lu, Yi (2023). A designed Copper Histidine-brace enzyme for oxidative depolymerization of polysaccharides as a model of lytic polysaccharide monooxygenase. Proceedings of the National Academy of Sciences of the United States of America, 120(43). https://doi.org/10.1073/pnas.2308286120
Liu, Yiwei, Harnden, Kevin A., Van Stappen, Casey, et al., "A designed Copper Histidine-brace enzyme for oxidative depolymerization of polysaccharides as a model of lytic polysaccharide monooxygenase," Proceedings of the National Academy of Sciences of the United States of America 120, no. 43 (2023), https://doi.org/10.1073/pnas.2308286120
@article{osti_2202499,
author = {Liu, Yiwei and Harnden, Kevin A. and Van Stappen, Casey and Dikanov, Sergei A. and Lu, Yi},
title = {A designed Copper Histidine-brace enzyme for oxidative depolymerization of polysaccharides as a model of lytic polysaccharide monooxygenase},
annote = { The “Histidine-brace” (His-brace) copper-binding site, composed of Cu(His) 2 with a backbone amine, is found in metalloproteins with diverse functions. A primary example is lytic polysaccharide monooxygenase (LPMO), a class of enzymes that catalyze the oxidative depolymerization of polysaccharides, providing not only an energy source for native microorganisms but also a route to more effective industrial biomass conversion. Despite its importance, how the Cu His-brace site performs this unique and challenging oxidative depolymerization reaction remains to be understood. To answer this question, we have designed a biosynthetic model of LPMO by incorporating the Cu His-brace motif into azurin, an electron transfer protein. Spectroscopic studies, including ultraviolet-visible (UV–Vis) absorption and electron paramagnetic resonance, confirm copper binding at the designed His-brace site. Moreover, the designed protein is catalytically active towards both cellulose and starch, the native substrates of LPMO, generating degraded oligosaccharides with multiturnovers by C1 oxidation. It also performs oxidative cleavage of the model substrate 4-nitrophenyl-D-glucopyranoside, achieving a turnover number ~9% of that of a native LPMO assayed under identical conditions. This work presents a rationally designed artificial metalloenzyme that acts as a structural and functional mimic of LPMO, which provides a promising system for understanding the role of the Cu His-brace site in LPMO activity and potential application in polysaccharide degradation. },
doi = {10.1073/pnas.2308286120},
url = {https://www.osti.gov/biblio/2202499},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
issn = {ISSN 0027-8424},
number = {43},
volume = {120},
place = {United States},
publisher = {Proceedings of the National Academy of Sciences},
year = {2023},
month = {10}}
University of Illinois at Urbana-Champaign, IL (United States)
Sponsoring Organization:
National Institutes of Health (NIH); National Science Foundation (NSF); Robert. A. Welch Foundation; USDOE; USDOE Office of Science (SC)
Grant/Contract Number:
FG02-08ER15960
OSTI ID:
2202499
Alternate ID(s):
OSTI ID: 2472272
Journal Information:
Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 43 Vol. 120; ISSN 0027-8424