Biochemical evidence of both copper chelation and oxygenase activity at the histidine brace

Søren Brander, Istvan Horvath, Johan Ø Ipsen, Ausra Peciulyte, Lisbeth Olsson, Cristina Hernández Rollán, Morten Nørholm, Susanne Mossin, Leila Lo Leggio, Corinna Probst, Dennis J Thiele, Katja S Johansen*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Lytic polysaccharide monooxygenase (LPMO) and copper binding protein CopC share a similar mononuclear copper site. This site is defined by an N-terminal histidine and a second internal histidine side chain in a configuration called the histidine brace. To understand better the determinants of reactivity, the biochemical and structural properties of a well-described cellulose-specific LPMO from Thermoascus aurantiacus (TaAA9A) is compared with that of CopC from Pseudomonas fluorescens (PfCopC) and with the LPMO-like protein Bim1 from Cryptococcus neoformans. PfCopC is not reduced by ascorbate but is a very strong Cu(II) chelator due to residues that interacts with the N-terminus. This first biochemical characterization of Bim1 shows that it is not redox active, but very sensitive to H2O2, which accelerates the release of Cu ions from the protein. TaAA9A oxidizes ascorbate at a rate similar to free copper but through a mechanism that produce fewer reactive oxygen species. These three biologically relevant examples emphasize the diversity in how the proteinaceous environment control reactivity of Cu with O2.

Original languageEnglish
Article number16369
JournalScientific Reports
Volume10
Issue number1
Number of pages11
ISSN2045-2322
DOIs
Publication statusPublished - 2020

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