Crystal structures of a dodecameric multicopper oxidase from Marinithermus hydrothermalis. Issue 10 (4th October 2021)

• Record Type: Journal Article
• Authors: Paavola, Joseph L.; Battistin, Umberto; Ogata, Craig M.; Georgiadis, Millie M.
• Is Part Of: Acta crystallographica. Volume 77:Issue 10(2021)
• Page Start: 1336
• Page End: 1345
• Publication Date: 2021-10-04
• Subjects: crystal structure -- Marinithermus hydrothermalis -- multicopper oxidases -- laccases -- thermophiles -- dodecamers; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; Molecular biology -- Periodicals; Molecular structure -- Periodicals; Biomolecules -- Structure -- Periodicals; Cytology -- Periodicals; Biomolecules -- Structure; Crystallography; Cytology; Molecular biology; Molecular structure; X-ray crystallography; Periodicals; 548
• DOI: 10.1107/S205979832100944X
• Languages: English
• ISSNs: 2059-7983

Abstract

Abstract : A two‐domain multicopper oxidase (MCO) from Marinithermus hydrothermalis functions as a laccase and was crystallized in two distinct lattices as a dodecameric ball‐like structure. Crystal structures are reported in cubic and orthorhombic lattices at 1.92 and 2.36 Å resolution, respectively. This MCO forms trimers similar to those found in other two‐domain MCOs, but is unique in forming a higher order dodecameric structure. Abstract : Multicopper oxidases (MCOs) represent a diverse family of enzymes that catalyze the oxidation of either an organic or a metal substrate with concomitant reduction of dioxygen to water. These enzymes contain variable numbers of cupredoxin domains, two, three or six per subunit, and rely on four copper ions, a single type I copper and three additional copper ions organized in a trinuclear cluster (TNC), with one type II and two type III copper ions, to catalyze the reaction. Here, two crystal structures and the enzymatic characterization of Marinithermus hydrothermalis MCO, a two‐domain enzyme, are reported. This enzyme decolorizes Congo Red dye at 70°C in the presence of high halide concentrations and may therefore be useful in the detoxification of industrial waste that contains dyes. In two distinct crystal structures, MhMCO forms the trimers seen in other two‐domain MCOs, but differs from these enzymes in that four trimers interact to create a dodecamer. This dodecamer of MhMCO forms a closed ball‐like structure and has implications for the sequestration of bound divalent metal ions as well as substrate accessibility. In each subunit of the dodecameric structures, a Trp residue, Trp351, located between the type I and TNC sites exists in two distinct conformations, consistent with a potential role in facilitating electron transfer in the enzyme.