Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules
Abstract Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two‐centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enz...
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Wiley-VCH
2024-12-01
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| Online Access: | https://doi.org/10.1002/open.202400190 |
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| author | Henrik Bohr Irene Shim Jens Ulstrup Xinxin Xiao |
| author_facet | Henrik Bohr Irene Shim Jens Ulstrup Xinxin Xiao |
| author_sort | Henrik Bohr |
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| description | Abstract Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two‐centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enzymes show no non‐turnover voltammetry on Au(111)‐surfaces modified by thiol based self‐assembled molecular monolayers, but dioxygen or nitrite substrate triggers strong electrocatalytic signals. Scanning tunnelling microscopy also shows high conductivity only when dioxygen or nitrite is present. Atomic force microscopy shows constant CuNIR height but pronounced structural expansion in the electrocatalytic range on nitrite binding. We have recently offered a rationale, based on ab initio quantum chemical studies of water/nitrite substitution in a 740‐atom CuNIR fragment. Presently we provide much more detailed structural assignment mapped to single‐residue resolution. NO2−‐binding induces both a 2 Å Cu−Cu distance increase, and pronounced frontier orbital delocalization strongly facilitating ET between the Cu regions. The conformational changes transmit from the catalytic Type II centre to the electron inlet Type I centre, via the His129‐Cys130 ligands, and via Type I–Cys130 or Type I‐His129 ending at Type II Asp92. The ET patterns are reflected in different atomic Mulliken charges in the water and nitrite CuNIR fragment. |
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| institution | Kabale University |
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| spelling | doaj-art-48215e85b88c4f2095d6e82ea6e00ea42024-12-09T07:59:38ZengWiley-VCHChemistryOpen2191-13632024-12-011312n/an/a10.1002/open.202400190Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate MoleculesHenrik Bohr0Irene Shim1Jens Ulstrup2Xinxin Xiao3Department of Chemical Engineering Technical University of Denmark Building 229, Kemitorvet DK-2800 Kgs. Lyngby DenmarkDepartment of Chemistry Technical University of Denmark,Building 207, Kemitorvet DK-2800 Kgs. Lyngby DenmarkDepartment of Chemistry Technical University of Denmark,Building 207, Kemitorvet DK-2800 Kgs. Lyngby DenmarkDepartment of Chemistry Technical University of Denmark,Building 207, Kemitorvet DK-2800 Kgs. Lyngby DenmarkAbstract Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two‐centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enzymes show no non‐turnover voltammetry on Au(111)‐surfaces modified by thiol based self‐assembled molecular monolayers, but dioxygen or nitrite substrate triggers strong electrocatalytic signals. Scanning tunnelling microscopy also shows high conductivity only when dioxygen or nitrite is present. Atomic force microscopy shows constant CuNIR height but pronounced structural expansion in the electrocatalytic range on nitrite binding. We have recently offered a rationale, based on ab initio quantum chemical studies of water/nitrite substitution in a 740‐atom CuNIR fragment. Presently we provide much more detailed structural assignment mapped to single‐residue resolution. NO2−‐binding induces both a 2 Å Cu−Cu distance increase, and pronounced frontier orbital delocalization strongly facilitating ET between the Cu regions. The conformational changes transmit from the catalytic Type II centre to the electron inlet Type I centre, via the His129‐Cys130 ligands, and via Type I–Cys130 or Type I‐His129 ending at Type II Asp92. The ET patterns are reflected in different atomic Mulliken charges in the water and nitrite CuNIR fragment.https://doi.org/10.1002/open.202400190Two-centre copper nitrite reductaseintramolecular electron transferab initio electronic stucture calculationselectrochemical STM/AFMFrontier orbitals |
| spellingShingle | Henrik Bohr Irene Shim Jens Ulstrup Xinxin Xiao Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules ChemistryOpen Two-centre copper nitrite reductase intramolecular electron transfer ab initio electronic stucture calculations electrochemical STM/AFM Frontier orbitals |
| title | Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules |
| title_full | Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules |
| title_fullStr | Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules |
| title_full_unstemmed | Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules |
| title_short | Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules |
| title_sort | protein quakes in redox metalloenzymes clues to molecular enzyme conductivity triggered by binding of small substrate molecules |
| topic | Two-centre copper nitrite reductase intramolecular electron transfer ab initio electronic stucture calculations electrochemical STM/AFM Frontier orbitals |
| url | https://doi.org/10.1002/open.202400190 |
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