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Shisler KA, Kincannon WM, Mattice JR, Larson J, Valaydon-Pillay A, Mus F, Flusche T, Kumar Nath A, Stoian SA, Raugei S, Bothner B, DuBois JL, Peters JW. Homologous acetone carboxylases select Fe(II) or Mn(II) as the catalytic cofactor. mBio 2024; 15:e0298723. [PMID: 38126751 PMCID: PMC10865871 DOI: 10.1128/mbio.02987-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
Acetone carboxylases (ACs) catalyze the metal- and ATP-dependent conversion of acetone and bicarbonate to form acetoacetate. Interestingly, two homologous ACs that have been biochemically characterized have been reported to have different metal complements, implicating different metal dependencies in catalysis. ACs from proteobacteria Xanthobacter autotrophicus and Aromatoleum aromaticum share 68% sequence identity but have been proposed to have different catalytic metals. In this work, the two ACs were expressed under the same conditions in Escherichia coli and were subjected to parallel chelation and reconstitution experiments with Mn(II) or Fe(II). Electron paramagnetic and Mössbauer spectroscopies identified signatures, respectively, of Mn(II) or Fe(II) bound at the active site. These experiments showed that the respective ACs, without the assistance of chaperones, second metal sites, or post-translational modifications facilitate correct metal incorporation, and despite the expected thermodynamic preference for Fe(II), each preferred a distinct metal. Catalysis was likewise associated uniquely with the cognate metal, though either could potentially serve the proposed Lewis acidic role. Subtle differences in the protein structure are implicated in serving as a selectivity filter for Mn(II) or Fe(II).IMPORTANCEThe Irving-Williams series refers to the predicted stabilities of transition metal complexes where the observed general stability for divalent first-row transition metal complexes increase across the row. Acetone carboxylases (ACs) use a coordinated divalent metal at their active site in the catalytic conversion of bicarbonate and acetone to form acetoacetate. Highly homologous ACs discriminate among different divalent metals at their active sites such that variations of the enzyme prefer Mn(II) over Fe(II), defying Irving-Williams-predicted behavior. Defining the determinants that promote metal discrimination within the first-row transition metals is of broad fundamental importance in understanding metal-mediated catalysis and metal catalyst design.
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Affiliation(s)
- Krista A. Shisler
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
| | - William M. Kincannon
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Jenna R. Mattice
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - James Larson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | | | - Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Tamara Flusche
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Arnab Kumar Nath
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | | | - Simone Raugei
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Jennifer L. DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - John W. Peters
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
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Van Stappen C, Dai H, Jose A, Tian S, Solomon EI, Lu Y. Primary and Secondary Coordination Sphere Effects on the Structure and Function of S-Nitrosylating Azurin. J Am Chem Soc 2023; 145:20610-20623. [PMID: 37696009 PMCID: PMC10539042 DOI: 10.1021/jacs.3c07399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2023]
Abstract
Much progress has been made in understanding the roles of the secondary coordination sphere (SCS) in tuning redox potentials of metalloproteins. In contrast, the impact of SCS on reactivity is much less understood. A primary example is how copper proteins can promote S-nitrosylation (SNO), which is one of the most important dynamic post-translational modifications, and is crucial in regulating nitric oxide storage and transportation. Specifically, the factors that instill CuII with S-nitrosylating capabilities and modulate activity are not well understood. To address this issue, we investigated the influence of the primary and secondary coordination sphere on CuII-catalyzed S-nitrosylation by developing a series of azurin variants with varying catalytic capabilities. We have employed a multidimensional approach involving electronic absorption, S and Cu K-edge XAS, EPR, and resonance Raman spectroscopies together with QM/MM computational analysis to examine the relationships between structure and molecular mechanism in this reaction. Our findings have revealed that kinetic competency is correlated with three balancing factors, namely Cu-S bond strength, Cu spin localization, and relative S(ps) vs S(pp) contributions to the ground state. Together, these results support a reaction pathway that proceeds through the attack of the Cu-S bond rather than electrophilic addition to CuII or radical attack of SCys. The insights gained from this work provide not only a deeper understanding of SNO in biology but also a basis for designing artificial and tunable SNO enzymes to regulate NO and prevent diseases due to SNO dysregulation.
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Affiliation(s)
- Casey Van Stappen
- Department of Chemistry, University of Texas at Austin, 105 E 24th St., Austin, Texas 78712, United States
| | - Huiguang Dai
- Department of Chemistry, University of Texas at Austin, 105 E 24th St., Austin, Texas 78712, United States
- Department of Chemistry, University of Urbana-Champaign, Champaign, Illinois 61801, United States
| | - Anex Jose
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
| | - Shiliang Tian
- Department of Chemistry, University of Urbana-Champaign, Champaign, Illinois 61801, United States
| | - Edward I Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, United States
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Yi Lu
- Department of Chemistry, University of Texas at Austin, 105 E 24th St., Austin, Texas 78712, United States
- Department of Chemistry, University of Urbana-Champaign, Champaign, Illinois 61801, United States
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Diep P, Kell B, Yakunin A, Hilfinger A, Mahadevan R. Quantifying metal-binding specificity of CcNikZ-II from Clostridium carboxidivorans in the presence of competing metal ions. Anal Biochem 2023; 676:115182. [PMID: 37355028 DOI: 10.1016/j.ab.2023.115182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 04/25/2023] [Accepted: 05/08/2023] [Indexed: 06/26/2023]
Abstract
Many proteins bind transition metal ions as cofactors to carry out their biological functions. Despite binding affinities for divalent transition metal ions being predominantly dictated by the Irving-Williams series for wild-type proteins, in vivo metal ion binding specificity is ensured by intracellular mechanisms that regulate free metal ion concentrations. However, a growing area of biotechnology research considers the use of metal-binding proteins in vitro to purify specific metal ions from wastewater, where specificity is dictated by the protein's metal binding affinities. A goal of metalloprotein engineering is to modulate these affinities to improve a protein's specificity towards a particular metal; however, the quantitative relationship between the affinities and the equilibrium metal-bound protein fractions depends on the underlying binding mechanisms. Here we demonstrate a high-throughput intrinsic tryptophan fluorescence quenching method to validate binding models in multi-metal solutions for CcNikZ-II, a nickel-binding protein from Clostridium carboxidivorans. Using our validated models, we quantify the relationship between binding affinity and specificity in different classes of metal-binding models for CcNikZ-II. We further illustrate the potential relevance of data-informed models to predicting engineering targets for improved specificity.
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Affiliation(s)
- Patrick Diep
- BioZone Centre for Applied Bioscience and Bioengineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada; Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA.
| | - Brayden Kell
- Department of Physics, University of Toronto, Toronto, ON, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, Canada; Department of Molecular Biosciences, Northwestern University, Evanston, IL, USA; NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, IL, USA
| | - Alexander Yakunin
- BioZone Centre for Applied Bioscience and Bioengineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada; Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Bangor, Gwynedd, UK
| | - Andreas Hilfinger
- Department of Physics, University of Toronto, Toronto, ON, Canada; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, Canada; Department of Mathematics, University of Toronto, Toronto, ON, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Radhakrishnan Mahadevan
- BioZone Centre for Applied Bioscience and Bioengineering, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada; Institute for Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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Hoffnagle AM, Tezcan FA. Atomically Accurate Design of Metalloproteins with Predefined Coordination Geometries. J Am Chem Soc 2023; 145:14208-14214. [PMID: 37352018 PMCID: PMC10439731 DOI: 10.1021/jacs.3c04047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2023]
Abstract
We report a new computational protein design method for the construction of oligomeric protein assemblies around metal centers with predefined coordination geometries. We apply this method to design two homotrimeric assemblies, Tet4 and TP1, with tetrahedral and trigonal-pyramidal tris(histidine) metal coordination geometries, respectively, and demonstrate that both assemblies form the targeted metal centers with ≤0.2 Å accuracy. Although Tet4 and TP1 are constructed from the same parent protein building block, they are distinct in terms of their overall architectures, the environment surrounding the metal centers, and their metal-based reactivities, illustrating the versatility of our approach.
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Affiliation(s)
- Alexander M. Hoffnagle
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
| | - F. Akif Tezcan
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
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Oohora K. Supramolecular assembling systems of hemoproteins using chemical modifications. J INCL PHENOM MACRO 2023. [DOI: 10.1007/s10847-023-01181-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2023]
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