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Fischer N, Tóth A, Jancsó A, Thulstrup P, Diness F. Inducing α-Helicity in Peptides by Silver Coordination to Cysteine. Chemistry 2024; 30:e202304064. [PMID: 38456607 DOI: 10.1002/chem.202304064] [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: 01/18/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 03/09/2024]
Abstract
Short peptide sequences consisting of two cysteine residues separated by three other amino acids display complete change from random coil to α-helical secondary structure in response to addition of Ag+ ions. The folded CXXXC/Ag+ complex involves formation of multinuclear Ag+ species and is stable in a wide pH range from below 3 to above 8. The complex is stable through reversed-phase HPLC separation as well as towards a physiological level of chloride ions, based on far-UV circular dichroism spectroscopy. In electrospray MS under acidic conditions a peptide dimer with four Ag+ ions bound was observed, and modelling based on potentiometric experiments supported this to be the dominating complex at neutral pH together with a peptide dimer with 3 Ag+ and one proton at lower pH. The complex was demonstrated to work as a N-terminal nucleation site for inducing α-helicity into longer peptides. This type of silver-mediated peptide assembly and folding may be of more general use for stabilizing not only peptide folding but also for controlling oligomerization even under acidic conditions.
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Affiliation(s)
- Niklas Fischer
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark
| | - Annamária Tóth
- Department of Molecular and Analytical Chemistry, University of Szeged, Dómtér 7-8, H-6720, Szeged, Hungary
| | - Attila Jancsó
- Department of Molecular and Analytical Chemistry, University of Szeged, Dómtér 7-8, H-6720, Szeged, Hungary
| | - Peter Thulstrup
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark
| | - Frederik Diness
- Department of Science and Environment, Roskilde University, Universitetsvej 1, 4000, Roskilde, Denmark
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, København Ø, Denmark
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2
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Luther P, Boyle AL. Differences in heavy metal binding to cysteine-containing coiled-coil peptides. J Pept Sci 2024; 30:e3549. [PMID: 37828738 DOI: 10.1002/psc.3549] [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: 06/14/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/14/2023]
Abstract
One third of all structurally characterised proteins contain a metal; however, the interplay between metal-binding and peptide/protein folding has yet to be fully elucidated. To better understand how metal binding affects peptide folding, a range of metals should be studied within a specific scaffold. To this end, we modified a histidine-containing coiled-coil peptide to create a cysteine-containing scaffold, named CX3C, which was designed to bind heavy metal ions. In addition, we generated a peptide named CX2C, which contains a binding site more commonly found in natural proteins. Using a combination of analytical techniques including circular dichroism (CD) spectroscopy, UV-Vis spectroscopy and size-exclusion chromatography coupled to multi-angle light scattering (SEC-MALS), we examined the differences in the metal-binding properties of the two peptides. Both peptides are largely unfolded in the apo state due to the disruption of the hydrophobic core by inclusion of the polar cysteine residues. However, this unfolding is overcome by the addition of Cd(II), Pb(II) and Hg(II), and helical assemblies are formed. Both peptides have differing affinities for these metal ions, a fact likely attributed to the differing sizes of the ions. We also show that the oligomerisation state of the peptide complexes and the coordination geometries of the metal ions differ between the two peptide scaffolds. These findings highlight that subtle changes in the primary structure of a peptide can have considerable implications for metal binding.
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Affiliation(s)
- Prianka Luther
- Macromolecular Biochemistry Group, Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
| | - Aimee L Boyle
- Macromolecular Biochemistry Group, Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
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3
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Prasad P, Hunt LA, Pall AE, Ranasinghe M, Williams AE, Stemmler TL, Demeler B, Hammer NI, Chakraborty S. Photocatalytic Hydrogen Evolution by a De Novo Designed Metalloprotein that Undergoes Ni-Mediated Oligomerization Shift. Chemistry 2023; 29:e202202902. [PMID: 36440875 PMCID: PMC10308963 DOI: 10.1002/chem.202202902] [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: 09/16/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 11/29/2022]
Abstract
De novo metalloprotein design involves the construction of proteins guided by specific repeat patterns of polar and apolar residues, which, upon self-assembly, provide a suitable environment to bind metals and produce artificial metalloenzymes. While a wide range of functionalities have been realized in de novo designed metalloproteins, the functional repertoire of such constructs towards alternative energy-relevant catalysis is currently limited. Here we show the application of de novo approach to design a functional H2 evolving protein. The design involved the assembly of an amphiphilic peptide featuring cysteines at tandem a/d sites of each helix. Intriguingly, upon NiII addition, the oligomers shift from a major trimeric assembly to a mix of dimers and trimers. The metalloprotein produced H2 photocatalytically with a bell-shape pH dependence, having a maximum activity at pH 5.5. Transient absorption spectroscopy is used to determine the timescales of electron transfer as a function of pH. Selective outer sphere mutations are made to probe how the local environment tunes activity. A preferential enhancement of activity is observed via steric modulation above the NiII site, towards the N-termini, compared to below the NiII site towards the C-termini.
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Affiliation(s)
- Pallavi Prasad
- Department of Chemistry and Biochemistry, The University of Mississippi, University, MS, 38677 (USA)
| | - Leigh Anna Hunt
- Department of Chemistry and Biochemistry, The University of Mississippi, University, MS, 38677 (USA)
| | - Ashley E. Pall
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201-2417 (USA)
| | - Maduni Ranasinghe
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401,University Dr W, Lethbridge, AB T1K 6T5 (CA)
| | - Ashley E. Williams
- Department of Chemistry and Biochemistry, The University of Mississippi, University, MS, 38677 (USA)
| | - Timothy L. Stemmler
- Department of Pharmaceutical Sciences, Wayne State University, 259 Mack Avenue, Detroit, MI, 48201-2417 (USA)
| | - Borries Demeler
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401,University Dr W, Lethbridge, AB T1K 6T5 (CA)
| | - Nathan I. Hammer
- Department of Chemistry and Biochemistry, The University of Mississippi, University, MS, 38677 (USA)
| | - Saumen Chakraborty
- Department of Chemistry and Biochemistry, The University of Mississippi, University, MS, 38677 (USA)
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4
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Łuczkowski M, Padjasek M, Ba Tran J, Hemmingsen L, Kerber O, Habjanič J, Freisinger E, Krężel A. An Extremely Stable Interprotein Tetrahedral Hg(Cys) 4 Core Forms in the Zinc Hook Domain of Rad50 Protein at Physiological pH. Chemistry 2022; 28:e202202738. [PMID: 36222310 PMCID: PMC9828754 DOI: 10.1002/chem.202202738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Indexed: 11/09/2022]
Abstract
In nature, thiolate-based systems are the primary targets of divalent mercury (HgII ) toxicity. The formation of Hg(Cys)x cores in catalytic and structural protein centers mediates mercury's toxic effects and ultimately leads to cellular damage. Multiple studies have revealed distinct HgII -thiolate coordination preferences, among which linear HgII complexes are the most commonly observed in solution at physiological pH. Trigonal or tetrahedral geometries are formed at basic pH or in tight intraprotein Cys-rich metal sites. So far, no interprotein tetrahedral HgII complex formed at neutral pH has been reported. Rad50 protein is a part of the multiprotein MRN complex, a major player in DNA damage-repair processes. Its central region consists of a conserved CXXC motif that enables dimerization of two Rad50 molecules by coordinating ZnII . Dimerized motifs form a unique interprotein zinc hook domain (Hk) that is critical for the biological activity of the MRN. Using a series of length-differentiated peptide models of the Pyrococcus furiosus zinc hook domain, we investigated its interaction with HgII . Using UV-Vis, CD, PAC, and 199 Hg NMR spectroscopies as well as anisotropy decay, we discovered that all Rad50 fragments preferentially form homodimeric Hg(Hk)2 species with a distorted tetrahedral HgS4 coordination environment at physiological pH; this is the first example of an interprotein mercury site displaying tetrahedral geometry in solution. At higher HgII content, monomeric HgHk complexes with linear geometry are formed. The Hg(Cys)4 core of Rad50 is extremely stable and does not compete with cyanides, NAC, or DTT. Applying ITC, we found that the stability constant of the Rad50 Hg(Hk)2 complex is approximately three orders of magnitude higher than those of the strongest HgII complexes known to date.
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Affiliation(s)
- Marek Łuczkowski
- Department of Chemical BiologyFaculty of BiotechnologyUniversity of WrocławJoliot-Curie 14a50-383WrocławPoland
| | - Michał Padjasek
- Department of Chemical BiologyFaculty of BiotechnologyUniversity of WrocławJoliot-Curie 14a50-383WrocławPoland
| | - Józef Ba Tran
- Department of Chemical BiologyFaculty of BiotechnologyUniversity of WrocławJoliot-Curie 14a50-383WrocławPoland
| | - Lars Hemmingsen
- Department of ChemistryUniversity of CopenhagenUniversitetsparken 52100København ØDenmark
| | - Olga Kerber
- Department of Chemical BiologyFaculty of BiotechnologyUniversity of WrocławJoliot-Curie 14a50-383WrocławPoland
| | - Jelena Habjanič
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 1908057ZürichSwitzerland
| | - Eva Freisinger
- Department of ChemistryUniversity of ZurichWinterthurerstrasse 1908057ZürichSwitzerland
| | - Artur Krężel
- Department of Chemical BiologyFaculty of BiotechnologyUniversity of WrocławJoliot-Curie 14a50-383WrocławPoland
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Abstract
While 199Hg NMR is a well-established tool for elucidating details of coordination chemistry in biochemical and inorganic complexes, historically the technique has been associated with the use of an extremely toxic chemical, dimethylmercury [Me2Hg or (CH3)2Hg], as a reference standard. In the 25 years since an accidental exposure to Me2Hg led to the tragic death of Dr. Karen Wetterhahn, the community has learned a great deal about the insidious neurotoxicity of this compound as well as more appropriate ways to avoid exposure. Here, we track the general shift toward the use of alternative mercury reference standards and away from Me2Hg.
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Affiliation(s)
- David Z. Zee
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Christopher P. Singer
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Thomas V. O’Halloran
- The Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, United States
- The Elemental Health Institute, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States
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Efficient Removal of Hg(II) from Water under Mildly Acidic Conditions with Hierarchical SiO2 Monoliths Functionalized with –SH Groups. MATERIALS 2022; 15:ma15041580. [PMID: 35208122 PMCID: PMC8874887 DOI: 10.3390/ma15041580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/16/2022] [Accepted: 02/16/2022] [Indexed: 11/21/2022]
Abstract
In this work, novel adsorbents based on 3D hierarchical silica monoliths functionalized with thiol groups were used for the removal of Hg(II) ions from an acidic aqueous solution (pH 3.5). Silica monoliths were synthesized by using two different pluronic triblock polymers (P123 and F127) to study the effect of porous structure on their sorption capacity. Before and after functionalization by grafting with 3-mercaptopropyltrimethoxysilane (MPTMS), the monoliths were characterized by several techniques, and their Hg(II) removal potential was evaluated in batch experiments at 28 °C and pH 3.5, using different initial concentrations of Hg(II) ions in water (200–500 mg L−1). The thiol groups of the monoliths calcined at 550 °C showed thermal stability up to 300 °C (from TG/DTG). The functionalized monolith synthesized with P123 polymer and polyethylene glycol showed favorable hierarchical macro-mesopores for Hg(II) adsorption. M(P123)–SH exhibited 97% removal of Hg(II) at concentration 200 mg L−1. Its maximum adsorption capacity (12.2 mmol g−1) was two times higher than that of M(F127)–SH, demonstrating that the 3D hierarchical macro-mesoporosity allowing accessibility of Hg(II) to thiol groups favors the physical and chemical adsorption of Hg(II) under slightly acidic conditions.
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Malayam Parambath S, Williams AE, Hunt LA, Selvan D, Hammer NI, Chakraborty S. A De Novo-Designed Artificial Metallopeptide Hydrogenase: Insights into Photochemical Processes and the Role of Protonated Cys. CHEMSUSCHEM 2021; 14:2237-2246. [PMID: 33787007 PMCID: PMC8569915 DOI: 10.1002/cssc.202100122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/29/2021] [Indexed: 06/01/2023]
Abstract
Hydrogenase enzymes produce H2 gas, which can be a potential source of alternative energy. Inspired by the [NiFe] hydrogenases, we report the construction of a de novo-designed artificial hydrogenase (ArH). The ArH is a dimeric coiled coil where two cysteine (Cys) residues are introduced at tandem a/d positions of a heptad to create a tetrathiolato Ni binding site. Spectroscopic studies show that Ni binding significantly stabilizes the peptide producing electronic transitions characteristic of Ni-thiolate proteins. The ArH produces H2 photocatalytically, demonstrating a bell-shaped pH-dependence on activity. Fluorescence lifetimes and transient absorption spectroscopic studies are undertaken to elucidate the nature of pH-dependence, and to monitor the reaction kinetics of the photochemical processes. pH titrations are employed to determine the role of protonated Cys on reactivity. Through combining these results, a fine balance is found between solution acidity and the electron transfer steps. This balance is critical to maximize the production of NiI -peptide and protonation of the NiII -H- intermediate (Ni-R) by a Cys (pKa ≈6.4) to produce H2 .
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Affiliation(s)
- Sreya Malayam Parambath
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Ashley E Williams
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Leigh Anna Hunt
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Dhanashree Selvan
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Nathan I Hammer
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Saumen Chakraborty
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
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8
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Evaluating the involvement of tryptophan on thiolated peptide-mercury(II) complexes: Cation-pi interactions. Inorganica Chim Acta 2020. [DOI: 10.1016/j.ica.2020.119552] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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9
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Szekeres LI, Bálint S, Galbács G, Kálomista I, Kiss T, Larsen FH, Hemmingsen L, Jancsó A. Hg 2+ and Cd 2+ binding of a bioinspired hexapeptide with two cysteine units constructed as a minimalistic metal ion sensing fluorescent probe. Dalton Trans 2019; 48:8327-8339. [PMID: 31111849 DOI: 10.1039/c9dt01141b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hg2+ and Cd2+ complexation of a short hexapeptide, Ac-DCSSCY-NH2 (DY), was studied by pH-potentiometry, UV and NMR spectroscopy and fluorimetry in aqueous solutions and the Hg2+-binding ability of the ligand was also described in an immobilized form, where the peptides were anchored to a hydrophilic resin. Hg2+ was demonstrated to form a 1 : 1 complex with the ligand even at pH = 2.0 while Cd2+ coordination by the peptide takes place only above pH ∼ 3.5. Both metal ions form bis-ligand complexes by the coordination of four Cys-thiolates at ligand excess above pH ∼ 5.5 (Cd2+) and 7.0 (Hg2+). Fluorescence studies demonstrated a Hg2+ induced concentration-dependent quenching of the Tyr fluorescence until a 1 : 1 Hg2+ : DY ratio. The fluorescence emission intensity decreases linearly with the increasing Hg2+ concentration in a range of over two orders of magnitude. The fact that this occurs even in the presence of 1.0 eq. of Cd2+ per ligand reflects a complete displacement of the latter metal ion by Hg2+ from its peptide-bound form. The immobilized peptide was also shown to bind Hg2+ very efficiently even from samples at pH = 2.0. However, the existence of lower affinity binding sites was also demonstrated by binding of more than 1.0 eq. of Hg2+ per immobilized DY molecule under Hg2+-excess conditions. Experiments performed with a mixture of four metal ions, Hg2+, Cd2+, Zn2+ and Ni2+, indicate that this molecular probe may potentially be used in Hg2+-sensing systems under acidic conditions for the measurement of μM range concentrations.
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Affiliation(s)
- Levente I Szekeres
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
| | - Sára Bálint
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
| | - Gábor Galbács
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
| | - Ildikó Kálomista
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
| | - Tamás Kiss
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
| | - Flemming H Larsen
- Department of Food Science, University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C, Denmark
| | - Lars Hemmingsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Attila Jancsó
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged, H-6720, Hungary.
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Domínguez-Calva JA, Pérez-Vázquez ML, Serebryany E, King JA, Quintanar L. Mercury-induced aggregation of human lens γ-crystallins reveals a potential role in cataract disease. J Biol Inorg Chem 2018; 23:1105-1118. [DOI: 10.1007/s00775-018-1607-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 08/22/2018] [Indexed: 01/17/2023]
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11
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Sénèque O, Rousselot-Pailley P, Pujol A, Boturyn D, Crouzy S, Proux O, Manceau A, Lebrun C, Delangle P. Mercury Trithiolate Binding (HgS 3) to a de Novo Designed Cyclic Decapeptide with Three Preoriented Cysteine Side Chains. Inorg Chem 2018; 57:2705-2713. [PMID: 29443519 DOI: 10.1021/acs.inorgchem.7b03103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mercury(II) is an unphysiological soft ion with high binding affinity for thiolate ligands. Its toxicity lies in the interactions with low molecular weight thiols including glutathione and cysteine-containing proteins that disrupt the thiol balance and alter vital functions. However, mercury can also be detoxified via interactions with Hg(II)-responsive regulatory proteins such as MerR, which coordinates Hg(II) with three cysteine residues in a trigonal planar fashion (HgS3 coordination). The model cyclodecapeptide P3C, c(GCTCSGCSRP) was designed to promote Hg(II) chelation in a HgS3 coordination environment through the parallel orientation of three cysteine side chains. The binding motif is derived from the dicysteine P2C cyclodecapeptide validated previously as a model for d10 metal transporters containing the binding sequence CxxC. The formation of the mononuclear HgP3C complex with a HgS3 coordination is demonstrated using electrospray ionization mass spectrometry, UV absorption, and 199Hg NMR. Hg LIII-edge extended X-ray absorption fine structure (EXAFS) spectroscopy indicates that the Hg(II) coordination environment is T-shaped with two short Hg-S distances at 2.45 Å and one longer distance at 2.60 Å. The solution structure of the HgP3C complex was refined based on 1H-1H NMR constraints and EXAFS results. The cyclic peptide scaffold has a rectangular shape with the three binding cysteine side chains pointing toward Hg(II). The HgP3CH complex has a p Ka of 4.3, indicating that the HgS3 coordination mode is stable over a large range of pH. This low p Ka value suggests that the preorientation of the three cysteine groups is particularly well-achieved for Hg(II) trithiolate coordination in P3C.
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Affiliation(s)
- Olivier Sénèque
- INAC-SyMMES , Univ. Grenoble Alpes, CEA, CNRS , 38000 Grenoble , France.,Univ. Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249) , 38000 Grenoble , France
| | | | - Anaïs Pujol
- INAC-SyMMES , Univ. Grenoble Alpes, CEA, CNRS , 38000 Grenoble , France
| | - Didier Boturyn
- DCM UMR 5250, Université Grenoble Alpes-CNRS , 38041 Grenoble cedex 9 , France
| | - Serge Crouzy
- Univ. Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249) , 38000 Grenoble , France
| | - Olivier Proux
- BM30B/FAME beamline , ESRF , 38043 Grenoble cedex 9 , France
| | - Alain Manceau
- ISTerre , Univ. Grenoble Alpes, CNRS , CS 40700 , 38058 Grenoble , France
| | - Colette Lebrun
- INAC-SyMMES , Univ. Grenoble Alpes, CEA, CNRS , 38000 Grenoble , France
| | - Pascale Delangle
- INAC-SyMMES , Univ. Grenoble Alpes, CEA, CNRS , 38000 Grenoble , France
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12
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Mesterházy E, Lebrun C, Crouzy S, Jancsó A, Delangle P. Short oligopeptides with three cysteine residues as models of sulphur-rich Cu(i)- and Hg(ii)-binding sites in proteins. Metallomics 2018; 10:1232-1244. [DOI: 10.1039/c8mt00113h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peptides mimicking sulphur-rich fragments found in metallothioneins display unexpectedly different behaviours with the two metal ions Hg(ii) and Cu(i).
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Affiliation(s)
- Edit Mesterházy
- INAC/SYMMES/Université Grenoble Alpes
- CEA
- CNRS
- 38000 Grenoble
- France
| | - Colette Lebrun
- Department of Inorganic and Analytical Chemistry
- University of Szeged
- Szeged H-6720
- Hungary
| | - Serge Crouzy
- BIG/LCBM/Université Grenoble Alpes
- CEA
- CNRS
- (UMR 5249)
- 38000 Grenoble
| | - Attila Jancsó
- Department of Inorganic and Analytical Chemistry
- University of Szeged
- Szeged H-6720
- Hungary
| | - Pascale Delangle
- INAC/SYMMES/Université Grenoble Alpes
- CEA
- CNRS
- 38000 Grenoble
- France
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13
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Application of Heteronuclear NMR Spectroscopy to Bioinorganic and Medicinal Chemistry ☆. REFERENCE MODULE IN CHEMISTRY, MOLECULAR SCIENCES AND CHEMICAL ENGINEERING 2018. [PMCID: PMC7157447 DOI: 10.1016/b978-0-12-409547-2.10947-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Ruckthong L, Stuckey JA, Pecoraro VL. Methods for Solving Highly Symmetric De Novo Designed Metalloproteins: Crystallographic Examination of a Novel Three-Stranded Coiled-Coil Structure Containing d-Amino Acids. Methods Enzymol 2016; 580:135-48. [PMID: 27586331 DOI: 10.1016/bs.mie.2016.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The core objective of de novo metalloprotein design is to define metal-protein relationships that control the structure and function of metal centers by using simplified proteins. An essential requirement to achieve this goal is to obtain high resolution structural data using either NMR or crystallographic studies in order to evaluate successful design. X-ray crystal structures have proven that a four heptad repeat scaffold contained in the three-stranded coiled coil (3SCC), called CoilSer (CS), provides an excellent motif for modeling a three Cys binding environment capable of chelating metals into geometries that resemble heavy metal sites in metalloregulatory systems. However, new generations of more complicated designs that feature, for example, a d-amino acid or multiple metal ligand sites in the helical sequence require a more stable construct. In doing so, an extra heptad was introduced into the original CS sequence, yielding a GRAND-CoilSer (GRAND-CS) to retain the 3SCC folding. An apo-(GRAND-CSL12DLL16C)3 crystal structure, designed for Cd(II)S3 complexation, proved to be a well-folded parallel 3SCC. Because this structure is novel, protocols for crystallization, structural determination, and refinements of the apo-(GRAND-CSL12DLL16C)3 are described. This report should be generally useful for future crystallographic studies of related coiled-coil designs.
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Affiliation(s)
- L Ruckthong
- Department of Chemistry, University of Michigan, Ann Arbor, MI, United States
| | - J A Stuckey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, United States
| | - V L Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, MI, United States.
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15
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Warner T, Jalilehvand F. Formation of Hg(II) Tetrathiolate Complexes with Cysteine at Neutral pH. CAN J CHEM 2016; 94:373-379. [PMID: 27064521 DOI: 10.1139/cjc-2015-0375] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mercury(II) ions precipitate from aqueous cysteine (H2Cys) solutions containing H2Cys/Hg(II) mole ratio ≥ 2.0 as Hg(S-HCys)2. In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg(S,N-Cys)2]2- complex dominating. With excess cysteine (H2Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg(S-Cys)4]6- complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which CHg(II) varied between 8 - 9 mM and 80 - 100 mM, respectively, with H2Cys/Hg(II) mole ratios from 4 to ~20. The solutions were prepared in the pH range 7.1 - 8.8, at the pH at which the initial Hg(S-HCys)2 precipitate dissolved. The variations in the Hg(II) speciation were followed by 199Hg NMR, X-ray absorption and Raman spectroscopic techniques. Our results show that in the dilute solutions (CHg(II) = 8 - 9 mM), mixtures of di-, tri- (major) and tetrathiolate complexes exist at moderate cysteine excess (CH2Cys ~ 0.16 M) at pH 7.1. In the more concentrated solutions (CHg(II) = 80 - 100 mM) with high cysteine excess (CH2Cys > 0.9 M), tetrathiolate [Hg(S-cysteinate)4] m-6 (m = 0 - 4) complexes dominate in the pH range 7.3 - 7.8, with lower charge than for the [Hg(S-Cys)4]6- complex due to protonation of some (m) of the amino groups of the coordinated cysteine ligands. The results of this investigation could provide a key to the mechanism of biosorption and accumulation of Hg(II) ions in biological / environmental systems.
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Affiliation(s)
- Thomas Warner
- Department of Chemistry, University of Calgary, 2500 University Drive, Calgary, Alberta T2N 1N4
| | - Farideh Jalilehvand
- Department of Chemistry, University of Calgary, 2500 University Drive, Calgary, Alberta T2N 1N4
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16
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Jullien AS, Gateau C, Lebrun C, Delangle P. Mercury Complexes with Tripodal Pseudopeptides Derived fromD-Penicillamine Favour a HgS3Coordination. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500421] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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17
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Szunyogh D, Gyurcsik B, Larsen FH, Stachura M, Thulstrup PW, Hemmingsen L, Jancsó A. Zn(II) and Hg(II) binding to a designed peptide that accommodates different coordination geometries. Dalton Trans 2015; 44:12576-88. [PMID: 26040991 DOI: 10.1039/c5dt00945f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Designed metal ion binding peptides offer a variety of applications in both basic science as model systems of more complex metalloproteins, and in biotechnology, e.g. in bioremediation of toxic metal ions, biomining or as artificial enzymes. In this work a peptide (HS: Ac-SCHGDQGSDCSI-NH2) has been specifically designed for binding of both Zn(II) and Hg(II), i.e. metal ions with different preferences in terms of coordination number, coordination geometry, and to some extent ligand composition. It is demonstrated that HS accommodates both metal ions, and the first coordination sphere, metal ion exchange between peptides, and speciation are characterized as a function of pH using UV-absorption-, synchrotron radiation CD-, (1)H-NMR-, and PAC-spectroscopy as well as potentiometry. Hg(II) binds to the peptide with very high affinity in a {HgS2} coordination geometry, bringing together the two cysteinates close to each end of the peptide in a loop structure. Despite the high affinity, Hg(II) is kinetically labile, exchanging between peptides on the subsecond timescale, as indicated by line broadening in (1)H-NMR. The Zn(II)-HS system displays more complex speciation, involving monomeric species with coordinating cysteinates, histidine, and a solvent water molecule, as well as HS-Zn(II)-HS complexes. In summary, the HS peptide displays conformational flexibility, contains many typical metal ion binding groups, and is able to accommodate metal ions with different structural and ligand preferences with high affinity. As such, the HS peptide may be a scaffold offering binding of a variety of metal ions, and potentially serve for metal ion sequestration in biotechnological applications.
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Affiliation(s)
- Dániel Szunyogh
- MTA-SZTE Bioinorganic Chemistry Research Group, Dóm tér 7, Szeged, H-6720, Hungary
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18
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Plegaria JS, Pecoraro VL. Sculpting Metal-binding Environments in De Novo Designed Three-helix Bundles. Isr J Chem 2015; 55:85-95. [PMID: 29353917 PMCID: PMC5771423 DOI: 10.1002/ijch.201400146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
De novo protein design is a biologically relevant approach used to study the active centers of native metalloproteins. In this review, we will first discuss the design process in achieving α3D, a de novo designed three-helix bundle peptide with a well-defined fold. We will then cover our recent work in functionalizing the α3D framework by incorporating a tris(cysteine) and tris(histidine) motif. Our first design contains the thiol-rich sites found in metalloregulatory proteins that control the levels of toxic metal ions (Hg, Cd, and Pb). The latter design recapitulates the catalytic site and activity of a natural metalloenzyme carbonic anhydrase. The review will conclude with future design goals aimed at introducing an asymmetric metal-binding site in the α3D framework.
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Affiliation(s)
- Jefferson S Plegaria
- 930 North University Ave, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 (USA)
| | - Vincent L Pecoraro
- 930 North University Ave, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 (USA)
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19
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Zastrow M, Pecoraro VL. Designing hydrolytic zinc metalloenzymes. Biochemistry 2014; 53:957-78. [PMID: 24506795 PMCID: PMC3985962 DOI: 10.1021/bi4016617] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 01/23/2014] [Indexed: 12/15/2022]
Abstract
Zinc is an essential element required for the function of more than 300 enzymes spanning all classes. Despite years of dedicated study, questions regarding the connections between primary and secondary metal ligands and protein structure and function remain unanswered, despite numerous mechanistic, structural, biochemical, and synthetic model studies. Protein design is a powerful strategy for reproducing native metal sites that may be applied to answering some of these questions and subsequently generating novel zinc enzymes. From examination of the earliest design studies introducing simple Zn(II)-binding sites into de novo and natural protein scaffolds to current studies involving the preparation of efficient hydrolytic zinc sites, it is increasingly likely that protein design will achieve reaction rates previously thought possible only for native enzymes. This Current Topic will review the design and redesign of Zn(II)-binding sites in de novo-designed proteins and native protein scaffolds toward the preparation of catalytic hydrolytic sites. After discussing the preparation of Zn(II)-binding sites in various scaffolds, we will describe relevant examples for reengineering existing zinc sites to generate new or altered catalytic activities. Then, we will describe our work on the preparation of a de novo-designed hydrolytic zinc site in detail and present comparisons to related designed zinc sites. Collectively, these studies demonstrate the significant progress being made toward building zinc metalloenzymes from the bottom up.
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Affiliation(s)
| | - Vincent L. Pecoraro
- Department of Chemistry, University
of Michigan, Ann Arbor, Michigan 48109, United
States
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20
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Zastrow ML, Pecoraro VL. Designing functional metalloproteins: from structural to catalytic metal sites. Coord Chem Rev 2013; 257:2565-2588. [PMID: 23997273 PMCID: PMC3756834 DOI: 10.1016/j.ccr.2013.02.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Metalloenzymes efficiently catalyze some of the most important and difficult reactions in nature. For many years, coordination chemists have effectively used small molecule models to understand these systems. More recently, protein design has been shown to be an effective approach for mimicking metal coordination environments. Since the first designed proteins were reported, much success has been seen for incorporating metal sites into proteins and attaining the desired coordination environment but until recently, this has been with a lack of significant catalytic activity. Now there are examples of designed metalloproteins that, although not yet reaching the activity of native enzymes, are considerably closer. In this review, we highlight work leading up to the design of a small metalloprotein containing two metal sites, one for structural stability (HgS3) and the other a separate catalytic zinc site to mimic carbonic anhydrase activity (ZnN3O). The first section will describe previous studies that allowed for a high affinity thiolate site that binds heavy metals in a way that stabilizes three-stranded coiled coils. The second section will examine ways of preparing histidine rich environments that lead to metal based hydrolytic catalysts. We will also discuss other recent examples of the design of structural metal sites and functional metalloenzymes. Our work demonstrates that attaining the proper first coordination geometry of a metal site can lead to a significant fraction of catalytic activity, apparently independent of the type of secondary structure of the surrounding protein environment. We are now in a position to begin to meet the challenge of building a metalloenzyme systematically from the bottom-up by engineering and analyzing interactions directly around the metal site and beyond.
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Affiliation(s)
- Melissa L. Zastrow
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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21
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Jancsó A, Gyurcsik B, Mesterházy E, Berkecz R. Competition of zinc(II) with cadmium(II) or mercury(II) in binding to a 12-mer peptide. J Inorg Biochem 2013; 126:96-103. [PMID: 23796441 DOI: 10.1016/j.jinorgbio.2013.05.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/29/2013] [Accepted: 05/29/2013] [Indexed: 11/15/2022]
Abstract
Speciation of the complexes of zinc(II) with a dodecapeptide (Ac-SCPGDQGSDCSI-NH2), inspired by the metal binding domain of MerR metalloregulatory proteins, have been studied by pH-potentiometric titrations, UV, SRCD (synchrotron radiation circular dichroism) and (1)H NMR experiments. (MerR is a family of transcriptional regulators the archetype of which is the Hg(2+)-responsive transcriptional repressor-activator MerR protein.) The aim of the ligand-design was to retain the advantageous metal binding features of MerR proteins in a model peptide for the efficient capture of toxic metal ions. The peptide binds zinc(II) via two deprotonated Cys-thiol groups and one of the Asp-carboxylates in the ZnL parent complex, possessing a remarkably high stability (logK=9.93). In spite of the relatively long peptide loop, bis-complexes are also formed with the metal ion under basic conditions. In a competition with cadmium(II) or mercury(II), zinc(II) cannot prevent the binding of toxic metal ions by the thiolate donor groups of the ligand. Around neutral pH one equivalent of mercury(II) was shown to fully replace zinc(II) from the ZnL species. Partial replacement of zinc(II) from the peptide by one equivalent of cadmium(II), relative to zinc(II) and the ligand, is also presumable, nevertheless, spectroscopic data may suggest the formation of mixed metal ion complexes, as well. Based on the obtained results the investigated dodecapeptide can be a promising candidate for capturing toxic metal ions in practical applications.
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Affiliation(s)
- Attila Jancsó
- Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, Szeged H-6720, Hungary.
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22
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Łuczkowski M, Zeider BA, Hinz AVH, Stachura M, Chakraborty S, Hemmingsen L, Huffman DL, Pecoraro VL. Probing the coordination environment of the human copper chaperone HAH1: characterization of Hg(II)-bridged homodimeric species in solution. Chemistry 2013; 19:9042-9. [PMID: 23677531 DOI: 10.1002/chem.201204184] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 04/16/2013] [Indexed: 01/23/2023]
Abstract
Although metal ion homeostasis in cells is often mediated through metallochaperones, there are opportunities for toxic metals to be sequestered through the existing transport apparatus. Proper trafficking of Cu(I) in human cells is partially achieved through complexation by HAH1, the human metallochaperone responsible for copper delivery to the Wilson and Menkes ATPase located in the trans-Golgi apparatus. In addition to binding copper, HAH1 strongly complexes Hg(II), with the X-ray structure of this complex previously described. It is important to clarify the solution behavior of these systems and, therefore, the binding of Hg(II) to HAH1 was probed over the pH range 7.5 to 9.4 using (199)Hg NMR, (199m)Hg PAC and UV-visible spectroscopies. The metal-dependent protein association over this pH range was examined using analytical gel-filtration. It can be concluded that at pH 7.5, Hg(II) is bound to a monomeric HAH1 as a two coordinate, linear complex (HgS2), like the Hg(II)-Atx1 X-ray structure (PDB ID: 1CC8). At pH 9.4, Hg(II) promotes HAH1 association, leading to formation of HgS3 and HgS4 complexes, which are in exchange on the μs-ns time scale. Thus, structures that may represent central intermediates in the process of metal ion transfer, as well as their exchange kinetics have been characterized.
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Affiliation(s)
- Marek Łuczkowski
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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23
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Abstract
This chapter describes an approach using designed proteins to understand the structure, spectroscopy, and dynamics of proteins that bind Cd(II). We will show that three-stranded coiled coils (3SCCs) based on the parent peptides TRI (Ac-G(LKALEEK)(4)G-NH(2)) or GRAND (Ac-G(LKALEEK)(5)G-NH(2)) have been essential for understanding how Cd(II) binds to thiolate-rich environments in proteins. Examples are given correlating physical properties such as the binding constants or deprotonation constants relating to structure. We present a scale that relates (113)Cd NMR chemical shifts to structures extracted from (111m)Cd PAC experiments. In addition, we describe motional processes that help transport from the helical interface of proteins into the hydrophobic interior of helical bundles. These studies help clarify the chemistry of Cd(II) in relation to metal-regulated gene expression and detoxification.
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Pires S, Habjanič J, Sezer M, Soares CM, Hemmingsen L, Iranzo O. Design of a Peptidic Turn with High Affinity for HgII. Inorg Chem 2012; 51:11339-48. [DOI: 10.1021/ic3008014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Sara Pires
- Instituto de Tecnologia
Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157
Oeiras, Portugal
| | - Jelena Habjanič
- Instituto de Tecnologia
Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157
Oeiras, Portugal
| | - Murat Sezer
- Instituto de Tecnologia
Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157
Oeiras, Portugal
| | - Cláudio M. Soares
- Instituto de Tecnologia
Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157
Oeiras, Portugal
| | - Lars Hemmingsen
- Department of Chemistry, University of Copenhagen, Universitetsparken
5, 2100 København Ø, Denmark
| | - Olga Iranzo
- Instituto de Tecnologia
Química e Biológica, Universidade Nova de Lisboa, Avenida da República, 2780-157
Oeiras, Portugal
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25
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Pujol AM, Lebrun C, Gateau C, Manceau A, Delangle P. Mercury-Sequestering Pseudopeptides with a Tris(cysteine) Environment in Water. Eur J Inorg Chem 2012. [DOI: 10.1002/ejic.201200484] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Jancsó A, Szunyogh D, Larsen FH, Thulstrup PW, Christensen NJ, Gyurcsik B, Hemmingsen L. Towards the role of metal ions in the structural variability of proteins: CdII speciation of a metal ion binding loop motif. Metallomics 2011; 3:1331-9. [PMID: 22041892 DOI: 10.1039/c1mt00138h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A de novo designed dodecapeptide (HS), inspired by the metal binding loops of metal-responsive transcriptional activators, was synthesized. The aim was to create a model system for structurally promiscuous and intrinsically unstructured proteins, and explore the effect of metal ions on their structure and dynamics. The interaction with Cd(II) was investigated by UV, synchrotron radiation CD, (1)H NMR, and perturbed angular correlation (PAC) of γ-rays spectroscopy, pH-potentiometry, and molecular modelling. The peptide mainly displays characteristics of random coil in the CD spectra, and the molecular dynamics simulations demonstrate that it is unstructured with transient and varying helical content. The spectroscopic studies revealed the formation of loop structures with the coordination of the two Cys-thiolates close to each end of the HS peptide, in the presence of one equivalent of Cd(II) per ligand. The imidazole moiety from histidine is also bound to Cd(II) at neutral pH and above. In the presence of 0.5 equivalent of Cd(II) per HS metal bridged structures with e.g. CdS(2)N(2) and possibly CdS(4) coordination geometries are formed above pH ~6. In an equilibrium of several co-existing species the peptide is exchanging between a number of structures also in its metal ion bound state(s), as indicated by NMR and PAC data.
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Affiliation(s)
- Attila Jancsó
- Department of Inorganic and Analytical Chemistry, University of Szeged, Szeged, Hungary.
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27
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Arcisauskaite V, Melo JI, Hemmingsen L, Sauer SPA. Nuclear magnetic resonance shielding constants and chemical shifts in linear 199Hg compounds: A comparison of three relativistic computational methods. J Chem Phys 2011; 135:044306. [DOI: 10.1063/1.3608153] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Chakraborty S, Kravitz JY, Thulstrup PW, Hemmingsen L, DeGrado WF, Pecoraro VL. Design of a three-helix bundle capable of binding heavy metals in a triscysteine environment. Angew Chem Int Ed Engl 2011; 50:2049-53. [PMID: 21344549 PMCID: PMC3058785 DOI: 10.1002/anie.201006413] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Indexed: 11/06/2022]
Affiliation(s)
- Saumen Chakraborty
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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29
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Chakraborty S, Yudenfreund Kravitz J, Thulstrup PW, Hemmingsen L, DeGrado WF, Pecoraro VL. Design of a Three-Helix Bundle Capable of Binding Heavy Metals in a Triscysteine Environment. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201006413] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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30
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Iranzo O, Chakraborty S, Hemmingsen L, Pecoraro VL. Controlling and fine tuning the physical properties of two identical metal coordination sites in de novo designed three stranded coiled coil peptides. J Am Chem Soc 2011; 133:239-51. [PMID: 21162521 PMCID: PMC3149768 DOI: 10.1021/ja104433n] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein we report how de novo designed peptides can be used to investigate whether the position of a metal site along a linear sequence that folds into a three-stranded α-helical coiled coil defines the physical properties of Cd(II) ions in either CdS(3) or CdS(3)O (O-being an exogenous water molecule) coordination environments. Peptides are presented that bind Cd(II) into two identical coordination sites that are located at different topological positions at the interior of these constructs. The peptide GRANDL16PenL19IL23PenL26I binds two Cd(II) as trigonal planar 3-coordinate CdS(3) structures whereas GRANDL12AL16CL26AL30C sequesters two Cd(II) as pseudotetrahedral 4-coordinate CdS(3)O structures. We demonstrate how for the first peptide, having a more rigid structure, the location of the identical binding sites along the linear sequence does not affect the physical properties of the two bound Cd(II). However, the sites are not completely independent as Cd(II) bound to one of the sites ((113)Cd NMR chemical shift of 681 ppm) is perturbed by the metalation state (apo or [Cd(pep)(Hpep)(2)](+) or [Cd(pep)(3)](-)) of the second center ((113)Cd NMR chemical shift of 686 ppm). GRANDL12AL16CL26AL30C shows a completely different behavior. The physical properties of the two bound Cd(II) ions indeed depend on the position of the metal center, having pK(a2) values for the equilibrium [Cd(pep)(Hpep)(2)](+) → [Cd(pep)(3)](-) + 2H(+) (corresponding to deprotonation and coordination of cysteine thiols) that range from 9.9 to 13.9. In addition, the L26AL30C site shows dynamic behavior, which is not observed for the L12AL16C site. These results indicate that for these systems one cannot simply assign a "4-coordinate structure" and assume certain physical properties for that site since important factors such as packing of the adjacent Leu, size of the intended cavity (endo vs exo) and location of the metal site play crucial roles in determining the final properties of the bound Cd(II).
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Affiliation(s)
- Olga Iranzo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA, Fax: (+1) 734-936-7628,
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Avenida República, EAN, 2785-572 Oeiras, Portugal
| | - Saumen Chakraborty
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA, Fax: (+1) 734-936-7628,
| | - Lars Hemmingsen
- Department of Basic Sciences and Environment, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
| | - Vincent L. Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA, Fax: (+1) 734-936-7628,
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31
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Chakraborty S, Touw DS, Peacock AFA, Stuckey J, Pecoraro VL. Structural comparisons of apo- and metalated three-stranded coiled coils clarify metal binding determinants in thiolate containing designed peptides. J Am Chem Soc 2010; 132:13240-50. [PMID: 20825181 PMCID: PMC3004433 DOI: 10.1021/ja101812c] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Over the past two decades, designed metallopeptides have held the promise for understanding a variety of fundamental questions in metallobiochemistry; however, these dreams have not yet been realized because of a lack of structural data to elaborate the protein scaffolds before metal complexation and the resultant metalated structures which ultimately exist. This is because there are few reports of structural characterization of such systems either in their metalated or nonmetalated forms and no examples where an apo structure and the corresponding metalated peptide assembly have both been defined by X-ray crystallography. Herein we present X-ray structures of two de novo designed parallel three-stranded coiled coils (designed using the heptad repeat (a → g)) CSL9C (CS = Coil Ser) and CSL19C in their nonmetalated forms, determined to 1.36 and 2.15 A resolutions, respectively. Leucines from either position 9 (a site) or 19 (d site) are replaced by cysteine to generate the constructs CSL9C and CSL19C, respectively, yielding thiol-rich pockets at the hydrophobic interior of these peptides, suitable to bind heavy metals such as As(III), Hg(II), Cd(II), and Pb(II). We use these structures to understand the inherent structural differences between a and d sites to clarify the basis of the observed differential spectroscopic behavior of metal binding in these types of peptides. Cys side chains of (CSL9C)(3) show alternate conformations and are partially preorganized for metal binding, whereas cysteines in (CSL19C)(3) are present as a single conformer. Zn(II) ions, which do not coordinate or influence Cys residues at the designed metal sites but are essential for forming X-ray quality crystals, are bound to His and Glu residues at the crystal packing interfaces of both structures. These "apo" structures are used to clarify the changes in metal site organization between metalated As(CSL9C)(3) and to speculate on the differential basis of Hg(II) binding in a versus d peptides. Thus, for the first time, one can establish general rules for heavy metal binding to Cys-rich sites in designed proteins which may provide insight for understanding how heavy metals bind to metallochaperones or metalloregulatory proteins.
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Affiliation(s)
- Saumen Chakraborty
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 (USA), Fax: (+1) 734-936-7628
| | - Debra S. Touw
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 (USA), Fax: (+1) 734-936-7628
| | - Anna F. A. Peacock
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 (USA), Fax: (+1) 734-936-7628
| | - Jeanne Stuckey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109 (USA)
| | - Vincent L. Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109 (USA), Fax: (+1) 734-936-7628
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32
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Jalilehvand F, Leung BO, Mah V. Cadmium(II) complex formation with cysteine and penicillamine. Inorg Chem 2010; 48:5758-71. [PMID: 19469490 DOI: 10.1021/ic802278r] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The complex formation between cadmium(II) and the ligands cysteine (H(2)Cys) and penicillamine (H(2)Pen = 3,3'-dimethylcysteine) in aqueous solutions, having C(Cd(II)) approximately 0.1 mol dm(-3) and C(H(2)L) = 0.2-2 mol dm(-3), was studied at pH = 7.5 and 11.0 by means of (113)Cd NMR and Cd K- and L(3)-edge X-ray absorption spectroscopy. For all cadmium(II)-cysteine molar ratios, the mean Cd-S and Cd-(N/O) bond distances were found in the ranges 2.52-2.54 and 2.27-2.35 A, respectively. The corresponding cadmium(II)-penicillamine complexes showed slightly shorter Cd-S bonds, 2.50-2.53 A, but with the Cd-(N/O) bond distances in a similar wide range, 2.28-2.33 A. For the molar ratio C(H(2)L)/C(Cd(II)) = 2, the (113)Cd chemical shifts, in the range 509-527 ppm at both pH values, indicated complexes with distorted tetrahedral CdS(2)N(N/O) coordination geometry. With a large excess of cysteine (molar ratios C(H(2)Cys)/C(Cd(II)) >or= 10), complexes with CdS(4) coordination geometry dominate, consistent with the (113)Cd NMR chemical shifts, delta approximately 680 ppm at pH 7.5 and 636-658 ppm at pH 11.0, and their mean Cd-S distances were 2.53 +/- 0.02 A. At pH 7.5, the complexes are almost exclusively sulfur-coordinated as [Cd(S-cysteinate)(4)](n-), while at higher pH, the deprotonation of the amine groups promotes chelate formation. At pH 11.0, a minor amount of the [Cd(Cys)(3)](4-) complex with CdS(3)N coordination is formed. For the corresponding penicillamine solutions with molar ratios C(H(2)Pen)/C(Cd(II)) >or= 10, the (113)Cd NMR chemical shifts, delta approximately 600 ppm at pH 7.5 and 578 ppm at pH 11.0, together with the average bond distances, Cd-S 2.53 +/- 0.02 A and Cd-(N/O) 2.30-2.33 A, indicate that [Cd(penicillaminate)(3)](n-) complexes with chelating CdS(3)(N/O) coordination dominate already at pH 7.5 and become mixed with CdS(2)N(N/O) complexes at pH 11.0. The present study reveals differences between cysteine and penicillamine as ligands to the cadmium(II) ion that can explain why cysteine-rich metallothionines are capable of capturing cadmium(II) ions, while penicillamine, clinically useful for treating the toxic effects of mercury(II) and lead(II) exposure, is not efficient against cadmium(II) poisoning.
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Affiliation(s)
- Farideh Jalilehvand
- Department of Chemistry, University of Calgary, Calgary, AB, Canada T2N 1N4.
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Mah V, Jalilehvand F. Cadmium(II) complex formation with glutathione. J Biol Inorg Chem 2009; 15:441-58. [PMID: 20035360 DOI: 10.1007/s00775-009-0616-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 12/04/2009] [Indexed: 11/24/2022]
Abstract
Complex formation between heavy metal ions and glutathione (GSH) is considered as the initial step in many detoxification processes in living organisms. In this study the structure and coordination between the cadmium(II) ion and GSH were investigated in aqueous solutions (pH 7.5 and 11.0) and in the solid state, using a combination of spectroscopic techniques. The similarity of the Cd K-edge and L(3)-edge X-ray absorption spectra of the solid compound [Cd(GS)(GSH)]ClO(4).3H(2)O, precipitating at pH 3.0, with the previously studied cysteine compound {Cd(HCys)(2).H(2)O}(2).H(3)O(+).ClO(4) (-) corresponds to Cd(S-GS)(3)O (dominating) and Cd(S-GS)(4) four-coordination within oligomeric complexes with mean bond distances of 2.51 +/- 0.02 A for Cd-S and 2.24 +/- 0.04 A for Cd-O. For cadmium(II) solutions (C (Cd(II)) approximately 0.05 M) at pH 7.5 with moderate excess of GSH (C (GSH)/C (Cd(II)) = 3.0-5.0), a mix of Cd(S-GS)(3)O (dominating) and Cd(S-GS)(4) species is consistent with the broad (113)Cd NMR resonances in the range 632-658 ppm. In alkaline solutions (pH 11.0 and C (GSH)/C (Cd(II)) = 2.0 or 3.0), two distinct peaks at 322 and 674 ppm are obtained. The first peak indicates six-coordinated mononuclear and dinuclear complexes with CdS(2)N(2)(N/O)(2) and CdSN(3)O(2) coordination in fast exchange, whereas the second corresponds to Cd(S-GS)(4) sites. At high ligand excess the tetrathiolate complex, Cd(S-GS)(4), characterized by a sharp delta((113)Cd) NMR signal at 677 ppm, predominates. The average Cd-S distance, obtained from the X-ray absorption spectra, varied within a narrow range, 2.49-2.53 A, for all solutions (pH 7.5 and 11.0) regardless of the coordination geometry.
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Affiliation(s)
- Vicky Mah
- Department of Chemistry, University of Calgary, Calgary, AB, T2N 1N4, Canada
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Jalilehvand F, Mah V, Leung BO, Mink J, Bernard GM, Hajba L. Cadmium(II) cysteine complexes in the solid state: a multispectroscopic study. Inorg Chem 2009; 48:4219-30. [PMID: 19351134 DOI: 10.1021/ic900145n] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cadmium(II) cysteinate compounds have recently been recognized to provide an environmentally friendly route for the production of CdS nanoparticles, used in semiconductors. In this article, we have studied the coordination for two cadmium(II) cysteinates, Cd(HCys)(2) x H(2)O (1) and {Cd(HCys)(2) x H(2)O}(2) x H(3)O(+)ClO(4)(-) (2), by means of vibrational (Raman and IR absorption), solid-state NMR ((113)Cd and (13)C), and Cd K- and L(3)-edge X-ray absorption spectroscopy. Indistinguishable Cd K-edge extended X-ray absorption fine structure (EXAFS) and Cd L(3)-edge X-ray absorption near edge structure (XANES) spectra were obtained for the two compounds, showing similar local structure around the cadmium(II) ions. The vibrational spectra show that the cysteine amine group is protonated (NH(3)(+)) and not involved in bonding. The (113)Cd solid-state cross-polarization magic angle spinning NMR spectra showed a broad signal in the approximately 500-700 ppm range, with the peak maximum at about 650 ppm, indicating three to four coordinated thiolate groups. Careful analyses of low-frequency Raman and far-IR spectra revealed bridging and terminal Cd-S vibrational bands. The average Cd-S distance of 2.52 +/- 0.02 A that constantly emerged from least-squares curve-fitting of the EXAFS spectra is consistent with CdS(4) and CdS(3)O coordination. Both structural models yielded reasonable values for the refined parameters, with a slightly better fit for the CdS(3)O configuration, for which the Cd-O distance of 2.27 +/- 0.04 A was obtained. The Cd L(3)-edge XANES spectra of 1 and 2 resembled that of the CdS(3)O model compound and showed that the coordination around Cd(II) ions in 1 and 2 cannot be exclusively CdS(4). The small separation of 176 cm(-1) between the infrared symmetric and antisymmetric COO(-) stretching modes indicates monodentate or strongly asymmetrical bidentate coordination of a cysteine carboxylate group in the CdS(3)O units. The combined results are consistent with a "cyclic/cage" type of structure for both the amorphous solids 1 and 2, composed of CdS(4) and CdS(3)O units with single thiolate (Cd-S-Cd) bridges, although a minor amount of cadmium(II) sites with CdS(3)O(2-3) and CdS(4)O coordination geometries cannot be ruled out.
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Affiliation(s)
- Farideh Jalilehvand
- Department of Chemistry, University of Calgary, Calgary, AB, Canada T2N 1N4.
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Peacock AFA, Iranzo O, Pecoraro VL. Harnessing natures ability to control metal ion coordination geometry using de novo designed peptides. Dalton Trans 2009:2271-80. [PMID: 19290357 DOI: 10.1039/b818306f] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Advances in protein chemistry and molecular and structural biology have empowered modern chemists to build complex biological architectures using a "first principles" approach, which is known as de novo protein design. In this Perspective we demonstrate how simple three-stranded alpha-helical constructs can be prepared by the sole consideration of the primary amino acid sequence of a peptide. With these well defined systems, we then demonstrate that metal binding cavities can be carved out of the hydrophobic cores of these aggregates in order to bind metal ions such as cadmium with well defined coordination geometries. Examples will be given of homoleptic CdS(3) complexes, CdS(3)O sites and proteins which contain equilibrium mixtures of these two species. We will provide a description of a strategy that allows us to build heterochromic peptides (small proteins that complex two metals in nearly identical environments but which result in different physical properties and allow for metal site selectivity). We conclude with a new class of designed peptides, diastereopeptides, which can exploit changes in amino acid chirality to control metal ion coordination number and lead to an alternative path towards heterochromic systems. The constructs described herein represent the initial steps of preparing protein structures that may simultaneous contain structural and catalytic metal binding centers. These studies inform the community on a developing field, which promises new opportunities for the study of bioinorganic chemistry.
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Affiliation(s)
- Anna F A Peacock
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA
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