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Hecel A, Garstka K, Kozłowski H, Rowińska-Żyrek M. -HH and -HAAAH motifs act as fishing nets for biologically relevant metal ions in metallopeptides. J Inorg Biochem 2024; 252:112456. [PMID: 38154408 DOI: 10.1016/j.jinorgbio.2023.112456] [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: 10/26/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 12/30/2023]
Abstract
Histidine are one of the most common residues involved in transition metal ion binding in the active sites of metalloenzymes. In order to mimic enzymatic metal binding sites, it is crucial to understand the basic coordination modes of histidine residues, distributed at different positions in the peptide sequence. We show that: (i) the separation of two histidines has a large effect on complex stability - a sequence with adjusting histidine residues forms more stable complexes with Zn(II) than the one in which the residues are separated, while the contrary is observed for Cu(II) complexes, in which amide nitrogens participate in metal binding. No pronounced effect is observed for Ni(II) complexes, where the amides participate in binding at higher pH; (ii) non-coordinating amino acid residues (basic, acidic and aromatic ones) have a significant impact on complex stability; charged and aromatic residues may enhance Zn(II) binding, while the contrary is observed for the amide-binding Cu(II); (iii) cysteine containing sequences are much more effective Zn(II) and Ni(II) binding motifs at pH above 8, while histidine containing ligands are more suitable for effective Zn(II) and Ni(II) binding at lower pH.
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Affiliation(s)
- Aleksandra Hecel
- Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland.
| | - Kinga Garstka
- Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland
| | - Henryk Kozłowski
- Faculty of Chemistry, University of Wrocław, 50-383 Wrocław, Poland; Faculty of Health Sciences, University of Opole, 68 Katowicka St., 45-060 Opole, Poland
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Garstka K, Bellotti D, Wątły J, Kozłowski H, Remelli M, Rowińska-Żyrek M. Metal coordination to solute binding proteins - exciting chemistry with potential biological meaning. Dalton Trans 2023; 52:16140-16150. [PMID: 37814857 DOI: 10.1039/d3dt02417b] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Zn(II) is essential for bacterial survival and virulence. In host cells, its abundance is extremely limited, thus, bacteria have evolved transport mechanisms that enable them to take up this essential metal nutrient. Paracoccus denitrificans encodes two solute binding proteins (SBPs) - ZnuA and AztC, which are responsible for zinc acquisition from the host cells. We focus on understanding the interactions of Zn(II) and Ni(II) (zinc's potential competitor, which is a biologically relevant metal ion essential for various bacterial enzymes) with the extracellular ZnuA and AztC's loops from P. denitrificans that are expected to be possible Zn(II) binding sites. In the case of Zn(II) complexes with ZnuA outercellular loop regions, the numerous histidines act as anchoring donors, forming complexes with up to four coordinated His residues, while in the AztC region, three imidazole nitrogens and one water molecule are involved in Zn(II) binding. In Zn(II) complexes with ZnuA His-rich loop regions, so-called polymorphic binding sites are observed. The large number of available imidazoles and carboxylic side chains also strongly affects the structure of Ni(II) complexes; the more histidines in the studied peptide, the higher the affinity to bind Ni(II) and the higher the pH value at which amide nitrogens start to participate in Ni(II) binding. Additionally, for Ni(II)-ZnuA complexes, a more rare octahedral geometry is observed and such complexes are more stable than the corresponding Zn(II) ones, in contrast to what was observed in the AztC region, suggesting that the numerous histidyl and glutamic acid side chains are more tempting for Ni(II) than for Zn(II).The general strong affinity of Zn(II)-zincophore complexes is also discussed.
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Affiliation(s)
- Kinga Garstka
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Denise Bellotti
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17, 44121 Ferrara, Italy
| | - Joanna Wątły
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
| | - Henryk Kozłowski
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
- Institute of Health Sciences, University of Opole, Katowicka 68 St, 45-060 Opole, Poland
| | - Maurizio Remelli
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17, 44121 Ferrara, Italy
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Bellotti D, Leveraro S, Remelli M. Metal-protein solution interactions investigated using model systems: Thermodynamic and spectroscopic methods. Methods Enzymol 2023; 687:279-341. [PMID: 37666636 DOI: 10.1016/bs.mie.2023.05.004] [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] [Indexed: 09/06/2023]
Abstract
The first-row D-block metal ions are essential for the physiology of living organisms, functioning as cofactors in metalloproteins or structural components for enzymes: almost half of all proteins require metals to perform the biological function. Understanding metal-protein interactions is crucial to unravel the mysteries behind molecular biology, understanding the effects of metal imbalance and toxicity or the diseases due to disorders in metal homeostasis. Metal-protein interactions are dynamic: they are noncovalent and affected by the environment to which the system is exposed. To reach a complete comprehension of the system, different conditions must be considered for the experimental investigation, in order to get information on the species distribution, the ligand coordination modes, complex stoichiometry and geometry. Thinking about the whole environment where a protein acts, investigations are often challenging, and simplifications are required to study in detail the mechanisms of metal interaction. This chapter is intended to help researchers addressing the problem of the complexity of metal-protein interactions, with particular emphasis on the use of peptides as model systems for the metal coordination site. The thermodynamic and spectroscopic methods most widely employed to investigate the interaction between metal ions and peptides in solution are here covered. These include solid-phase peptide synthesis, potentiometric titrations, calorimetry, electrospray ionization mass spectrometry, UV-Vis spectrophotometry, circular dichroism (CD), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). Additional experimental methods, which can be employed to study metal complexes with peptides, are also briefly mentioned. A case-study is finally reported providing a practical example of the investigation of metal-protein interaction by means of thermodynamic and spectroscopic methods applied to peptide model systems.
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Affiliation(s)
- Denise Bellotti
- University of Ferrara, Department of Chemical, Pharmaceutical and Agricultural Sciences, via L. Borsari, Ferrara, Italy; Faculty of Chemistry, University of Wrocław, F. Joliot-Curie, Wrocław, Poland
| | - Silvia Leveraro
- University of Ferrara, Department of Chemical, Pharmaceutical and Agricultural Sciences, via L. Borsari, Ferrara, Italy
| | - Maurizio Remelli
- University of Ferrara, Department of Chemical, Pharmaceutical and Agricultural Sciences, via L. Borsari, Ferrara, Italy.
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Structural and biochemical characterization of Acinetobacter baumannii ZnuA. J Inorg Biochem 2022; 231:111787. [DOI: 10.1016/j.jinorgbio.2022.111787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/27/2022] [Accepted: 03/06/2022] [Indexed: 11/19/2022]
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Radka CD, Aller SG. Site 2 of the Yersinia pestis substrate-binding protein YfeA is a dynamic surface metal-binding site. Acta Crystallogr F Struct Biol Commun 2021; 77:286-293. [PMID: 34473105 PMCID: PMC8411934 DOI: 10.1107/s2053230x21008086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 08/05/2021] [Indexed: 11/10/2022] Open
Abstract
The substrate-binding protein YfeA (also known as YPO2439 or y1897) is a polyspecific metal-binding protein that is crucial for nutrient acquisition and virulence in Yersinia pestis, the causative microbe of plague. YfeA folds into a monomeric c-clamp like other substrate-binding proteins and has two metal-binding sites (sites 1 and 2). Site 2 is a bidentate surface site capable of binding Zn and Mn atoms and is a unique feature of YfeA. Occasionally, the site 2 residues of two YfeA molecules will cooperate with the histidine tag of a third YfeA molecule in coordinating the same metal and lead to metal-dependent crystallographic packing. Here, three crystal structures of YfeA are presented at 1.85, 2.05 and 2.25 Å resolution. A comparison of the structures reveals that the metal can be displaced at five different locations ranging from ∼4 to ∼16 Å away from the canonical site 2. These observations reveal different configurations of site 2 that enable cooperative metal binding and demonstrate how site 2 is dynamic and freely available for inter-protein metal coordination.
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Affiliation(s)
- Christopher D. Radka
- Department of Infectious Diseases, St Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Stephen G. Aller
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Pandeya A, Ojo I, Alegun O, Wei Y. Periplasmic Targets for the Development of Effective Antimicrobials against Gram-Negative Bacteria. ACS Infect Dis 2020; 6:2337-2354. [PMID: 32786281 PMCID: PMC8187054 DOI: 10.1021/acsinfecdis.0c00384] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Antibiotic resistance has emerged as a serious threat to global public health in recent years. Lack of novel antimicrobials, especially new classes of compounds, further aggravates the situation. For Gram-negative bacteria, their double layered cell envelope and an array of efflux pumps act as formidable barriers for antimicrobials to penetrate. While cytoplasmic targets are hard to reach, proteins in the periplasm are clearly more accessible, as the drug only needs to breach the outer membrane. In this review, we summarized recent efforts on the validation and testing of periplasmic proteins as potential antimicrobial targets and the development of related inhibitors that either inhibit the growth of a bacterial pathogen or reduce its virulence during interaction with host cells. We conclude that the periplasm contains a promising pool of novel antimicrobial targets that should be scrutinized more closely for the development of effective treatment against multidrug-resistant Gram-negative bacteria.
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Affiliation(s)
- Ankit Pandeya
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Isoiza Ojo
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Olaniyi Alegun
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Yinan Wei
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, United States
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Bellotti D, Rowińska-Żyrek M, Remelli M. Novel insights into the metal binding ability of ZinT periplasmic protein from Escherichia coli and Salmonella enterica. Dalton Trans 2020; 49:9393-9403. [PMID: 32588863 DOI: 10.1039/d0dt01626h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The ZinT mediated Zn(ii) uptake is one of the major differences in the metabolism of human and bacterial cells that can be challenged when looking for possible highly selective metal-based therapeutics. ZinT is a 216-amino acid periplasmic protein expressed by Gram-negative bacteria, which shuttles Zn(ii) ions to the ZnuABC transporter under zinc-limiting conditions. The suggested metal-binding sites of ZinT correspond to a domain containing three highly conserved histidine residues (His 167, 176 and 178) and to the N-terminal histidine-rich loop HGHHXH (residues 24-29). The coordination chemistry of the ZinT complexes with Zn(ii) and Cu(ii) has been investigated. The present work is focused on the protected peptides Ac-24HGHHSH29-NH2 and Ac-166DHIIAPRKSSHFH178-NH2 as models for the putative metal binding sites of ZinT from Escherichia coli (EcZinT), and Ac-24HGHHAH29-NH2 and Ac-166DHIIAPRKSAHFH178-NH2 from the ZinT protein expressed by Salmonella enterica sv. Typhimurium (SeZinT). The investigated peptides are able to form stable mono-nuclear complexes where the histidine residues represent the principal metal anchoring sites. The ZnuA (a periplasmic component of the ZnuABC transporter) metal binding site exhibits higher affinity for Zn(ii) than ZinT, suggesting that the interaction of the two proteins through the formation of a binary complex may involve the metal transfer from ZinT to ZnuA. In contrast, this would not occur in Cu(ii), since the ZinT complexes are more stable. Furthermore, at acidic pH, where the antimicrobial peptide calcitermin is biologically active, it also binds the metal ions with higher affinity than ZinT, representing a possible efficient competitor and antagonist of ZinT in the host human organism.
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Affiliation(s)
- Denise Bellotti
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Luigi Borsari 46, 44121 Ferrara, Italy.
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