1
|
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.
Collapse
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
| | | |
Collapse
|
2
|
Oranges M, Wort JL, Fukushima M, Fusco E, Ackermann K, Bode BE. Pulse Dipolar Electron Paramagnetic Resonance Spectroscopy Reveals Buffer-Modulated Cooperativity of Metal-Templated Protein Dimerization. J Phys Chem Lett 2022; 13:7847-7852. [PMID: 35976741 PMCID: PMC9421889 DOI: 10.1021/acs.jpclett.2c01719] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 08/10/2022] [Indexed: 05/26/2023]
Abstract
Self-assembly of protein monomers directed by metal ion coordination constitutes a promising strategy for designing supramolecular architectures complicated by the noncovalent interaction between monomers. Herein, two pulse dipolar electron paramagnetic resonance spectroscopy (PDS) techniques, pulse electron-electron double resonance and relaxation-induced dipolar modulation enhancement, were simultaneously employed to study the CuII-templated dimerization behavior of a model protein (Streptococcus sp. group G, protein G B1 domain) in both phosphate and Tris-HCl buffers. A cooperative binding model could simultaneously fit all data and demonstrate that the cooperativity of protein dimerization across α-helical double-histidine motifs in the presence of CuII is strongly modulated by the buffer, representing a platform for highly tunable buffer-switchable templated dimerization. Hence, PDS enriches the family of techniques for monitoring binding processes, supporting the development of novel strategies for bioengineering structures and stable architectures assembled by an initial metal-templated dimerization.
Collapse
|
3
|
Abstract
Zn2+ ions are essential in many physiological processes, including enzyme catalysis, protein structural stabilization, and the regulation of many proteins. The affinities of proteins for Zn2+ ions span several orders of magnitude, with catalytic Zn2+ ions generally held more tightly than structural or regulatory ones. Metal carrier proteins, most of which are not specific for Zn2+, bind these ions with a broad range of affinities that overlap those of catalytic, structural, and regulatory Zn2+ ions and are thought to be responsible for distributing the metal through most cells, tissues, and fluid compartments. While little is known about how many proteins obtain or release these ions, there is now considerable experimental evidence suggesting that metal carrier proteins may be responsible for transferring metals to and from some Zn2+-dependent proteins, thus serving as a major regulatory factor for them. In this review, the biological roles of Zn2+ and structures of Zn2+ binding sites are examined, and experimental evidence demonstrating the direct participation of metal carrier proteins in enzyme regulation is discussed. Mechanisms of metal ion transfer are also offered, and the potential physiological significance of this phenomenon is explored.
Collapse
|
4
|
Edmonds KA, Jordan MR, Giedroc DP. COG0523 proteins: a functionally diverse family of transition metal-regulated G3E P-loop GTP hydrolases from bacteria to man. Metallomics 2021; 13:6327566. [PMID: 34302342 PMCID: PMC8360895 DOI: 10.1093/mtomcs/mfab046] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/15/2021] [Indexed: 01/13/2023]
Abstract
Transition metal homeostasis ensures that cells and organisms obtain sufficient metal to meet cellular demand while dispensing with any excess so as to avoid toxicity. In bacteria, zinc restriction induces the expression of one or more Zur (zinc-uptake repressor)-regulated Cluster of Orthologous Groups (COG) COG0523 proteins. COG0523 proteins encompass a poorly understood sub-family of G3E P-loop small GTPases, others of which are known to function as metallochaperones in the maturation of cobalamin (CoII) and NiII cofactor-containing metalloenzymes. Here, we use genomic enzymology tools to functionally analyse over 80 000 sequences that are evolutionarily related to Acinetobacter baumannii ZigA (Zur-inducible GTPase), a COG0523 protein and candidate zinc metallochaperone. These sequences segregate into distinct sequence similarity network (SSN) clusters, exemplified by the ZnII-Zur-regulated and FeIII-nitrile hydratase activator CxCC (C, Cys; X, any amino acid)-containing COG0523 proteins (SSN cluster 1), NiII-UreG (clusters 2, 8), CoII-CobW (cluster 4), and NiII-HypB (cluster 5). A total of five large clusters that comprise ≈ 25% of all sequences, including cluster 3 which harbors the only structurally characterized COG0523 protein, Escherichia coli YjiA, and many uncharacterized eukaryotic COG0523 proteins. We also establish that mycobacterial-specific protein Y (Mpy) recruitment factor (Mrf), which promotes ribosome hibernation in actinomycetes under conditions of ZnII starvation, segregates into a fifth SSN cluster (cluster 17). Mrf is a COG0523 paralog that lacks all GTP-binding determinants as well as the ZnII-coordinating Cys found in CxCC-containing COG0523 proteins. On the basis of this analysis, we discuss new perspectives on the COG0523 proteins as cellular reporters of widespread nutrient stress induced by ZnII limitation.
Collapse
Affiliation(s)
- Katherine A Edmonds
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA
| | - Matthew R Jordan
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - David P Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102, USA.,Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| |
Collapse
|
5
|
King M, Kubo A, Kafer L, Braga R, McLeod D, Khanam S, Conway T, Patrauchan MA. Calcium-Regulated Protein CarP Responds to Multiple Host Signals and Mediates Regulation of Pseudomonas aeruginosa Virulence by Calcium. Appl Environ Microbiol 2021; 87:e00061-21. [PMID: 33674436 PMCID: PMC8117776 DOI: 10.1128/aem.00061-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/27/2021] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen causing life-threatening infections. Previously, we showed that elevated calcium (Ca2+) levels increase the production of virulence factors in P. aeruginosa In an effort to characterize the Ca2+ regulatory network, we identified a Ca2+-regulated β-propeller protein, CarP, and showed that expression of the encoding gene is controlled by the Ca2+-regulated two-component system CarSR. Here, by using a Galleria melonella model, we showed that CarP plays a role in regulating P. aeruginosa virulence. By using transcriptome sequencing (RNA-Seq), reverse transcription (RT)-PCR, quantitative RT-PCR (RT-qPCR), and promoter fusions, we determined that carP is transcribed into at least two transcripts and regulated by several bacterial and host factors. The transcription of carP is elevated in response to Ca2+ in P. aeruginosa cystic fibrosis isolates and PAO1 laboratory strain. Elevated Fe2+ also induces carP The simultaneous addition of Ca2+ and Fe2+ increased the carP promoter activity synergistically, which requires the presence of CarR. In silico analysis of the intergenic sequence upstream of carP predicted recognition sites of RhlR/LasR, OxyR, and LexA, suggesting regulation by quorum sensing (QS) and oxidative stress. In agreement, the carP promoter was activated in response to stationary-phase PAO1 supernatant and required the presence of elevated Ca2+ and CarR but remained silent in the triple mutant lacking rhlI, lasI, and pqsA synthases. We also showed that carP transcription is regulated by oxidative stress and that CarP contributes to P. aeruginosa Ca2+-dependent H2O2 tolerance. The multifactorial regulation of carP suggests that CarP plays an important role in P. aeruginosa adaptations to host environments.IMPORTANCEP. aeruginosa is a human pathogen causing life-threatening infections. It is particularly notorious for its ability to adapt to diverse environments within the host. Understanding the signals and the signaling pathways enabling P. aeruginosa adaptation is imperative for developing effective therapies to treat infections caused by this organism. One host signal of particular importance is calcium. Previously, we identified a component of the P. aeruginosa calcium-signaling network, CarP, whose expression is induced by elevated levels of calcium. Here, we show that carP plays an important role in P. aeruginosa virulence and is upregulated in P. aeruginosa strains isolated from sputa of patients with cystic fibrosis. We also identified several bacterial and host factors that regulate the transcription of carP Such multifactorial regulation highlights the interconnectedness between regulatory circuits and, together with the pleotropic effect of CarP on virulence, suggests the importance of this protein in P. aeruginosa adaptations to the host.
Collapse
Affiliation(s)
- Michelle King
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Aya Kubo
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Leah Kafer
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Reygan Braga
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Daniel McLeod
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Sharmily Khanam
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Tyrrell Conway
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Marianna A Patrauchan
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| |
Collapse
|
6
|
Meni A, Yukl ET. Structural Features Mediating Zinc Binding and Transfer in the AztABCD Zinc Transporter System. Biomolecules 2020; 10:biom10081156. [PMID: 32781785 PMCID: PMC7463823 DOI: 10.3390/biom10081156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/27/2022] Open
Abstract
Many bacteria require ATP binding cassette (ABC) transporters for the import of the essential metal zinc from limited environments. These systems rely on a periplasmic or cell-surface solute binding protein (SBP) to bind zinc with high affinity and specificity. AztABCD is one such zinc transport system recently identified in a large group of diverse bacterial species. In addition to a classical SBP (AztC), the operon also includes a periplasmic metallochaperone (AztD) shown to transfer zinc directly to AztC. Crystal structures of both proteins from Paracoccus denitrificans have been solved and suggest several structural features on each that may be important for zinc binding and transfer. Here we determine zinc binding affinity, dissociation kinetics, and transfer kinetics for several deletion mutants as well as a crystal structure for one of them. The results indicate specific roles for loop structures on AztC and an N-terminal motif on AztD in zinc binding and transfer. These data are consistent with a structural transfer model proposed previously and provide further mechanistic insight into the processes of zinc binding and transfer.
Collapse
|