Co(II) Coordination in Prokaryotic Zinc Finger Domains as Revealed by UV-Vis Spectroscopy

Sivo, Valeria; D’Abrosca, Gianluca; Russo, Luigi; Iacovino, Rosa; Pedone, Paolo V.; Fattorusso, Roberto; Isernia, Carla; Malgieri, Gaetano

doi:10.1155/2017/1527247

Cited by 23 publications

(35 citation statements)

References 47 publications

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“…in tetrahedral coordination. [40][41][42] The absorptionb and at 420 nm can be assigned to the d-d transitions of Cu 2 + . [39,43] The absorption band at 290 nm can be assigned to Cu 2 + .…”

Section: Resultsmentioning

confidence: 99%

“…These absorption bands can be assigned to d-d transitions of Co 2 + in at etrahedral geometry. [40][41][42] The absorption band at around4 20 nm can be assigned to either another Co-absorption band or ap ossible absorption band of Cu 2 + . [39][40][41][42][43] Again a directly proportional relationship between the absorption band intensity and the content of cobalt in the IL can be found.…”

Section: Resultsmentioning

confidence: 99%

“…Those can be assigned to assigned to d-dt ransitions of Co 2 + in at etrahedral geometry. [40][41][42] The manganese-based IL (IL13)o nly shows very weak absorption bands,F igure 6e,a t 358, 430, and 448 nm. Those can be assigned to the spin-forbidden transitions of Mn 2 + .…”

Section: Resultsmentioning

confidence: 99%

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Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

Balischewski

Behrens

Zehbe

et al. 2020

Chemistry A European J

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Thirteen N-butylpyridinium salts, including three monometallic [C 4 Py] 2 [MCl 4 ], nine bimetallic [C 4 Py] 2 [M 1Àx a M x b Cl 4 ]a nd one trimetallicc ompound [C 4 Py] 2 [M 1Ày-z a M y b M z c Cl 4 ](M = Co, Cu, Mn; x = 0.25, 0.50 or 0.75 and y = z = 0.33), were synthesized and their structure and thermala nd electrochemical properties were studied. All compoundsa re ionic liquids(ILs) with melting points between 69 and 93 8C. X-ray diffraction provest hat all ILs are isostructural. The conductivity at room temperature is be-tween1 0 À4 and1 0 À8 Scm À1 .S ome Cu-based ILs reach conductivities of 10 À2 Scm À1 ,w hichi s, however, probablyd ue to IL dec. This correlates with the opticalb andgap measurementsi ndicating the formation of large bandgap semiconductors.A te levated temperaturesa pproaching the melting points, the conductivities reach up to 1.47 10 À1 Scm À1 at 70 8C. The electrochemical stability windowso ft he ILs are between2.5 and 3.0 V.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

Balischewski

Behrens

Zehbe

et al. 2020

Chemistry A European J

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“…Zn(II)-binding sites in zinc-finger proteins, [62][63][64] whereas similar shoulders/side-peaks (although of different relative magnitudes than ours) were also seen around 575 nm and 675 nm in another zinc-finger Cys2His2 site. 65 We spectroscopically detected this second-tier Co(II)-binding site for MRP126 after >3 equivalents Co(II) were added in the presence of Ca(II) (Figure 6F). Indeed, the spectra of MRP126 with 10 equivalents Co(II) in the presence of Ca(II) appears to be a near summation of the absorption spectra of MRP126 with three equivalents Co(II) and that of the DHis3Asp variant with 10 equivalents Co(II).…”

Section: B G C H D I E Jmentioning

confidence: 97%

Avian MRP126 Restricts Microbial Growth through Ca(II)-Dependent Zn(II) Sequestration

Bozzi

Nolan

2019

Biochemistry

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The calgranulins form a class of S100 proteins in higher vertebrates that innate-immune cells release in abundance at infection sites. These proteins function by binding transition metal ions to prevent microbial pathogens from obtaining those essential nutrients. Mammals express three distinct members of this family, S100A8 (calgranulin A), S100A9 (calgranulin B, which heterooligomerizes with S100A8 to form calprotectin), and S100A12 (calgranulin C), that exhibit Ca(II)-dependent transition-metal-binding properties. Human calprotectin effectively sequesters Mn(II), Fe(II), Ni(II), and Zn(II), whereas human S100A12 selectivity sequesters Zn(II) over these other metal ions. Birds and reptiles express a single calgranulin homolog named MRP126, which we reasoned could have properties more similar to either calprotectin or S100A12. Here we present the purification and biophysical characterization of chicken MRP126 and, to the best of our knowledge, provide the first assessment of the metal-binding and antimicrobial properties of an avian MRP126. We show that MRP126 is a homodimer that selectively sequesters Zn(II) and restricts the growth of certain microbes. MRP126 binds Zn(II) at two canonical His3Asp sites. The presence of excess Ca(II) increases the affinity of the His3Asp sites from the lownanomolar to the low-picomolar range, thereby enhancing antimicrobial activity. Chicken MRP126 also binds additional Zn(II) equivalents with low-nanomolar affinity at two non-conserved dicysteine sites and with high-nanomolar affinity using a histidine-rich C-terminal tail that is a hallmark of this clade of calgranulins. Our results with chicken MRP126 suggest that Ca(II)-dependent Zn(II) sequestration was a role of the last common ancestor of calgranulin proteins, with mammalian calprotectin subsequently evolving a broader metal-binding repertoire.

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“…This transition fitted perfectly to a two-state model with a 1.010 (± 0.005) van't Hoff to calorimetric enthalpy ratio (ΔH vH ∕ΔH cal ). In order to understand the conformational determinants governing this second transition we investigated also the thermal behaviour of Ros87_C27D, a single point mutant of Ros87 in which the second coordinating cysteine is mutated in aspartate 42,43 . This mutant has been previously shown to fold around the zinc ion and to overall preserve Ros87 global fold and positions of the secondary structure elements 42 .…”

Section: Apo-ros87 and Ros87_c27d Thermal Unfoldingmentioning

confidence: 99%

The change of conditions does not affect Ros87 downhill folding mechanism

Grazioso¹,

García‐Viñuales

D’Abrosca³

et al. 2020

Sci Rep

Self Cite

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Downhill folding has been defined as a unique thermodynamic process involving a conformations ensemble that progressively loses structure with the decrease of protein stability. Downhill folders are estimated to be rather rare in nature as they miss an energetically substantial folding barrier that can protect against aggregation and proteolysis. We have previously demonstrated that the prokaryotic zinc finger protein Ros87 shows a bipartite folding/unfolding process in which a metal binding intermediate converts to the native structure through a delicate barrier-less downhill transition. Significant variation in folding scenarios can be detected within protein families with high sequence identity and very similar folds and for the same sequence by varying conditions. For this reason, we here show, by means of DSC, CD and NMR, that also in different pH and ionic strength conditions Ros87 retains its partly downhill folding scenario demonstrating that, at least in metallo-proteins, the downhill mechanism can be found under a much wider range of conditions and coupled to other different transitions. We also show that mutations of Ros87 zinc coordination sphere produces a different folding scenario demonstrating that the organization of the metal ion core is determinant in the folding process of this family of proteins.

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Co(II) Coordination in Prokaryotic Zinc Finger Domains as Revealed by UV-Vis Spectroscopy

Cited by 23 publications

References 47 publications

Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

Ionic Liquids with More than One Metal: Optical and Electrochemical Properties versus d‐Block Metal Combinations

Avian MRP126 Restricts Microbial Growth through Ca(II)-Dependent Zn(II) Sequestration

The change of conditions does not affect Ros87 downhill folding mechanism

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