Rotational correlation times of proteins determined by 111mCd PAC spectroscopy

Fromsejer, Rasmus; Hemmingsen, Lars

doi:10.1007/s10751-019-1626-3

Cited by 2 publications

(3 citation statements)

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“…The rotational correlation time of the protein, see Table , is the same in both experiments. The theoretical value for the global rotational correlation time is 1 μs −1 , using the Stokes–Einstein approximation for the rotational diffusion, a molecular weight of the protein dimer of 30 500 Da, and a radius of hydration of 3 Å. This is slightly smaller than the experimental value of 6(4) μs −1 , implying that there may be a component of local dynamics contributing to the observed rotational diffusion, in agreement with the disordered metal ion binding loop observed by X‐ray diffraction .…”

Section: Resultsmentioning

confidence: 99%

“…TheC -terminal CCHH motif could provide the additional cysteines, in analogyt ow hat has been proposed for Hg II bound to CueR. [34] It is noteworthy that the 111 Ag and 111m Cd PACe xperiments at 1 8Cg ive very differentN QIs, demonstrating that the structure occupied by Cd II at 1 8Cd erived from the 111 Ag spectrumi satransient species.T he rotational correlation time of the protein, see Ta ble1,i st he same in both experiments.T he theoretical value fort he global rotational correlation time is 1 ms À1 ,u sing the Stokes-Einstein approximation for the rotational diffusion, [31] am olecular weight of the protein dimer of 30 500 Da, and ar adius of hydration of 3 .T his is slightly smaller than the experimental value of 6(4) ms À1 ,i mplying that there may be ac omponent of local dynamics contributing to the observed rotational diffusion, in agreement with the disordered metal ion binding loop observed by X-ray diffraction. [5] Thus dynamics affects the metal ion binding loop at the level of thermal energy.…”

Section: Resultsmentioning

confidence: 99%

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Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Balogh

Gyurcsik

Jensen

et al. 2020

Chemistry A European J

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Selectivity for monovalent metal ions is an important facet of the function of the metalloregulatory protein CueR. 111Ag perturbed angular correlation of γ‐rays (PAC) spectroscopy probes the metal site structure and the relaxation accompanying the instantaneous change from AgI to CdII upon 111Ag radioactive decay. That is, a change from AgI, which activates transcription, to CdII, which does not. In the frozen state (−196 °C) two nuclear quadrupole interactions (NQIs) are observed; one (NQI1) agrees well with two coordinating thiolates and an additional longer contact to the S77 backbone carbonyl, and the other (NQI2) reflects that CdII has attracted additional ligand(s). At 1 °C only NQI2 is observed, demonstrating that relaxation to this structure occurs within ≈10 ns of the decay of 111Ag. Thus, transformation from AgI to CdII rapidly disrupts the functional linear bis(thiolato)AgI metal site structure. This inherent metal site flexibility may be central to CueR function, leading to remodelling into a non‐functional structure upon binding of non‐cognate metal ions. In a broader perspective, 111Ag PAC spectroscopy may be applied to probe the flexibility of protein metal sites.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Balogh

Gyurcsik

Jensen

et al. 2020

Chemistry A European J

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“…Several past PAC studies have reported the effect of dynamics on the spectroscopic signal. [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] However, the molecular motion comprises both global rotational diffusion and local intramolecular dynamics, and thus, in most cases, the effective, combined dynamics of the molecule were observed.…”

Section: Introductionmentioning

confidence: 99%

Molecular Rotational Correlation Times and Nanoviscosity Determined by ^111mCd Perturbed Angular Correlation (PAC) of γ‐rays Spectroscopy

Fromsejer

Jensen

Zacate

et al. 2022

Chemistry A European J

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The nanoviscosity experienced by molecules in solution may be determined through measurement of the molecular rotational correlation time, τc, for example, by fluorescence and NMR spectroscopy. With this work, we apply PAC spectroscopy to determine the rate of rotational diffusion, λ=1/τc, of a de novo designed protein, TRIL12AL16C, in solutions with viscosities, ξ, from 1.7 to 88 mPa⋅s. TRIL12AL16C was selected as molecular probe because it exhibits minimal effects due to intramolecular dynamics and static line broadening, allowing for exclusive elucidation of molecular rotational diffusion. Diffusion rates determined by PAC data agree well with literature data from fluorescence and NMR spectroscopy, and scales linearly with 1/ξ in agreement with the Stokes–Einstein–Debye model. PAC experiments require only trace amounts (∼1011) of probe nuclei and can be conducted over a broad range of sample temperatures and pressures. Moreover, most materials are relatively transparent to γ‐rays. Thus, PAC spectroscopy could find applications under circumstances where conventional techniques cannot be applied, spanning from the physics of liquids to in‐vivo biochemistry.

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Rotational correlation times of proteins determined by 111mCd PAC spectroscopy

Cited by 2 publications

References 32 publications

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Molecular Rotational Correlation Times and Nanoviscosity Determined by ^111mCd Perturbed Angular Correlation (PAC) of γ‐rays Spectroscopy

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Rotational correlation times of proteins determined by 111mCd PAC spectroscopy

Cited by 2 publications

References 32 publications

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from AgI to CdII

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from AgI to CdII

Molecular Rotational Correlation Times and Nanoviscosity Determined by 111mCd Perturbed Angular Correlation (PAC) of γ‐rays Spectroscopy

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Product

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Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Flexibility of the CueR Metal Site Probed by Instantaneous Change of Element and Oxidation State from Ag^I to Cd^II

Molecular Rotational Correlation Times and Nanoviscosity Determined by ^111mCd Perturbed Angular Correlation (PAC) of γ‐rays Spectroscopy