Superconducting high-resolution X-ray detectors for metalloprotein L-edge spectroscopy

Friedrich, S.; Hiller, L. J.; Frank, Matthias; Grand, Johan; Mears, C. A.; Nideröst, B.; Labov, S. E.; Barfknecht, A.T.; LeGros, Mark; Cramer, Stephen P.

doi:10.1016/s0368-2048(98)00410-1

Cited by 11 publications

(7 citation statements)

References 18 publications

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“…For biological samples or dilute NiBr 2 matrix samples, XAS were measured by partial X-ray fluorescence yield (PFY) 12, 31 using a 30-element germanium (Ge) array detector with 180 eV energy resolution, or a 9- or 36-element superconducting tunnel junction (STJ) detector with 15 eV energy resolution. 39,40 For measuring < 0.1% Ni Ct -CODH, the use of an STJ detector was necessary to extract the weak Ni signal from the high spectral background. During these measurements, one region was defined around Ni L, Cu L or Ce M partial fluorescence signal (PF), which is proportional to the metal absorbance and incident X-ray beam intensity, while the second region was set at around the oxygen (O) K fluorescence signal used as a measure of I 0 .…”

Section: Methodsmentioning

confidence: 99%

L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes

Wang

Friedrich

et al. 2018

Phys. Chem. Chem. Phys.

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According to L-edge sum rules, the number of 3d vacancies at a transition metal site is directly proportional to the integrated intensity of the L-edge X-ray absorption spectrum (XAS) for the corresponding metal complex. In this study, the numbers of 3d holes are characterized quantitatively or semi-quantitatively for a series of manganese (Mn) and nickel (Ni) complexes, including the electron configurations 3d→ 3d. In addition, extremely dilute (<0.1% wt/wt) Ni enzymes were examined by two different approaches: (1) by using a high resolution superconducting tunnel junction X-ray detector to obtain XAS spectra with a very high signal-to-noise ratio, especially in the non-variant edge jump region; and (2) by adding an inert tracer to the sample that provides a prominent spectral feature to replace the weak edge jump for intensity normalization. In this publication, we present for the first time: (1) L-edge sum rule analysis for a series of Mn and Ni complexes that include electron configurations from an open shell 3d to a closed shell 3d; (2) a systematic analysis on the uncertainties, especially on that from the edge jump, which was missing in all previous reports; (3) a clearly-resolved edge jump between pre-L and post-L regions from an extremely dilute sample; (4) an evaluation of an alternative normalization standard for L-edge sum rule analysis. XAS from two copper (Cu) proteins measured using a conventional semiconductor X-ray detector are also repeated as bridges between Ni complexes and dilute Ni enzymes. The differences between measuring 1% Cu enzymes and measuring <0.1% Ni enzymes are compared and discussed. This study extends L-edge sum rule analysis to virtually any 3d metal complex and any dilute biological samples that contain 3d metals.

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Section: Methodsmentioning

confidence: 99%

L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes

Wang

Friedrich

et al. 2018

Phys. Chem. Chem. Phys.

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“…Therefore, collecting partial fluorescence yield (PFY)-detected XAS instead of TFY by energy-discriminating other fluorescence signals is mandatory. So far, and to the best of our knowledge, the only approach for separating the Mn L- and the O K-fluorescence for PFY XAS was done with a superconducting solid state detector with 20 eV resolution 36 (see Supporting Information Figure S1). This detector, however, is not suitable for our aims to measure XAS at an XFEL, because it operates in single-photon counting mode with low repetition rates.…”

mentioning

confidence: 99%

L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser

Mitzner

Rehanek

Kern

et al. 2013

J. Phys. Chem. Lett.

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L-edge spectroscopy of 3d transition metals provides important electronic structure information and has been used in many fields. However, the use of this method for studying dilute aqueous systems, such as metalloenzymes, has not been prevalent because of severe radiation damage and the lack of suitable detection systems. Here we present spectra from a dilute Mn aqueous solution using a high-transmission zone-plate spectrometer at the Linac Coherent Light Source (LCLS). The spectrometer has been optimized for discriminating the Mn L-edge signal from the overwhelming O K-edge background that arises from water and protein itself, and the ultrashort LCLS X-ray pulses can outrun X-ray induced damage. We show that the deviations of the partial-fluorescence yield-detected spectra from the true absorption can be well modeled using the state-dependence of the fluorescence yield, and discuss implications for the application of our concept to biological samples.

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“…We have developed superconducting Nb-Al-AlOx-Al-Nb EUV and X-ray detectors for high-resolution spectroscopy in astrophysics, material science and biophysics [8], [9]. They consist of a 265 nm bottom Nb film and a 50 nm bottom Al trap, which is oxidized to form a thin AlOx tunneling barrier, a top 50 nm Al trap and a 165 nm Nb absorber film.…”

Section: A Experimental Setupmentioning

confidence: 99%

Line-splitting in high-resolution superconducting tunnel junction EUV detectors

Friedrich

Hiller

Cunningham

et al. 2001

IEEE Trans. Appl. Supercond.

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Superconducting high-resolution X-ray detectors for metalloprotein L-edge spectroscopy

Cited by 11 publications

References 18 publications

L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes

L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes

L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser

Line-splitting in high-resolution superconducting tunnel junction EUV detectors

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Superconducting high-resolution X-ray detectors for metalloprotein L-edge spectroscopy

Cited by 11 publications

References 18 publications

L-edge sum rule analysis on 3d transition metal sites: from d10to d0and towards application to extremely dilute metallo-enzymes

L-edge sum rule analysis on 3d transition metal sites: from d10to d0and towards application to extremely dilute metallo-enzymes

L-Edge X-ray Absorption Spectroscopy of Dilute Systems Relevant to Metalloproteins Using an X-ray Free-Electron Laser

Line-splitting in high-resolution superconducting tunnel junction EUV detectors

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Product

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L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes

L-edge sum rule analysis on 3d transition metal sites: from d¹⁰to d⁰and towards application to extremely dilute metallo-enzymes