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XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces.

ABSTRACT: X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation condition of measurements (short exposition time) and with high X-ray radiation load. XANES fingerprint analysis was applied to obtain information on ligand environments around zinc ions. Two types of zinc coordination geometry were identified depending on X-ray radiation load. We found that, under mild conditions, local zinc environment in our parkin preparations was very similar to that identified in hemoglobin, treated with a solution of ZnCl2 salt. Under high X-ray radiation load, considerable changes in the zinc site structure were observed; local zinc environment appeared to be almost identical to that defined in Zn-containing enzyme alkaline phosphatase. The formation of a similar metal site in unrelated protein molecules, observed in our experiments, highlights the significance of metal binding templates as essential structural modules in protein macromolecules.

SUBMITTER: Konovalov OV

PROVIDER: S-EPMC7603035 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces.

Konovalov Oleg V OV Novikova Natalia N NN Kovalchuk Mikhail V MV Yalovega Galina E GE Topunov Alexey F AF Kosmachevskaya Olga V OV Yurieva Eleonora A EA Rogachev Alexander V AV Trigub Alexander L AL Kremennaya Maria A MA Borshchevskiy Valentin I VI Vakhrameev Daniil D DD Yakunin Sergey N SN

Materials (Basel, Switzerland) 20201017 20

X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation ...[more]

PMID: 33080816

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XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces.

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XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces.

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