XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces

Materials

OlgaV. Kosmachevskaya¹  AlexeyF. Topunov¹  OlegV. Konovalov²  MariaA. Kremennaya³  GalinaE. Yalovega³  DaniilD. Vakhrameev⁴  ValentinI. Borshchevskiy⁴  AlexanderV. Rogachev⁵  AlexanderL. Trigub⁵  NataliaN. Novikova⁵  MikhailV. Kovalchuk⁵  SergeyN. Yakunin⁵  EleonoraA. Yurieva⁶ 

[1] Bach Institute of Biochemistry, Federal Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia;European Synchrotron Radiation Facility, 38043 Grenoble, France;Faculty of Physics, Southern Federal University, 344006 Rostov-on-Don, Russia;Moscow Institute of Physics and Technology, Dolgoprudny, 141701 Moscow Region, Russia;National Research Center “Kurchatov Institute”, 123182 Moscow, Russia;Veltischev Research and Clinical Institute for Paediatrics, Pirogov Russian National Research Medical University, 117997 Moscow, Russia;

关键词: metalloproteins;    XANES;    zinc binding sites;    protein layers at liquid interface;    Langmuir trough;   

DOI  :  10.3390/ma13204635

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown