TY - JOUR

T1 - XANES measurements for studies of adsorbed protein layers at liquid interfaces

AU - Konovalov, Oleg V.

AU - Novikova, Natalia N.

AU - Kovalchuk, Mikhail V.

AU - Yalovega, Galina E.

AU - Topunov, Alexey F.

AU - Kosmachevskaya, Olga V.

AU - Yurieva, Eleonora A.

AU - Rogachev, Alexander V.

AU - Trigub, Alexander L.

AU - Kremennaya, Maria A.

AU - Borshchevskiy, Valentin I.

AU - Vakhrameev, Daniil D.

AU - Yakunin, Sergey N.

N1 - Publisher Copyright: © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2020/10/2

Y1 - 2020/10/2

N2 - 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.

AB - 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.

KW - Langmuir trough

KW - Metalloproteins

KW - Protein layers at liquid interface

KW - XANES

KW - Zinc binding sites

UR - http://www.scopus.com/inward/record.url?scp=85093848748&partnerID=8YFLogxK

U2 - 10.3390/ma13204635

DO - 10.3390/ma13204635

M3 - Article

AN - SCOPUS:85093848748

VL - 13

SP - 1

EP - 12

JO - Materials

JF - Materials

SN - 1996-1944

IS - 20

M1 - 4635

ER -