Naslov
STRUCTURE PREDICTION OF PHYSIOLOGICAL BIS(AMINOACIDATO)COPPER(II) IN AQUEOUS SOLUTION: THE (L-HISTIDINATO)(L-GLUTAMINATO)COPPER(II) SYSTEM

Autori
Sabolović, Jasmina ; Ramek, Michael ; Pejić, Jelena

Kolaboracija
Projekt HrZZ IP-2004-09-3500

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Skup
12th Triennial Congress of the World Association of Theoretical and Computational Chemists

Mjesto i datum
Vancouver, Kanada, 03.07.2022. - 08.07.2022

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Bioinorgranic ; Amino acids ; Structural properties ; Conformation analysis ; Density functional calculations ; EPR g tensor and hyperfine coupling

Sažetak
Electrically neutral bis(aminoacidato)copper(II) [Cu(aa)2] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma, preferentially bound with l-histidine (His) in bis(L- histidinato)copper(II), and ternary copper(II)–l- amino acid complexes containing His. These low- molecular-weight (LMW) compounds were suggested to be part (~0.2%) of an exchangeable Cu(II) pool in human blood plasma for transport, storage, and distribution in the body [1]. Generally, LMW Cu(II) coordination compounds strongly prefer a planar configuration in solution, with Cu(II) bound with four nearby donor atoms arranged approximately in a plane around the metal ion, with the possibility of one or two more axial donor atoms at a larger distance due to the Jahn- Teller effect. When a potentially tridentate amino acid forms a chelate with Cu(II), there are many possibilities of both axial and planar bonds. Generally, the experimental studies of the physiological Cu(aa)2 complexes did not determine their exact and complete structures in solutions. This computational study resolves that missing piece of information for (l-histidinato)(l- glutaminato)copper(ll) [Cu(His)(Gln)] by exploring the structural properties and energy landscapes using the density functional theory (DFT) with the B3LYP functional. Systematic conformational analysis of Cu(His)(Gln) with various combinations of the His and Gln in-plane binding modes and apical donor atoms in implicitly modeled aqueous surroundings using a polarizable continuum model located the low-energy conformers and coordination modes. The predicted lower-energy aqueous structures were verified by the DFT calculations of the g-factor and hyperfine coupling constant (HFCC) tensor of the 63Cu (ACu) and 14N (AN) centers for a quantitative comparison to experimental electron paramagnetic resonance (EPR) data. The EPR spectrum of Cu(His)(Gln) was obtained from a frozen solution of the copper(II)/l-His/l-Gln mixture in 1:1:1 molar ratio at pH 7 frozen solutions (at 80 K) [2]. The best reproduction of the experimental EPR data was obtained for the conformers with His and Gln in- plane binding via the histaminato and glycinato mode, respectively, in a cis configuration, and with His carboxylato oxygen atom at the apical position. The aim is to gain structural properties and information on effects of intra- and intermolecular interactions on the geometry and relative stability of physiologically important Cu(aa)2 as part of their physicochemical characterization for prospective pharmacological activity and use. Acknowledgment: This work was supported by the Croatian Science Foundation under the project IP- 2014-09-3500. [1] T. Kirsipuu, A. Zadorožnaja, J. Smirnova, M. Friedemann, T. Plitz, V. Tõugu, P. Palumaa, Sci. Rep. 20 (2020) 5686. [2] P. Deschamps, N. Zerrouk, T. Martens, M.-F. Charlot, J. J. Girerd, J. C. Chaumeil, A. Tomas, J. Trace Microprobe Tech. 21 (2003) 729–741.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

Napomena
Pozvano izlaganje Jasmine Sabolović održano
04.07.2022., sekcija Invited Communications 1F

POVEZANOST RADA