TY  - CONF
AU  - Dimitrijević, Milena
AU  - Bogdanović Pristov, Jelena
AU  - Žižić, Milan
AU  - Stanković, Dalibor
AU  - Bajuk-Bogdanović, Danica
AU  - Stanić, Marina
AU  - Hagen, Wilfred
AU  - Piccioli, Mario
AU  - Spasojević, Ivan
PY  - 2019
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/3187
AB  - The structure of biliverdin (BV) and its complexion capacity with Cu2+ in dependence of
solvent choice has been examined. We first examined coordinate/redox interactions of BV
with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman
spectroscopy, 1HNMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable
coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more
planar and energetically stable in the complex. The complex showed strong paramagnetic
effects that were attributed to an unpaired delocalized e−. The delocalized electron may come
from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+
or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of
both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing
agents. The biological effects of the stable BV metallocomplex containing a delocalized
unpaired electron should be further examined, and may provide an answer to the longstanding
question of high energy investment in the catabolism of BV, which represents a
relatively harmless molecule per se. The complex possibility was quite different after
changing the solvent. BV structure in DMSO was analyzed by using NMR techniques and
unrestricted density function theory simulations to explain the incapacity of BV to build
coordination complex(es) with Cu2+ in dimethyl sulfoxide, which was confirmed by UV-Vis,
EPR and NMR spectroscopy. NMR showed that N atoms of BV are protonated in all four
pyrrole rings. The structure is stabilized by two hydrogen bonds between NH moieties and
carbonyl oxygens from opposite terminal pyrrole rings, and by the bending of propionyl chain
with carboxyl group out of the plain toward central position of BV. The simulations of
deprotonated BV, which builds copper complexes in water and chloroform as described
previously, showed a different conformation and organization of hydrogen bonds. Taking into
account that deprotonation represents a critical step in coordinate bonds formation, the
protonation of an additional N atom may represent a key difference between the interactions
of BV with copper in different solvents.
PB  - COST Action CA15133
C3  - Book of abstracts: 4th FeSBioNet Meeting: COST Action CA15133; 2019 Sep 16-19; Gdansk, Poland
T1  - Structure of biliverdin and its interaction with copper
EP  - 44
SP  - 44
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_3187
ER  - 

@conference{
author = "Dimitrijević, Milena and Bogdanović Pristov, Jelena and Žižić, Milan and Stanković, Dalibor and Bajuk-Bogdanović, Danica and Stanić, Marina and Hagen, Wilfred and Piccioli, Mario and Spasojević, Ivan",
year = "2019",
abstract = "The structure of biliverdin (BV) and its complexion capacity with Cu2+ in dependence of
solvent choice has been examined. We first examined coordinate/redox interactions of BV
with Cu2+ in phosphate buffer at pH 7.4, using spectrophotometry, HESI-MS, Raman
spectroscopy, 1HNMR, EPR, fluorimetry, and electrochemical methods. BV formed a stable
coordination complex with copper in 1 : 1 stoichiometry. The structure of BV was more
planar and energetically stable in the complex. The complex showed strong paramagnetic
effects that were attributed to an unpaired delocalized e−. The delocalized electron may come
from BV or Cu2+, so the complex is formally composed either of BV radical cation and Cu1+
or of BV radical anion and Cu3+. The complex underwent oxidation only in the presence of
both O2 and an excess of Cu2+, or a strong oxidizing agent, and it was resistant to reducing
agents. The biological effects of the stable BV metallocomplex containing a delocalized
unpaired electron should be further examined, and may provide an answer to the longstanding
question of high energy investment in the catabolism of BV, which represents a
relatively harmless molecule per se. The complex possibility was quite different after
changing the solvent. BV structure in DMSO was analyzed by using NMR techniques and
unrestricted density function theory simulations to explain the incapacity of BV to build
coordination complex(es) with Cu2+ in dimethyl sulfoxide, which was confirmed by UV-Vis,
EPR and NMR spectroscopy. NMR showed that N atoms of BV are protonated in all four
pyrrole rings. The structure is stabilized by two hydrogen bonds between NH moieties and
carbonyl oxygens from opposite terminal pyrrole rings, and by the bending of propionyl chain
with carboxyl group out of the plain toward central position of BV. The simulations of
deprotonated BV, which builds copper complexes in water and chloroform as described
previously, showed a different conformation and organization of hydrogen bonds. Taking into
account that deprotonation represents a critical step in coordinate bonds formation, the
protonation of an additional N atom may represent a key difference between the interactions
of BV with copper in different solvents.",
publisher = "COST Action CA15133",
journal = "Book of abstracts: 4th FeSBioNet Meeting: COST Action CA15133; 2019 Sep 16-19; Gdansk, Poland",
title = "Structure of biliverdin and its interaction with copper",
pages = "44-44",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_3187"
}

Dimitrijević, M., Bogdanović Pristov, J., Žižić, M., Stanković, D., Bajuk-Bogdanović, D., Stanić, M., Hagen, W., Piccioli, M.,& Spasojević, I.. (2019). Structure of biliverdin and its interaction with copper. in Book of abstracts: 4th FeSBioNet Meeting: COST Action CA15133; 2019 Sep 16-19; Gdansk, Poland
COST Action CA15133., 44-44.
https://hdl.handle.net/21.15107/rcub_rimsi_3187

Dimitrijević M, Bogdanović Pristov J, Žižić M, Stanković D, Bajuk-Bogdanović D, Stanić M, Hagen W, Piccioli M, Spasojević I. Structure of biliverdin and its interaction with copper. in Book of abstracts: 4th FeSBioNet Meeting: COST Action CA15133; 2019 Sep 16-19; Gdansk, Poland. 2019;:44-44.
https://hdl.handle.net/21.15107/rcub_rimsi_3187 .

Dimitrijević, Milena, Bogdanović Pristov, Jelena, Žižić, Milan, Stanković, Dalibor, Bajuk-Bogdanović, Danica, Stanić, Marina, Hagen, Wilfred, Piccioli, Mario, Spasojević, Ivan, "Structure of biliverdin and its interaction with copper" in Book of abstracts: 4th FeSBioNet Meeting: COST Action CA15133; 2019 Sep 16-19; Gdansk, Poland (2019):44-44,
https://hdl.handle.net/21.15107/rcub_rimsi_3187 .

TY  - CONF
AU  - Korać Jačić, Jelena
AU  - Stanković, Dalibor
AU  - Bogdanović Pristov, Jelena
AU  - Nikolic, Ljiljana
AU  - Spasojević, Ivan
PY  - 2018
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2844
AB  - Epinephrine ((R)-4-(1-hydroxy-2-(methylamino)ethyl)-benzene-1,2-diol (Epi) is catecholamine that is released by the sympathetic nervous system and adrenal medulla. It is a physiologically important molecule that acts as a hormone, neurotransmitter, and medication with a broad range of effects 1-3 . Coordinate and redox interaction of Epi with iron affects the interactions with other molecules and its biological effects 4 . In this study, we reported details of redox interactions of Epi with Fe 2+ at pH 7.4, which correspond to the pH value of human plasma Epi and Fe 2+ form a complex that acts as a strong reducing agent. Cyclic voltammetry showed that the positions of E pa and E pc potentials were at approximately -480 and -1100 mV. This implies that Epi and Fe 2+ build a complex with unique redox properties. E1/2 was significantly lower compared to E0' for O 2 /O 2•- (-350 mV). It is important to point out this because superoxide radical anion is produced via spontaneous Fe 2+ reaction with O 2. In other words, Epi-Fe 2+ complex should be capable of reducing transition metals in (patho)physiologicaly relevant complexes that are not susceptible to reduction by O 2. Our results confirmed that Epi-Fe 2+ is capable of reducing the S-S group of glutathione disulfide. On the other hand, Epi acted in a catalyst-like fashion to promote Fe 2+ oxidation by molecular oxygen, and to a facilitated formation of the Epi–Fe 3+ complexes, at physiological pH. In addition, we examined the effects of epinepfrine and Epi/Fe3+ system on glioma cells. Epinephrine alone evokes changes in the membrane currents of glioma cells, but such effects were not observed for the complex with Fe 3+ . This implies that Epi-Fe 3+ might modulate neural activity of Epi in CNS.
PB  - Biohemijsko drustvo Srbije
C3  - Proceedings: Serbian Biochemical Society Eigth Conference with international participation: Coordination in Biochemistry and Life; 2018 Nov 16; Novi Sad, Serbia
T1  - Redox interactions of epinephrine with iron at physiological pH
EP  - 142
SP  - 141
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2844
ER  - 

@conference{
author = "Korać Jačić, Jelena and Stanković, Dalibor and Bogdanović Pristov, Jelena and Nikolic, Ljiljana and Spasojević, Ivan",
year = "2018",
abstract = "Epinephrine ((R)-4-(1-hydroxy-2-(methylamino)ethyl)-benzene-1,2-diol (Epi) is catecholamine that is released by the sympathetic nervous system and adrenal medulla. It is a physiologically important molecule that acts as a hormone, neurotransmitter, and medication with a broad range of effects 1-3 . Coordinate and redox interaction of Epi with iron affects the interactions with other molecules and its biological effects 4 . In this study, we reported details of redox interactions of Epi with Fe 2+ at pH 7.4, which correspond to the pH value of human plasma Epi and Fe 2+ form a complex that acts as a strong reducing agent. Cyclic voltammetry showed that the positions of E pa and E pc potentials were at approximately -480 and -1100 mV. This implies that Epi and Fe 2+ build a complex with unique redox properties. E1/2 was significantly lower compared to E0' for O 2 /O 2•- (-350 mV). It is important to point out this because superoxide radical anion is produced via spontaneous Fe 2+ reaction with O 2. In other words, Epi-Fe 2+ complex should be capable of reducing transition metals in (patho)physiologicaly relevant complexes that are not susceptible to reduction by O 2. Our results confirmed that Epi-Fe 2+ is capable of reducing the S-S group of glutathione disulfide. On the other hand, Epi acted in a catalyst-like fashion to promote Fe 2+ oxidation by molecular oxygen, and to a facilitated formation of the Epi–Fe 3+ complexes, at physiological pH. In addition, we examined the effects of epinepfrine and Epi/Fe3+ system on glioma cells. Epinephrine alone evokes changes in the membrane currents of glioma cells, but such effects were not observed for the complex with Fe 3+ . This implies that Epi-Fe 3+ might modulate neural activity of Epi in CNS.",
publisher = "Biohemijsko drustvo Srbije",
journal = "Proceedings: Serbian Biochemical Society Eigth Conference with international participation: Coordination in Biochemistry and Life; 2018 Nov 16; Novi Sad, Serbia",
title = "Redox interactions of epinephrine with iron at physiological pH",
pages = "142-141",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2844"
}

Korać Jačić, J., Stanković, D., Bogdanović Pristov, J., Nikolic, L.,& Spasojević, I.. (2018). Redox interactions of epinephrine with iron at physiological pH. in Proceedings: Serbian Biochemical Society Eigth Conference with international participation: Coordination in Biochemistry and Life; 2018 Nov 16; Novi Sad, Serbia
Biohemijsko drustvo Srbije., 141-142.
https://hdl.handle.net/21.15107/rcub_rimsi_2844

Korać Jačić J, Stanković D, Bogdanović Pristov J, Nikolic L, Spasojević I. Redox interactions of epinephrine with iron at physiological pH. in Proceedings: Serbian Biochemical Society Eigth Conference with international participation: Coordination in Biochemistry and Life; 2018 Nov 16; Novi Sad, Serbia. 2018;:141-142.
https://hdl.handle.net/21.15107/rcub_rimsi_2844 .

Korać Jačić, Jelena, Stanković, Dalibor, Bogdanović Pristov, Jelena, Nikolic, Ljiljana, Spasojević, Ivan, "Redox interactions of epinephrine with iron at physiological pH" in Proceedings: Serbian Biochemical Society Eigth Conference with international participation: Coordination in Biochemistry and Life; 2018 Nov 16; Novi Sad, Serbia (2018):141-142,
https://hdl.handle.net/21.15107/rcub_rimsi_2844 .