XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
78
T2: O–10
Characterization of diamminedichloroplatinum(II) complexes
with DNA and serum albumins using FTIR spectroscopy
Veronika Travkina
1
, Irina Belaya
1
, Anastasia Batalova
1
, Elena Chikhirzhina
2
,
and Alexander Polyanichko
1,2
1
Department of Molecular Biophysics and Polymer Physics, Saint Petersburg State University, 7-9
Universitetskaya nab, Saint-Petersburg, 199034, Russian Federation,
e-mail: travkinaveronika@gmail.com
2
Laboratory of Molecular Biology of Stem Cells, Institute of Cytology of the Russian Academy of
Sciences, 4 Tikhoretsky Ave., 194064, Saint-Petersburg, Russian Federation
Treatment of cancer tumors is currently one of the most challenging tasks. There are several
antitumor drugs based on platinum coordination compounds, which are successfully used in
medical practice. One of the most known and widespread drug of this kind is
diamminedichloroplatinum(II) (DDP). The biological activity of the compound arises from its
ability to interact with DNA and proteins in living cell. However, many aspects of the molecular
mechanisms of the biological activity of such compounds remain unclear. Our present study is
primarily devoted to the investigation of the influence of cis- and trans- isomers of DDP on the
structure of DNA and serum albumins.
We have studied complexes of DNA and serum albumins (SA) with cis- and trans- DDP
using Fourier transform infrared spectroscopy (FTIR). The application of FTIR spectroscopy
allowed us to study the DDP/DNA and DDP/SA complexes in D2O solutions using DNA and
protein concentrations close to their physiological levels. To analyze FTIR spectra in the amide I
region we have decomposed the absorption band with Gaussian profiles positioned according to
the minima of the second derivative of the spectrum. Based on the data obtained we conclude
that both of the DDP isomers facilitate the formation of BSA dimers. The observed effect is
stronger for the trans-DDP, than for the cis- isomer.
We have also investigated the interaction between DDP isomers and DNA using FTIR
spectroscopy. To analyze the spectral data we have applied the above approach. As a result, we
have shown that cis- and trans- DDP predominantly interact with purines. We have also found
that binding of cis-DDP considerably changes the geometry of the sugar-phosphate backbone,
while DNA remains within the limits of B-conformation.
Keywords: DDP; FTIR spectroscopy
Acknowledgment
Part of the study was carried out in the Center for Optical and Laser Materials Research and Center for
Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics of St. Petersburg
State University. The work was supported by Russian Foundation for Basic Research (RFBR, grant 15-08-
06876).
XIV
h
International Conference on Molecular Spectroscopy, Białka Tatrzańska 2017
79
T2: O–11
Resonance Raman spectra of diacids of octaalkylporphyrins
Alexander Starukhin
1
, Michał Kijak
2
, Aleksander Gorski
2
, S. Gawinkowski
2
,
and Solomon Stavrov
3
1
B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Independence Av. 68,
220072, Minsk, Belarus, e-mail: a.starukhin@ifanbel.bas-net.by
2
Institute
of
Physical Chemistry,
Polish
Academy
of
Sciences,
Kasprzaka
44/52,
01-224
Warsaw,
Poland
3
Sackler Institute of Molecular Medicine, Department of Human Molecular Genetics and
Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
It is well known that metal-incorporation reactions (i.e. syntheses of metalloporphyrins) require
acidic conditions and that the porphyrin diacids may play an important role in the chemical synthesis
of such metallocomplexes. In acidic conditions the free-base porphyrins are transformed to N-
protonated diacids and their photophysical parameters drastically change in comparison to their
neutral forms. The protonation leads to the formation of nonplanar macrocycles, as results of the
steric hindrance and electrostatic repulsion of the central hydrogen atoms.
In this report we present results of the study of acidic forms of 2,3,7,8,12,13,17,18-
octamethylporphyrin (H
4
OMP
2+
), as well as H
4
OMP
2+
with hydrogen atoms in meso-position
exchanged by atoms of deuterium (H
4
OMP
2+
-d
4
) and 2,3,7,8,12,13,17,18-octaethylporphyrin
(H
4
OEP
2+
), by method of Raman microscopy in a crystal powder. The methodology of sample
preparation and the experimental setup have been described in details previously [1]. The frequencies
of normal modes and their Raman activities were simulated by means of DFT methods and compared
with the experimental results. All spectra recorded for diacids were compared with Raman data of
their parent neutral forms.
Fig. 1. Raman spectra of H
2
OMP (black) and its diacid form H
4
OMP
2+
(blue) obtained by 514.5 nm excitation.
The formation of diacid species, with four hydrogen atoms in the centre of the porphyrin
macrocycle, leads to significant changes in the Raman spectrum of H2OMP (see Fig. 1). The set of
new intense lines with frequencies of 248, 283, 333, 662, 680, 697, 753, 860 and 879 сm
−1
manifests
itself in the spectral range below 900 cm
−1
. It is explained by the saddle type distortion of the
macrocycle upon protonation, induced by the crowding effect provided by two additional inner
protons, as well as by the electrostatic repulsion between them. The interaction with the two
counterions placed on the opposite sides of the molecule cannot be also neglected and its influence on
the Raman spectrum will be analyzed by quantum-chemical modeling.
Keywords: diacids of octaalkylporphyrins; Raman microscopy; out-of-plane modes
Acknowledgment
This work was supported by the European Union’s Horizon 2020 research and innovation program under grant
agreement No 645628 and Foundation for Fundamental Research of Republic of Belarus (project Ph16R-084).
References
[1] A. Gorski, A. Starukhin, S. Stavrov, S. Gawinkowski, J. Waluk, Spectrochim. Acta A 173 (2017) 350.
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