	8.	Wypych A., Szpotkowski K., Jurga S., Domka L., Kozak M.
		Interactions of a cationic surfactant - (benzyloxymethyl) dodecyldimethylammonium chloride with model biomembrane systems Phospholipids are the main components of biological membranes. The aim of the present study was to determine the influence of a cationic surfactant on phospholipid structure and dynamics. Fourier transform infrared (FTIR) and dielectric relaxation (DRS) spectroscopies as well as small-angle Xray scattering (SAXS) with synchrotron radiation have been used to analyse the structure of fully hydrated 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) in the presence of a quaternary ammonium surfactant: (benzyloxymethyl) dodecyldimethylammoniumchloride (BzMDDAC). The presence of the surfactant caused changes in the temperature of the DMPC phase transition, as revealed using FTIR and DRS measurements. This change results from the disappearance of the multilamellar phase of DMPC and the formation of the unilamellar (most likely bicellar) phase, as indicated by the SAXS results. (C) 2013 Elsevier B.V. All rights reserved.
		Colloids and Surfaces B: Biointerfaces, 108, 212-218 (2013)
		DOI: 10.1016/j.colsurfb.2013.03.010 (Pobrane: 2021-01-20)

	7.	Saini R., Szpotkowski K., Kozak M., Jaskolski M., Davis S.J.
		Biochemical and structural studies of plant circadian clock proteins Circadian clocks are biochemical oscillatory mechanisms that co-ordinate with a 24h period predicting the daily diurnal changes in the environment to regulate various metabolic, developmental and physiological processes in the organisms. The plant circadian clock represents a network of interconnected multiple feedback loops at the core of which lie two Myb-like transcription factors, Circadian Clock Associated 1 (CCA1) and Late Elongated Hypocotyl (LHY), that express in the morning, and an evening expressing Timing of CAB Expression 1 (TOC1). Other components important for the clock are Early Flowering 3 and 4 (ELF3 and ELF4) and Lux Arrhythmo (LUX) that accumulate in the evening (Harmer, 2009). Previous studies have shown these to be part of an evening complex that is important for the regulation of the core oscillator (Nusinow et al., 2011; Herrero et al., 2012). Loss-of-function mutation studies of these components demonstrate arrhythmia under constant conditions of light (LL) and in darkness (DD) (Kolmos et al., 2009; Thines and Harmon, 2010). Recently, it has been shown (both in vivo and in vitro) that ELF3 and ELF4 interact physically with each other to perform their regulatory function (Herrero et al., 2012). Here, using various in silico and experimental approaches, we have tried to understand the structural aspects of these two evening expressing plant clock proteins (ELF3 and 4). Due to the instability of the ELF4 and ELF3 proteins, crystallization and Small Angle X-ray Scattering (SAXS) measurements were carried out for recombinant variants tagged with fusion (MBP or NusA) proteins.
		Biotechnologia, 94(1), 40-41 (2013)
		DOI: 10.5114/bta.2013.46435 (Pobrane: 2020-10-23)

	6.	Makrocka-Rydzyk M., Wypych A., Szpotkowski K., Kozak M., Jurga S., Gao H.F., Cho H.Y., Matyjaszewski K.
		Structural studies of poly(butyl acrylate) - poly(ethylene oxide) miktoarm star polymers Structural behavior of miktoarm star polymers comprising poly(butyl acrylate) (PBA) and poly(ethylene oxide) (PEO) arms was studied by means of Differential Scanning Calorimetry (DSC), Wide Angle X-Ray Scattering (WAXS), Polarized Optical Microscopy (POM) and Fourier Transform Infrared Spectroscopy (FTIR) methods. The aim of this study was to correlate changes in the composition of the arms of the PBA/PEO miktoarm star polymers with their structures. As a consequence of increasing PBA content, the decrease in crystallinity of the studied PBA/PEO heteroarm star copolymers was observed. Regardless of the copolymer composition, fraction of oxyethylene units in the crystalline PEO phase was similar in all investigated systems. The POM images showed spherulitic morphology of the materials having low PBA content, while an increase in PBA arms fraction leads to the formation of less ordered structures. The analysis of FTIR vibrational spectrum indicates helical conformation of PEO chains in the crystalline phase. Isothermal crystallization studies carried out using the FTIR technique suggest the existence of isolated domains in the nanoscopic scale of investigated materials.
		Polymer, 52(24), 5513-5520 (2011)
		DOI: 10.1016/j.polymer.2011.09.020 (Pobrane: 2020-10-23)

	5.	Kozak M., Wypych A., Szpotkowski K., Jurga S., Skrzypczak A.
		Structural and spectroscopic studies of DMPC/cationic surfactant system Aqueous suspension of a mixture of 1,2-dimyrilstoyl-sn-glycero-3-phosphocholine (DMPC) and (dodecyloxymethyl)dodecydimethylammonium (DDMDDAC) has been investigated by Fourier transform infrared spectroscopy (FTIR), small angle scattering of synchrotron radiation (SAXS) and dielectric spectroscopy (DS). The introduction of surfactant to DMPC water solution probably induces formation of discoidal (bicellar) phase, as revealed by SAXS studies. The presence of the surfactant has been found to decrease the main phase transition temperature, i.e., from rippled gel to liquid crystalline phase, as indicated by the DS and FTIR results. The small steps in the real part of dielectric permittivity plot vs. temperature can be related to the: planar gel to rippled gel (L(beta') -> P(beta')) and rippled gel-liquid crystal (P(beta') -> L(alpha)) phase transitions, which is supported by the temperature dependencies of the symmetric and anti-symmetric CH(2) band frequencies from FTIR measurements. (C) 2010 Elsevier B.V. All rights reserved.
		Journal of Non-Crystalline Solids, 356(11-17), 747-753 (2010)
		DOI: 10.1016/j.jnoncrysol.2009.07.043

	4.	Kozak M., Szpotkowski K., Kozak A., Zieliński R., Wieczorek D., Gajda M.J., Domka L.
		The FTIR and SAXS studies of influence of a morpholine derivatives on the DMPC-based biological membrane systems Fourier transformed infrared (FTIR) spectroscopy and small-angle scattering of synchrotron radiation have been used to analyze the influence of two zwitterionic surfactants of the sulfobetaine structure (3-(N-decylmorpholine)-1-propansulfonate and 3-(N-tetradecylmorpholine)-1-propansulfonate) on the conformational dynamics of CH2 and O-P-O groups of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the structure of phospholipid bilayers. The presence of the surfactant causes changes in the DMPC phase transition temperature. Our small-angle X-ray scattering (SAXS) data analysis implies a gradual disappearance of the lamellar phase typical of DMPC and a probable formation of the bicellar phase or cubic phase in DMPC/surfactants system. (C) 2009 Elsevier Ltd. All rights reserved.
		Radiation Physics and Chemistry, 78(10), S129-S133 (2009)
		DOI: 10.1016/j.radphyschem.2009.03.090

	3.	Kozak M., Szpotkowski K., Kozak A., Zieliński R., Wieczorek D., Gajda M.J.
		The effect of selected zwitterionic surfactant on the structure of hydrated DMPC Differential scanning calorimetry, Fourier transformed infrared (FTIR) spectroscopy and small angle scattering of synchrotron radiation have been used to analyse the influence of zwitterionic surfactant (3-(N-hexylmorpholine)-1-propansulfonate) on the conformational dynamics of CH(2) and CH(3) groups of 1,2-dimyrilstoyl-sn-glycero-3-phosphocholine (DMPC) and the phase behaviour of phospholipid bilayers. The surfactant causes changes in the DMPC phase transition temperature and promotes a gradual disappearance of the lamellar phase of DMPC and a probable formation of the bicellar phase. (C) 2009 Elsevier Ltd. All rights reserved.
		Radiation Physics and Chemistry, 78(10), S112-S115 (2009)
		DOI: 10.1016/j.radphyschem.2009.04.029

	2.	Szpotkowski K., Kozak M., Kozak A., Zieliński R., Wieczorek D., Jurga S.
		Structural studies of selected DSPC-surfactant model systems of biological membranes Fourier transform infrared spectroscopy was used to analyse the influence of a cationic surfactant from the group of morpholine derivatives on the conformational dynamics of CH2 group in acyl chain of DSPC. The presence of the surfactant causes a decrease in the DSPC phase transition temperature. This result suggests that the surfactant interactions with phospholipid molecules disturb the lipid layers. The Fourier transform infrared measurements were supplemented with tests of the environmental toxicity of the surfactant used.
		Acta Physica Polonica A , 115(2), 561-564 (2009)
		DOI: 10.12693/APhysPolA.115.561 WWW: http://przyrbwn.icm.edu.pl/APP/PDF/115/a115z225.pdf (Pobrane: 2021-01-10)

	1.	Kozak M., Kempka M., Szpotkowski K., Jurga S.
		NMR in soft materials: A study of DMPC/DHPC bicellar system The DMPC/DHPC bicellar system at the molar ratio of 2.8:1 has been characterised by measurements of self-diffusion coefficient (using PFGSE and PFGSTE NMR sequences), differential scanning calorimetry (DSC) and small angle scattering of synchrotron radiation (SAXS). The DSC curve shows only one endothermic peak characterised by the peak temperature T-peak = 295.7 K and the onset temperature T-onset = 290.1 K. This peak can be assigned to the nematic to smectic phase transition. Below the phase transition temperature, NMR diffusion experiments indicate a two-exponential decay of the spin echo amplitude allowing two diffusion coefficients D, and D-2 to be extracted from the experimental data. The maximum size (D-max) of the bicelle determined from SAXS data using the pair distance distribution function p(r) is 11.2 nm and the bilayer thickness is 5 nm. (C) 2007 Published by Elsevier B.V.
		Journal of Non-Crystalline Solids, 353(47-51), 4246-4251 (2007)
		DOI: 10.1016/j.jnoncrysol.2007.02.068 (Pobrane: 2020-10-21)

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