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Metalotioneiny i motywy policysteinylowe : oddziaływanie z jonami metali

Krzywoszyńska K., Kozłowski H.

Wiadomości Chemiczne

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2018

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[Z] 72, 7-8

383--395

EN

Many of biochemical paths and processes require some metal ions to occur. There are also known the negative effects of the presence of metal ions in the organism. The both sides of metal ions interactions on the living organism require specific regulations and cannot be left without supervision and control of the organism itself. One of the strategy to keep the control on metal ions are cystein-rich proteins that play crucial role in detoxication of metal ions that are dangerous for human organism as well as they help to maintain homeostasis of essential metal ions. Matallothioneins are one of the well known, but still not fully understood, cysteine- rich proteins. They are small proteins but may contain up to 30% of cysteine residues in the sequence, and what makes them very special from chemical point of view - all of the thiols present there are reduced [1]. This property makes these proteins very tempting for coordination of various metal ions. The most efficient binding to metallothionein is observed for the ions belonging to a Group 11 and 12. Cu+, Zn2+ and Cd2+ represent these metal ions [2]. Besides of the lack of disulfide bridges, metallothioneins show also the absence or low amount of aromatic amino acid residues in the sequence [1]. Studies of the metallothioneins and their isoforms among different organisms show that the position of cysteine residues is very conservative [3]. Considering this aspect of metallothionein structure, some specific motifs of cysteine residues arrangement can be found in the sequence of these proteins. Most of the common polythiol motifs are CXC, CXXC, CXXXC, CC – where C is a cysteine residue and X is random α-amino acid residue (other than cysteine) [3–5]. The influence of the cysteine residues organization on the specificity of metal ions binding was intensively studied. The differences observed for specificity of metal ions binding by metallothioneins and selected polythiol motifs are reviewed in this paper – with strong emphasis on the effect of the cysteine residues topography.

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Polihistydylowe sekwencje z motywem His-tag – ich rola i biologiczne znaczenie oddziaływania z jonami metali

Wątły J., Kozłowski H.

Wiadomości Chemiczne

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2016

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[Z] 70, 11-12

1--24

EN

His-tags are specific sequences containing six to nine subsequent histydyl residues and they are used commercially in immobilized metal affinity chromatography (IMAC) as molecular ‘anchors’ that bind to a metal ion (usually nickel), immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support [37, 38]. Consecutive histidines are the common denominator for both His-tags used in molecular biology and for quite remote biological phenomena – more than 2000 histidine- rich proteins (HRPs) are found in microorganisms including 60% and 82% of archaeal and bacterial species, respectively and their roles are not well characterized [73]. The physicochemical properties of histidine make it a versatile amino acid that influences protein conformation and enzymatic activity [15]. Many natural proteins with a His-tag domain are assigned to different functions, for example: most bacterial proteins, containing this motif are probably involved in the homeostasis of nickel ions [68, 76], while others, e.g. newly isolated peptides from the venom of the snake genus Atheris contain poly-histidyl-poly-glycyl sequences (pHpG) can act on the cardiovascular system by inhibiting snake venom metalloproteinases and affect its function by acting on specific receptors [58, 62]. His-rich motifs have been found also e.g. in Zn2+ transporters, prion proteins, His-rich glycoproteins, transcription factors or numerous copper-binding proteins [56, 67, 84]. Binding mode and the thermodynamic properties of the system depends on the specific metal ion and the histidine sequence. Despite the wide application of the His-tag for purification of proteins, little is known about the properties of metalbinding to such tag domain. Recent experimental and theoretical studies have shown that metal ions, e.g. Cu2+ can bind to various sets of imidazoles depending on the number of histidine residues that are located in His-rich sequences. The occurrence of polymorphic binding states and the formation of an α-helical structure induced by metal ion coordination suggest that proteins with a His-tag domain may serve as the dynamic site able to ‘move’ metal ions along the tag sequence [99, 100]. This might explain the frequent occurrence of such sequences in bacterial Ni2+ chaperones, which transfer the metal ion between different proteins.

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Direct Liquid Chromatography with Photodiode and Fluorescence Detection for Simultaneous Quantification of Gonadotropin-Releasing Hormone (GnRH), Its Complex with Cu2+, and Catabolites

Michaluk A., Gajewska A., Kulon K., Kozłowski H., Kochman K., Kowalczyk J., Czauderna M.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 3

383-390

EN

Gonadotropin-releasing hormone (GnRH) and its complex with Cu2+(Cu-GnRH) were separated on a Nova Pak C18 column (4 m, 150 3.9 mm I.D., Wa ters). Analyses of underivatized GnRH and Cu-GnRH were per formed by a gradient elution program (HPLC method I), UV detection at 280 nm and fluorescence detection (gammexcitation = 280 nm/gammaemis sion = 360 nm). The mobile phases used were: acetonitrile with 0.08% trichloroacetic acid (w/w) and water with 0.1% trichloroacetic acid (w/w). Elutions were carried out in a binary gradient mode with a flow-rate of 1 mL/min and column temperature of 28°C. The proposed gradient elution program with UV and fluorescence detection allowed satisfactory fraction ation of GnRH (at 31.5 plus minus 0.2 min) from Cu-GnRH (at 30.3 plus-minus 0.2 min) and endogenous species present in samples of cytosol and subcellular organelles from the hypothalamus. The proposed reversed-phase HPLC method I with fluorescence detection provides a more sensitive analytical tool for routine and simultaneous quantification of GnRH, Cu-GnRH and their enzymatic degradation products (catabolites) in all biological samples as compared with HPLC method I with UV detection. To avoid problems due to overlap ping peaks corresponding to GnRH, Cu-GnRH, and the respective enzymatic degradation products in samples of cytosol and subcellular organelles from the hypothalamus, we propose a very shallow binary gradient elution program (method I). The separation efficiency of GnRH and Cu-GnRH peaks in standards and biological samples was assessed based on purity analysis of UV spectra (250-300 nm) and on the values of ratios of the fluorescence response to UV response at 280 nm. Our second reversed-phase liquid chromatographic method (HPLC method II) with pre-column derivatization of aminoacids in catabolites of GnRH and Cu-GnRH enabled investigations of the degradation pattern as well as of the yield of enzymatic degradation of GnRH and its Complex with Cu2+ in pituitary cytosol and sub-cellular organelles.

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Impact of Copper Ions on Chemistry and Biology of Prion Protein

Janicka A., Stańczak P., Kozłowski H.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 1

1-3

EN

The current state of art in the studies on Cu2+ ions interactions with mammalian and chicken prion protein (PrP) is discussed. The specificity of Cu2+ binding by tandem repeat domains of PrPs is actually well supported although themajor contradictions still exist as far as the fifth binding site is concerned. The biological relevance of Cu2+ coordination to octarepeat region of mammalian PrP seems to be generally accepted although the binding of the fifth metal ion may be just a chemical property of PrP.

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Modernizacja linii kolejowej E-20 na odcinku Mińsk Mazowiecki - Siedlce do prędkości V=160 km/h

Kozłowski H.

Wiadomości Projektanta Budownictwa

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2006

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nr 9

15--17

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Oxovanadium(IV) complexes of 1-hydroxyalkane-1,1-diyldiphosphonic acids

Dyba M., Kozłowski H., Tlałka A., Leroux Y., El Manouni D.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7

1148-1153

EN

Potentiometric and spectroscopic (EPR and UV-VIS) methods were used to study the oxovanadium(IV) complexation with several 1-hydroxyalkane-1,1-diyldiphosphonic acids. Coordination of oxovanadium(IV) to all diphosphonic ligands studied starts at very low pH and formation of the stable monomeric and trinuclear species between pH range 2-9 is observed.