New reactive DNA probes for fishing out of DNA-binding proteins

Group of Assoc. Prof. Hocek developed new very reactive modified DNA probes suitable for selective fishing out of proteins binding to the particular DNA sequence. They prepared DNA bearing reactive chemical groups (vinylsulfonamides) that can very easily (under physiological conditions) attach other molecules bearing thiol groups, i.e. proteins containing amino acid cysteine. The methodology has been tested on bioconjugation of DNA probes with protein p53, which is an important tumour suppressor. The methodology has a promising potential for applications in analysis and identification of sequence-specific DNA-binding proteins that may play key roles in biological processes (i.e. regulation of gene expression) and in development of irreversible inhibitors of some oncogenic factors for antitumor therapy.

Significant results 2013-1

Dadová J., Orság P., Pohl R., Brázdová M., Fojta M., Hocek M.:
Vinylsulfonamide and acrylamide modification of DNA for cross-linking with proteins.
Angewandte Chemie International Edition 52: 10515-10518, 2013.

The first demostration of the interaction of insulin with insulin receptor

Deffects in insulin secretion or signaling cause serious disease, diabetes mellitus. The action of insulin is mediated by its binding to a specific cell receptor. The effort of four international teams resulted in the preparation and analysis of crystals of a complex of insulin with insulin receptor and in the first detailed view of the interaction of both molecules. The sciencists from IOCB contributed by a development of highly active insulin analogs. The elucidation of insulin-receptor interaction may assist in the development of more effective therapies for treating diabetes.

Significant results 2013-2

Interaction of insulin with site 1 of insulin receptor. Crystal structure of a complex of insulin with L1, CR and CT domains of insulin receptor. Insulin A chain is blue and insulin B chain is yellow.

Menting J.G., Whittaker J., Margetts M.B., Whittaker L.J., Kong G.K.W., Smith B.J., Watson C.J., Žáková L., Kletvíková K., Jiráček J., Jin Chan S.J., Steiner D.F., Dodson G.G., Brzozowski A.M., Weiss M.A., Ward, C.W., Lawrence M.C.:
How insulin engages its primary binding site on the insulin receptor.
Nature 493: 241-245, 2013.

Žáková L., Kletvíková E., Veverka V., Lepšík M., Watson, C.J., Turkenburg J.P., Jiráček J., Brzozowski A.M.:
Structural integrity of the B24 site in human insulin is important for hormone functionality.
Journal of Biological Chemistry 288: 10230-1040, 2013.

Alkylation of gold surfaces with an alkyl-carrying organometallic

The two papers on the alkylation of gold surfaces with an alkyl-carrying organometallic (Figure 1) document the first successful direct coating of gold with alkyls without the intermediacy of another element, such as sulfur. Their potential technological significanceis documented not only by the participation of SONY scientists in the reseach but also by the willingness of the SONY company to make a financial investment into gaining patent protection for the new concept (the patent will be issued next month). These papers also underlie our successful application for a GACR grant that has just been approved.

Significant results 2013-3

Formation of self-assembled monolayer by treatment of gold surface with n-butylmercury tosylate.

Mucha M., Kaletová E., Kohutová A., Scholz F., Stensrud E.S., Stibor I., Pospíšil L., von Wrochem F., Michl J.:
Alkylation of Gold Surface by Treatment with C18H37HgOTs and Anodic Hg Stripping.
Journal of the American Chemical Society 135: 5669-5677, 2013.

Scholz F., Kaletová E., Stensrud E.S., Ford W.E., Kohutová A., Mucha M., Stibor I., Michl J., von Wrochem F.:
Formation of n-Alkyl Mono Layers by Organomercury Deposition on Gold.
Journal of Physical Chemistry Letters 4: 2624-2629, 2013.

Carborane-based carbonic anhydrase inhibitors

Carbonic anhydrases are enzymes with important role in numerous physiological and patophysiological processes. Carbonic anhydrase IX (CAIX) is overexpressed on the cell surface in solid tumors and serves thus as a diagnostic marker and a target of anti-cancer drugs. Based on detailed structural analysis, compounds based on carborane clusters were designed and synthesized. These inhibitors specifically inhibit CAIX and not other physiologically important CA enzymes, such as CAII.

Significant results 2013-4

Crystal structure of CAII in complex with 4a (a) or 7a (b). The protein is shown as ribbon diagram; residues involved in interactions are shown as stick representations. Polar interactions are represented by dashed blue lines; Zn2+ ion coordination is represented by dashed black lines. The binding mode of 1a (black line) is superimposed on the crystal structures.

Brynda J., Mader P., Šícha V., Fábry M., Poncová K., Bakardiev M., Grüner B., Cígler P., Řezáčová P.:
Carborane-based carbonic anhydrase inhibitors.
Angewandte Chemie International Edition 52: 13760-13763, 2013.

Nail to the coffin of "scientific" justifications of homeopathy

What is the influence of dissolved species, such as salt ions, on the structure and dynamics of water? Is their action short-ranged or long-ranged? And is the behavior of dissolved molecules or ions in water cooperative of not? The latest Czech-French study based on computer simulations and analytical models provides detailed answers to these questions. It shows that the impact of ions is short-ranged and does not extend beyond their immediate hydration layer. As a result, in diluted solutions cations and anions behave practically independently of each other and no long-ranged cooperative effects can be observed. Only in concentrated solutions, where hydration layers of individual ions start to overlap a simple additive model ceases to be valid, which leads among others to non-linear changes in viscosity. Predictions of this theoretical study are not only in an excellent agreement with results of spectroscopic measurements, but also point to untenability of ideas about long-ranged effects in space and time of dissolved species in diluted solutions as employed, e. g., in "scientific" justifications of homeopathy.

Significant results 2013-5

Stirnemann G., Wernersson E., Jungwirth P., Laage D.:
Mechanisms of Acceleration and Retardation of Water Dynamics by Ions.
Journal of the American Chemical Society 135: 11824-11831, 2013.