A protein model exhibiting three folding transitions

We explain the physical basis of a model for small globular proteins with water interactions. The water is supposed to access the protein interior in an "all-or-none" manner during the unfolding of the protein chain. As a consequence of this mechanism (somewhat speculative), the model exhibits fundamental aspects of protein thermodynamics, as cold, and warm unfolding of the polypeptide chain, and hence decreasing the temperature below the cold unfolding the protein folds again, accordingly the heat capacity has three characteristic peaks. The cold and warm unfolding has a sharpness close to a two-state system, while the cold folding is a transition where the intermediate states in the folding is energetical close to the folded/unfolded states, yielding a less sharp transition. The entropy of the protein chain causes both the cold folding and the warm unfolding.Comment: 13 pages LaTeX, 4 Postscript figure

SPECIFIC OF LOCAL GOVERNMENT PROCUREMENT MANAGEMENT IN GEORGIA

Procurement at the local self-government level in Georgia is carried out in accordance with the rules established by the Law of Georgia on State Procurement. In this case, the difference between local and state procurement is not observed at the concept level, the specifics of the municipalities are not considered anywhere. The main objectives of the Law on Public Procurement are to rationalize the funds allocated for procurement, as well as to ensure a fair and non-discriminatory approach to procurement during procurement. However, violations of the principle of justice still occur at the municipal level. Due to the fact that procurement procedures take quite a long time and also, our research has revealed a number of shortcomings related to administration, hindering the effective functioning of municipalities. JEL: H11; H70 Article visualizations

Electrostatic Contribution of Surface Charge Residues to the Stability of a Thermophilic Protein: Benchmarking Experimental and Predicted pKa Values

Optimization of the surface charges is a promising strategy for increasing thermostability of proteins. Electrostatic contribution of ionizable groups to the protein stability can be estimated from the differences between the pKa values in the folded and unfolded states of a protein. Using this pKa-shift approach, we experimentally measured the electrostatic contribution of all aspartate and glutamate residues to the stability of a thermophilic ribosomal protein L30e from Thermococcus celer. The pKa values in the unfolded state were found to be similar to model compound pKas. The pKa values in both the folded and unfolded states obtained at 298 and 333 K were similar, suggesting that electrostatic contribution of ionizable groups to the protein stability were insensitive to temperature changes. The experimental pKa values for the L30e protein in the folded state were used as a benchmark to test the robustness of pKa prediction by various computational methods such as H++, MCCE, MEAD, pKD, PropKa, and UHBD. Although the predicted pKa values were affected by crystal contacts that may alter the side-chain conformation of surface charged residues, most computational methods performed well, with correlation coefficients between experimental and calculated pKa values ranging from 0.49 to 0.91 (p<0.01). The changes in protein stability derived from the experimental pKa-shift approach correlate well (r = 0.81) with those obtained from stability measurements of charge-to-alanine substituted variants of the L30e protein. Our results demonstrate that the knowledge of the pKa values in the folded state provides sufficient rationale for the redesign of protein surface charges leading to improved protein stability

"Community policing" як новий підхід профілактики окремих видів насильницьких злочинів

Махатадзе К. Г. "Community policing" як новий підхід профілактики окремих видів насильницьких злочинів / К. Г. Махатадзе // Одеські юридичні читання : Матер. всеукр. наук.-практ. конфер. (м. Одеса, 10–11 листопада 2017 р.) / за ред. Г. О. Ульянової ; уклад.: О. В. Дикий, Ю. Д. Батан. – Одеса : Видавничий дім "Гельветика", 2017. – С. 290-293

Злочини, що посягають на життя і здоров’я людини шляхом бездіяльності: сучасний стан та тенденції

Махатадзе К. Г. Злочини, що посягають на життя і здоров’я людини шляхом бездіяльності: сучасний стан та тенденції / К. Г. Махатадзе // Правові та інституційні механізми забезпечення розвитку України в умовах європейської інтеграції : матеріали Міжнародної науково-практичної конференції (м. Одеса, 18 травня 2018 р.) У 2-х т. Т. 2 / відп. ред. Г.О. Ульянова. – Одеса : Видавничий дім «Гельветика», 2018. – С. 262-266

Exact Solution of the Munoz-Eaton Model for Protein Folding

A transfer-matrix formalism is introduced to evaluate exactly the partition function of the Munoz-Eaton model, relating the folding kinetics of proteins of known structure to their thermodynamics and topology. This technique can be used for a generic protein, for any choice of the energy and entropy parameters, and in principle allows the model to be used as a first tool to characterize the dynamics of a protein of known native state and equilibrium population. Applications to a $\beta$-hairpin and to protein CI-2, with comparisons to previous results, are also shown.Comment: 4 pages, 5 figures, RevTeX 4. To be published in Phys. Rev. Let

Роль Державного бюро розслідувань у протидії злочинів, передбачених статтями 135,136 КК України

Махатадзе К. Г. Роль Державного бюро розслідувань у протидії злочинів, передбачених статтями 135,136 КК України / К. Г. Махатадзе // Державне бюро розслідувань: на шляху розбудови : матер. Міжнар. наук.-практ. конф. (м. Одеса, 16 червня 2018 р.) / редкол.: Г. О. Ульянова (голова ред.), В. М. Дрьомін, Є. Л. Стрельцов [та ін.] ; НУ "ОЮА". - Одеса : Юридична література, 2018. - С. 410-412

Non-linearity of the collagen triple helix in solution and implications for collagen function

Collagen adopts a characteristic supercoiled triple helical conformation which requires a repeating (Xaa-Yaa-Gly)n sequence. Despite the abundance of collagen, a combined experimental and atomistic modelling approach has not so far quantitated the degree of flexibility seen experimentally in the solution structures of collagen triple helices. To address this question, we report an experimental study on the flexibility of varying lengths of collagen triple helical peptides, composed of six, eight, ten and twelve repeats of the most stable Pro-Hyp-Gly (POG) units. In addition, one unblocked peptide, (POG)10unblocked, was compared with the blocked (POG)10 as a control for the significance of end effects. Complementary analytical ultracentrifugation and synchrotron small angle X-ray scattering data showed that the conformations of the longer triple helical peptides were not well explained by a linear structure derived from crystallography. To interpret these data, molecular dynamics simulations were used to generate 50 000 physically realistic collagen structures for each of the helices. These structures were fitted against their respective scattering data to reveal the best fitting structures from this large ensemble of possible helix structures. This curve fitting confirmed a small degree of non-linearity to exist in these best fit triple helices, with the degree of bending approximated as 4–17° from linearity. Our results open the way for further studies of other collagen triple helices with different sequences and stabilities in order to clarify the role of molecular rigidity and flexibility in collagen extracellular and immune function and disease