Mechanism of Translation Inhibition by Type II GNAT Toxin AtaT2

Type II toxin-antitoxins systems are widespread in prokaryotic genomes. Typically, they comprise two proteins, a toxin, and an antitoxin, encoded by adjacent genes and forming a complex in which the enzymatic activity of the toxin is inhibited. Under stress conditions, the antitoxin is degraded liberating the active toxin. Though thousands of various toxin-antitoxins pairs have been predicted bioinformatically, only a handful has been thoroughly characterized. Here, we describe the AtaT2 toxin from a toxin-antitoxin system from Escherichia coli O157:H7. We show that AtaT2 is the first GNAT (Gcn5-related N-acetyltransferase) toxin that specifically targets charged glycyl tRNA. In vivo, the AtaT2 activity induces ribosome stalling at all four glycyl codons but does not evoke a stringent response. In vitro, AtaT2 acetylates the aminoacyl moiety of isoaccepting glycyl tRNAs, thus precluding their participation in translation. Our study broadens the known target specificity of GNAT toxins beyond the earlier described isoleucine and formyl methionine tRNAs, and suggest that various GNAT toxins may have evolved to specifically target other if not all individual aminoacyl tRNAs

YB-1 promotes microtubule assembly in vitro through interaction with tubulin and microtubules

<p>Abstract</p> <p>Background</p> <p>YB-1 is a major regulator of gene expression in eukaryotic cells. In addition to its role in transcription, YB-1 plays a key role in translation and stabilization of mRNAs.</p> <p>Results</p> <p>We show here that YB-1 interacts with tubulin and microtubules and stimulates microtubule assembly <it>in vitro</it>. High resolution imaging via electron and atomic force microscopy revealed that microtubules assembled in the presence of YB-1 exhibited a normal single wall ultrastructure and indicated that YB-1 most probably coats the outer microtubule wall. Furthermore, we found that YB-1 also promotes the assembly of MAPs-tubulin and subtilisin-treated tubulin. Finally, we demonstrated that tubulin interferes with RNA:YB-1 complexes.</p> <p>Conclusion</p> <p>These results suggest that YB-1 may regulate microtubule assembly <it>in vivo </it>and that its interaction with tubulin may contribute to the control of mRNA translation.</p

Changing fortunes and attitudes: what determines the political trust in modern Russia?

Research background: We are guided by concepts linking political trust with the perceived rank of people in the wealth hierarchy, their confidence in other people, and the means they use to learn about events at home and abroad. Purpose of the article: The aim of the article is to assess and analyse at the micro level the impact of subjective welfare, interpersonal trust and the intensity of usage of television &amp; radio or the Internet to search for news on political trust in four levels of Russian government. Methods: The study is based on microdata from the Life in Transition Surveys provided by the European Bank for Reconstruction and Development. Ordinal logit regressions are constructed to evaluate the impact of test and control variables on political trust in the Russian president, federal, regional, and local governments in 2010 and 2016. Findings &amp; value added: We identify a reverse of political trust in the upper levels of the Russian government between 2010 and 2016, when the impact of perceived welfare level changes from positive to negative. This phenomenon is explained by the focus of the policy of the federal centre on sup-porting the poor groups of the population, as well as its distancing from business. In contrast, the positive, albeit inconsistent, effect of subjective wealth on trust in lower-level governments is due to the benefits that businesses can gain from interaction with local authorities. We find the positive impact of controlled television and radio on trust in the upper echelons of power, along with the negative impact of the freer Internet on political trust in regional and local authorities. We also confirm the hypothesis of a positive and significant relationship between interpersonal and political trust, highlighting the role of social capital. Finally, our research shows that in systems of the hierarchical type, such as Russia, specific mechanisms for maintaining political trust are established. They are associated with the redistribution of public expectations and claims to different branches of government. The results obtained are applicable for managing political trust through building a democratic state and civil society

Rotation influence on heat transfer at supersonic flow around a blunted body

Results of a numerical study of the supersonic high-enthalpy flow over a spherically blunt cone taking into account complicating factors are presented. These factors include simultaneous action of rotation of the body around the longitudinal axis and processes in ablating heat shield. The problem of body heating in a conjugate formulation is solved. At a nonzero angle of attack influence of an aircraft rotation with a small angular velocity (0–500 deg/s) on surface temperature distribution and heat and mass transfer is considered. The asymmetries of surface temperature and material removal via ablation on a rotating body were studied

Numerical study of the influence of spherically blunted cone oscillations during a supersonic air flow around on the characteristics of conjugate heat and mass transfer

This work examines the action of the fluctuations of a body in a supersonic air flow on coupled heat and mass transfer in a heat-protection material in the presence of injected thermochemical destruction products and heat and mass transfer between the body and the incoming flow. The results of a numerical study of a spatial supersonic flow around a spherically blunted cone oscillating in the pitch plane are presented. The influence of the oscillations of a body with angular velocity of 0–100 deg/s on the surface temperature and heat transfer characteristics is considere

Influence of the rotation of a blunt-nose cone on the heat exchange in the supersonic flow over it at an angle of attack

Some methods of control over the thermal regimes realized in a supersonic flow past a conic body with a nose blunted over a sphere were numerically investigated with account of complicating factors. The solution of the problem on the heat and mass transfer in the boundary layer on the surface of this body in the conjugate formulation made it possible to estimate the influence of the nonisothermality of the surface of the body on the characteristics of the indicated transfer. The influence of the rotation of such a body made of composite materials on the heat exchange in the flow over it was determined

Influence of the rotation of a blunt-nose cone on the heat exchange in the supersonic flow over it at an angle of attack

Some methods of control over the thermal regimes realized in a supersonic flow past a conic body with a nose blunted over a sphere were numerically investigated with account of complicating factors. The solution of the problem on the heat and mass transfer in the boundary layer on the surface of this body in the conjugate formulation made it possible to estimate the influence of the nonisothermality of the surface of the body on the characteristics of the indicated transfer. The influence of the rotation of such a body made of composite materials on the heat exchange in the flow over it was determined

Rotation influence on heat transfer at supersonic flow around a blunted body

Results of a numerical study of the supersonic high-enthalpy flow over a spherically blunt cone taking into account complicating factors are presented. These factors include simultaneous action of rotation of the body around the longitudinal axis and processes in ablating heat shield. The problem of body heating in a conjugate formulation is solved. At a nonzero angle of attack influence of an aircraft rotation with a small angular velocity (0–500 deg/s) on surface temperature distribution and heat and mass transfer is considered. The asymmetries of surface temperature and material removal via ablation on a rotating body were studied

Numerical simulation of thermoelectronic thermal protection in the case of high enthalpy flow past a multilayer shell

A mathematical model of the process of unsteady conjugate heat transfer of a thermionic thermal protection system during supersonic air flow around a spherically-blunted cone is investigated Estimates of the effect of evaporation (emission) of electrons from the emitter surface on lowering the temperature of the composite shell of the thermoelectronic thermal protection are made. The influence of different angles of attack on heat transfer modes in the system of multielement thermionic thermal protection has been studied Qualitative agreement of calculated results with the known data has been found

Numerical analysis of heat transfer characteristics during radiative-convective heating of a spherically blunted cone

Numerical analysis of the process of unsteady heat transfer in a composite material under th