Adenine and guanine recognition of stop codon is mediated by different N domain conformations of translation termination factor eRF1

Positioning of release factor eRF1 toward adenines and the ribose-phosphate backbone of the UAAA stop signal in the ribosomal decoding site was studied using messenger RNA (mRNA) analogs containing stop signal UAA/UAAA and a photoactivatable cross-linker at definite locations. The human eRF1 peptides cross-linked to these analogs were identified. Cross-linkers on the adenines at the 2nd, 3rd or 4th position modified eRF1 near the conserved YxCxxxF loop (positions 125–131 in the N domain), but cross-linker at the 4th position mainly modified the tripeptide 26-AAR-28. This tripeptide cross-linked also with derivatized 3′-phosphate of UAA, while the same cross-linker at the 3′-phosphate of UAAA modified both the 26–28 and 67–73 fragments. A comparison of the results with those obtained earlier with mRNA analogs bearing a similar cross-linker at the guanines indicates that positioning of eRF1 toward adenines and guanines of stop signals in the 80S termination complex is different. Molecular modeling of eRF1 in the 80S termination complex showed that eRF1 fragments neighboring guanines and adenines of stop signals are compatible with different N domain conformations of eRF1. These conformations vary by positioning of stop signal purines toward the universally conserved dipeptide 31-GT-32, which neighbors guanines but is oriented more distantly from adenines

Supersymmetric QCD corrections to e+e−→tbˉH−e^+e^-\to t\bar{b}H^- and the Bernstein-Tkachov method of loop integration

The discovery of charged Higgs bosons is of particular importance, since their existence is predicted by supersymmetry and they are absent in the Standard Model (SM). If the charged Higgs bosons are too heavy to be produced in pairs at future linear colliders, single production associated with a top and a bottom quark is enhanced in parts of the parameter space. We present the next-to-leading-order calculation in supersymmetric QCD within the minimal supersymmetric SM (MSSM), completing a previous calculation of the SM-QCD corrections. In addition to the usual approach to perform the loop integration analytically, we apply a numerical approach based on the Bernstein-Tkachov theorem. In this framework, we avoid some of the generic problems connected with the analytical method.Comment: 14 pages, 6 figures, accepted for publication in Phys. Rev.

Клиническая эффективность и безопасность применения ингаляционного простациклина у больных с инфекцией, вызванной SARS-CoV-2 (проспективное сравнительное исследование)

Aim. In this study we evaluated clinical effectiveness and safety of nebulized prostacyclin in patients with Novel Coronavirus Disease (SARS-CoV-2). Materials and methods: We have included 44 male patients with moderate PCR confirmed SARS-CoV-2 infection in this study. Control group consisted of 23 patients treated with nebulized prostacyclin (PGI2). besides standard therapy. We compared intensiveness and duration of infectious intoxication syndrome, duration of fever, cough as well as SpO2 level, complete blood count and chemokine status values. Results: Statistically significant difference in duration of fever, cough, intensiveness and duration of infectious intoxication syndrome were observed. Lymphocyte and platelet counts were significantly higher in control group We have also noticed significantly lower level of proinflammatory mediators and C4-complement component in control group. Only 1 adverse effect associated with inhaled prostacyclin was reported. Conclusion. Nebulized prostacyclin showed therapeutic efficacy and good safety profile in adults with moderate COVID-19.Цель: оценка клинической эффективности и безопасность ингаляционного простациклина у пациентов с новой коронавирусной инфекцией (SARS-CoV-2). Материалы и методы: в исследование были включены 44 пациента мужского пола с подтвержденной новой коронавирусной инфекцией среднетяжелого течения. Опытную группу составили 23 пациента, которым, помимо стандартной терапии, был назначен ингаляционный простациклин (PGI2). Клиническая эффективность илопроста была оценена по длительности и выраженности общеинфекционных синдромов (интоксикации, лихорадки), длительности кашля, уровню насыщения крови кислородом, значениям параметров общеклинического анализа крови, показателю иммунологического статуса пациентов. Результаты: получено статистически значимое снижение длительности лихорадки, продолжительности кашля, выраженности и длительности синдрома общей инфекционной интоксикации в опытной группе. Также отмечено, что у этих пациентов средние значения количества лимфоцитов, тромбоцитов достоверно увеличивалось, а значение СОЭ снижалось. Средние значения провоспалительных цитокинов, хемокинов, а также С4-компонента комплемента были статистически значимо ниже, чем у больных COVID-19 в группе сравнения. Нежелательные реакции, связанные с инга ляционной терапией простациклином, были отмечены в 1 наблюдении. Заключение: показана терапевтическая эффективность и хороший профиль безопасности ингаляционного простациклина у пациентов с COVID-19 средней степени тяжести

[The environment of tRNA 3'-terminus in 80S ribosome A and P sites]

International audienceThe environment of tRNA 3'-terminus in the 80S ribosomal A and P sites was studied with a tRNA(Asp) analogue that bears a 4-thiouridine residue (s4U) attached to the 3'-terminal adenosine. The tRNA(Asp) analogue was obtained by in vitro T7 transcription followed by crosslinking with [32P]ps4Up and removal of the 3'-terminal phosphate. It was shown that the presence of the additional nucleotide at the 3'-end does not to hinder the codon-dependent binding of the tRNA to the A and P sites of 80S ribosome. Mild UV-irradiation of the ribosomal complexes containing a short appropriately designed mRNA and the tRNA analogue resulted in crosslinking of the analogue exclusively to 28S rRNA. The crosslinking was completely dependent on the presence of s4U in the tRNA analogue. Using hydrolysis of the crosslinked 28S rRNA with RNase H in the presence of deoxyoligomers complementary to various rRNA sequences, we determined that the crosslinking occurred in fragment 4302-4540 of the 28S rRNA. This fragment is evolutionarily conservative and belongs to domain V that is involved in the formation of the peptidyl transferase site in prokaryotic ribosomes. The use of reverse transcription allowed the determination of the tRNA analogue crosslinking in the P site to nucleotides U4461 and U4502, and the analogue in the A site, to nucleotides U4469 and C4507. In addition, nucleotide C4462 was crosslinked to both P site and A site-bound tRNA analogue. An analysis of the results demonstrates that environments of the tRNA 3'-termini are closely similar in both prokaryotic and eukaryotic ribosomes