Post-transcriptional modifications of tRNA are made to structurally diversify tRNA. These modifications alter noncovalent interactions within the ribosomal machinery, resulting in phenotypic changes related to cell metabolism, growth, and virulence. MiaE is a carboxylate bridged, nonheme diiron monooxygenase, which catalyzes the O2-dependent hydroxylation of a hypermodified-tRNA nucleoside at position 37 (2-methylthio-N(6)-isopentenyl-adenosine(37)-tRNA) [designated ms(2)i(6)A37]. In this work, recombinant MiaE was cloned from Salmonella typhimurium , purified to homogeneity, and characterized by UV-visible and dual-mode X-band EPR spectroscopy for comparison to other nonheme diiron enzymes. Additionally, three nucleoside substrate-surrogates (i(6)A, Cl(2)i(6)A, and ms(2)i(6)A) and their corresponding hydroxylated products (io(6)A, Cl(2)io(6)A, and ms(2)io(6)A) were synthesized to investigate the chemo- and stereospecificity of this enzyme. In the absence of the native electron transport chain, the peroxide-shunt was utilized to monitor the rate of substrate hydroxylation. Remarkably, regardless of the substrate (i(6)A, Cl(2)i(6)A, and ms(2)i(6)A) used in peroxide-shunt assays, hydroxylation of the terminal isopentenyl-C4-position was observed with >97% E-stereoselectivity. No other nonspecific hydroxylation products were observed in enzymatic assays. Steady-state kinetic experiments also demonstrate that the initial rate of MiaE hydroxylation is highly influenced by the substituent at the C2-position of the nucleoside base (v0/[E] for ms(2)i(6)A > i(6)A > Cl(2)i(6)A). Indeed, the >3-fold rate enhancement exhibited by MiaE for the hydroxylation of the free ms(2)i(6)A nucleoside relative to i(6)A is consistent with previous whole cell assays reporting the ms(2)io(6)A and io(6)A product distribution within native tRNA-substrates. This observation suggests that the nucleoside C2-substituent is a key point of interaction regulating MiaE substrate specificity.
Aim To explore the relationships between inclusive leadership, empowering leadership, nurses' perceived psychological empowerment and nurses' innovation capacity. Background Innovation capacity is essential for nurses to adapt to the changing health care environment. However, the current knowledge of nurses' innovation capacity and its' relationships between inclusive leadership, empowering leadership and psychological empowerment, is limited. Methods A cross‐sectional survey using a convenience sample was conducted among 1355 nurses in 10 hospitals in Tianjin, China. The data were analysed by correlation analysis, univariate analysis and PROCESS macro. Results High inclusive leadership, empowering leadership and high psychological empowerment were associated with high innovation capacity. The total effect of inclusive leadership and empowering leadership on innovation capacity through psychological empowerment was significant, with their indirect effects accounting for 69.19% and 61.29% of the total effect, respectively. Conclusions To cultivate nurses' innovation capacity, the development of inclusive leadership, empowering leadership and psychological empowerment is important. Implications for nursing management This research highlights the importance of inclusive leadership and empowering leadership to foster nurses' innovation capacity. Understanding the mediating role of psychological empowerment is expected to help nurse managers develop relevant intervention strategies to cultivate nurses' innovation capacity.
As the largest fatal disease in the world, coronary heart disease (CHD) not only seriously endangers human life and health, but also causes enormous economic burdens to individuals, health systems and countries around the world (Timmis et al., 2020;Virani et al., 2021).CHD affects 423 million people worldwide and accounts for 31% of deaths from CHD each year (Lum, McCreanor, Luo, & Graves, 2020).
Background The significance of spiritual care competence among nurses has been emphasized across countries and cultures in many studies. However, there were few studies on correlations among spiritual care competence, spiritual care perceptions, and spiritual health of nurses in China. Objective To investigate spiritual care competence, spiritual care perceptions, and spiritual health, and examine the correlations among spiritual care competence, spiritual care perceptions and spiritual health, and the mediating role of spiritual health between other two variables of Chinese nurses. Methods A cross-sectional and correlational design was implemented, and the STROBE Checklist was used to report the study. A convenience sample of 2,181 nurses were selected from 17 hospitals in 3 provinces, China. Participants provided data on sociodemographic by completing the Chinese Version of the Spiritual Care Competence Scale, the Chinese Version of the Spiritual Care-Giving Scale, and the Spiritual Health Scale Short Form. Descriptive statistics, univariate, multiple linear regression, and Pearson correlation analysis were used to analyze data. Results The total scores of spiritual care competence, spiritual care perceptions, and spiritual health were 58.25 ± 16.21, 144.49 ± 16.87, and 84.88 ± 10.57, respectively, which both were moderate. Spiritual care competence was positively correlated with spiritual care perceptions (r = 0.653, p < 0.01) and spiritual health (r = 0.587, p < 0.01). And spiritual health played a mediating role between the other two variables (accounting for 35.6%). Significance of results The spiritual care competence, spiritual care perceptions, and spiritual health of Chinese nurses need to be improved. It is recommended that nursing managers should pay attention to spiritual care education of nurses, and improve spiritual care perceptions and spiritual health in multiple ways, so as to improve their spiritual care competence and to maximize the satisfy spiritual care needs of patients in China.
MiaE [2-methylthio-N(6)-isopentenyl-adenosine(37)-tRNA monooxygenase] isolated from Salmonella typhimurium is a unique non-heme diiron enzyme that catalyzes the O2-dependent post-transcriptional allylic hydroxylation of a hypermodified nucleotide (ms(2)i(6)A37) at position 37 of selected tRNA molecules to produce 2-methylthio-N(6)-(4-hydroxyisopentenyl)-adenosine(37). In this work, isopentenylated tRNA substrates for MiaE were produced from small RNA oligomers corresponding to the anticodon stem loop (ACSL) region of tRNA(Trp) using recombinant MiaA and dimethylallyl pyrophosphate. Steady-state rates for MiaE-catalyzed substrate hydroxylation were determined using recombinant ferredoxin (Fd) and ferredoxin reductase (FdR) to provide a catalytic electron transport chain (ETC) using NADPH as the sole electron source. As with previously reported peroxide-shunt assays, steady-state product formation retains nearly stoichiometric (>98%) E stereoselectivity. MiaE-catalyzed i(6)A-ACSL(Trp) hydroxylation follows Michaelis-Menten saturation kinetics with kcat, KM, and V/K determined to be 0.10 ± 0.01 s(-1), 9.1 ± 1.5 μM, and ∼11000 M(-1) s(-1), respectively. While vastly slower, MiaE-catalyzed hydroxylation of free i(6)A nucleoside could also be observed using the (Fd/FdR)-ETC assay. By comparison to the V/K determined for i(6)A-ACSL substrates, an ∼6000-fold increase in enzymatic efficiency is imparted by ACSL(Trp)-MiaE interactions. The impact of substrate tRNA-MiaE interactions on protein secondary structure and active site electronic configuration was investigated using circular dichroism, dual-mode X-band electron paramagnetic resonance, and Mössbauer spectroscopies. These studies demonstrate that binding of tRNA to MiaE induces a protein conformational change that influences the electronic structure of the diiron site analogous to what has been observed for various bacterial multicomponent diiron monooxygenases upon titration with their corresponding effector proteins. These observations suggest that substrate-enzyme interactions may play a pivotal role in modulating the reactivity of the MiaE diiron active site. Moreover, the simplified monomeric (α) protein configuration exhibited by MiaE provide an unparalleled opportunity to study the impact of protein-effector interactions on non-heme diiron site geometry and reactivity.
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