Structure of superoxide reductase bound to ferrocyanide and active site expansion upon X-ray-induced photo-reduction.

International audienceSome sulfate-reducing and microaerophilic bacteria rely on the enzyme superoxide reductase (SOR) to eliminate the toxic superoxide anion radical (O2*-). SOR catalyses the one-electron reduction of O2*- to hydrogen peroxide at a nonheme ferrous iron center. The structures of Desulfoarculus baarsii SOR (mutant E47A) alone and in complex with ferrocyanide were solved to 1.15 and 1.7 A resolution, respectively. The latter structure, the first ever reported of a complex between ferrocyanide and a protein, reveals that this organo-metallic compound entirely plugs the SOR active site, coordinating the active iron through a bent cyano bridge. The subtle structural differences between the mixed-valence and the fully reduced SOR-ferrocyanide adducts were investigated by taking advantage of the photoelectrons induced by X-rays. The results reveal that photo-reduction from Fe(III) to Fe(II) of the iron center, a very rapid process under a powerful synchrotron beam, induces an expansion of the SOR active site

Raman-assisted crystallography reveals end-on peroxide intermediates in a nonheme iron enzyme.

International audienceIron-peroxide intermediates are central in the reaction cycle of many iron-containing biomolecules. We trapped iron(III)-(hydro)peroxo species in crystals of superoxide reductase (SOR), a nonheme mononuclear iron enzyme that scavenges superoxide radicals. X-ray diffraction data at 1.95 angstrom resolution and Raman spectra recorded in crystallo revealed iron-(hydro)peroxo intermediates with the (hydro)peroxo group bound end-on. The dynamic SOR active site promotes the formation of transient hydrogen bond networks, which presumably assist the cleavage of the iron-oxygen bond in order to release the reaction product, hydrogen peroxide

One small step for man, one giant leap for men's health: A meta-analysis of behaviour change interventions to increase men's physical activity

Objective To determine the effects of behaviour change interventions on men’s physical activity (postintervention), sustained change in physical activity behaviour (≥12 months postintervention) and to identify variations in effects due to potential moderating variables (eg, theoretical underpinning, gender-tailored, contact frequency). Design Systematic review with meta-analysis. Pooled effect size (Cohen’s d) was calculated assuming a random-effects model. Homogeneity and subsequent exploratory moderator analyses were assessed using Q, T2 and I2. Data sources Medline, EMBASE, CINAHL, SportDiscus and Web of Science to April 2019. Eligibility criteria for selected studies Randomised control trials of behaviour change interventions in men (≥18 years) where physical activity was an outcome and data were from men-only studies or disaggregated by sex. Results Twenty-six articles described 24 eligible studies. The overall mean intervention effect on men’s physical activity was 0.35 (SE=0.05; 95% CI 0.26 to 0.45;

Investigating the sleep habits in individual and team-sport athletes using the athlete sleep behaviour questionnaire and the Pittsburgh sleep quality index.

Objectives: There is limited large-scale data on maladaptive sleep practices in elite adult athletes and their influence on sleep characteristics. This study aimed to identify differences in sleep behaviours between individual and team-sport athletes using two sleep questionnaires. Methods: 407 (237 male, 170 female) elite adult athletes across sixteen sports (9 individual-sports, 7 teamsports) completed the Athlete Sleep Behavior Questionnaire (ASBQ) and the Pittsburgh Sleep Quality Index (PSQI). Results: Individual-sport athletes reported greater total sleep time and higher sleep efficiency than team-sport athletes (p < 0.05, d = 0.28-0.29). There were no differences between global scores for the PSQI, however, there was a difference between global scores for the ASBQ as well as multiple individual items from both questionnaires (p < 0.05), indicating poorer behaviours in team-sport athletes. Discussion: Team-sport athletes displayed more maladaptive pre-sleep behaviours and poorer sleep characteristics than individual-sport athletes

Infographic. Wake up and smell the coffee

[No abstract available