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X-ray crystallographic and functional analysis of the class I DNA photolyase from Thermus thermophilus revealed the binding of flavin mononucleotide (FMN) as an antenna chromophore. The binding mode of FMN closely coincides with the binding of a deazaflavin-like chromophore in the related class I DNA photolyase from Anacystis nidulans. Compared to the R46E mutant, which lacks a conserved arginine in the binding site for the antenna chromophore, the FMN-comprising holophotolyase exhibits an eightfold higher activity at 450 nm. The facile incorporation of the flavin cofactors 8-hydroxy-deazariboflavin and 8-iodo-8-demethyl-riboflavin into the binding site for the antenna chromophore paves the way for wavelength-tuning of the activity spectra of DNA photolyases by using synthetic flavins.

Ultraviolet-B (UV-B, 280-320 nm) radiation may have severe negative effects on plants including damage to their genetic information. UV protection and DNA-repair mechanisms have evolved to either avoid or repair such damage. Since autotrophic plants are dependent on sunlight for their energy supply, an increase in the amount of UV-B reaching the earth's surface may affect the integrity of their genetic information if DNA damage is not repaired efficiently and rapidly. Here we show that overexpression of cyclobutane pyrimidine dimer (CPD) photolyase (EC 4.1.99.3) in Arabidopsis thaliana (L.), which catalyses the reversion of the major UV-B photoproduct in DNA (CPDs), strongly enhances the repair of CPDs and results in a moderate increase of biomass production under elevated UV-B.

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Background: Given the high prevalence of clinically relevant premenstrual symptoms and the associated impairment, there is a need for effective treatments. Initial evidence suggests cognitive-behavioural therapy (CBT) as an effective treatment for premenstrual dysphoric disorder (PMDD). The aim of the current randomized clinical trial was to evaluate an Internet-based CBT (iCBT) to reduce the burden of PMDD. Methods: In all, 174 women with PMDD were recruited via newspaper articles, flyers, and social media. They were randomized to a treatment group (TG; n = 86) or waitlist control group (CG; n = 88). Women of the TG received an 8-week therapist-guided iCBT. Data were assessed before and after treatment/waiting, and 6 months after intervention with prospective symptom diaries and questionnaires in the premenstrual phase. Treatment effects and moderators were analysed using hierarchical linear modelling. Results: Significant time × group interaction effects on functional impairment and psychological impairment, impact on everyday life, symptom intensity, and symptom disability in favour of the TG indicated the efficacy of the treatment. Follow-up assessments demonstrated treatment effects to be stable until 6 months after treatment. Additionally, significant interactions with moderator variables were found. In the TG, higher levels of active coping and lower levels of support-seeking coping were associated with stronger improvement in interference in everyday life and symptom intensity. In addition, lower levels of perceived stress were associated with stronger improvement in functional impairment. Conclusion: The iCBT was highly effective in reducing the burden of PMDD. It appears to be particularly important to address coping styles and stress management in the treatment.