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Aflatoxin biosynthesis regulators AflR and AflS: DNA binding affinity, stoichiometry, and kineticsстатья Исследовательская статья
Дата последнего поиска статьи во внешних источниках: 19 июня 2024 г.
- Авторы: Abbas Asmaa, Prajapati Ranjit K., Aalto-Setälä Emil, Baykov Alexander A., Malinen Anssi M.
- Журнал: Biochemical Journal
- Том: 481
- Номер: 12
- Год издания: 2024
- Издательство: Portland Press, Ltd.
- Местоположение издательства: United Kingdom
- Первая страница: 805
- Последняя страница: 821
- DOI: 10.1042/bcj20240084
- Аннотация: Aflatoxins (AFs), potent foodborne carcinogens produced byAspergillusfungi, pose significant health risks worldwide and present challenges to food safety and productivity in the food chain. Novel strategies for disrupting AF production, cultivating resilient crops, and detecting contaminated food are urgently needed. Understanding the regulatorymechanisms of AF production is pivotal for targeted interventions to mitigate toxin accumulation in food and feed. The gene cluster responsible for AF biosynthesis encodes biosynthetic enzymes and pathway-specific regulators, notably AflR and AflS. While AflR, a DNA-binding protein, activates gene transcription within the cluster, AflS enhances AFproduction through mechanisms that are not fully understood. In this study, we developed protocols to purify recombinant AflR and AflS proteins and utilized multiple assays to characterize their interactions with DNA. Our biophysical analysis indicated that AflR and AflS form a complex. AflS exhibited no DNA-binding capability on its own but unexpectedly reduced the DNA-binding affinity of AflR. Additionally, we found that AflR achieves its binding specificity through a mechanism in which either two copies of AflR or its complex with AflS bind to target sites on DNA in a highly cooperative manner. The estimated values of the interaction parameters of AflR, AflS and DNA target sites constitute a fundamental framework against which the function and mechanisms of other AF biosynthesis regulators can be compared.
- Добавил в систему: Байков Александр Андреевич