谷氨酰胺合成酶
操纵子
抑制因子
生物
生物化学
谷氨酰胺
腺苷酸化
细菌
心理压抑
抄写(语言学)
酶
谷氨酸合酶
转录因子
细胞生物学
遗传学
基因
生物合成
氨基酸
大肠杆菌
基因表达
语言学
哲学
作者
Brady A. Travis,Jared V Peck,Raul E. Salinas,Brandon J. Dopkins,Nicholas Lent,Viet Tue Nguyen,Mario J. Borgnia,Richard G. Brennan,Maria A. Schumacher
标识
DOI:10.1038/s41467-022-31573-0
摘要
Abstract How bacteria sense and respond to nitrogen levels are central questions in microbial physiology. In Gram-positive bacteria, nitrogen homeostasis is controlled by an operon encoding glutamine synthetase (GS), a dodecameric machine that assimilates ammonium into glutamine, and the GlnR repressor. GlnR detects nitrogen excess indirectly by binding glutamine-feedback-inhibited-GS (FBI-GS), which activates its transcription-repression function. The molecular mechanisms behind this regulatory circuitry, however, are unknown. Here we describe biochemical and structural analyses of GS and FBI-GS-GlnR complexes from pathogenic and non-pathogenic Gram-positive bacteria. The structures show FBI-GS binds the GlnR C-terminal domain within its active-site cavity, juxtaposing two GlnR monomers to form a DNA-binding-competent GlnR dimer. The FBI-GS-GlnR interaction stabilizes the inactive GS conformation. Strikingly, this interaction also favors a remarkable dodecamer to tetradecamer transition in some GS, breaking the paradigm that all bacterial GS are dodecamers. These data thus unveil unique structural mechanisms of transcription and enzymatic regulation.
科研通智能强力驱动
Strongly Powered by AbleSci AI