Molecular mechanism of clock regulation and signal transduction by a heme sensor transcription factor, NPAS2

我们分析了气态小分子对NPAS2功能的影响，NPAS2是一种与哺乳动物昼夜节律相关的血红素蛋白。NPAS2的转录活性和DNA结合活性受CO或NO的影响呈浓度依赖性，提示昼夜节律与CO-、NO信号系统之间存在串扰。突变体分析显示，PASA血红素结构域的特定氨基酸残基对分子的信号转导至关重要。

We analyzed the effects of gaseous small molecules on function of NPAS2, a heme protein associated with mammalian circadian rhythms. The transcriptional activity and DNA binding activity of NPAS2 were affected in a concentration-dependent-manner by CO or NO, suggesting cross talk between circadian rhythm and CO-, NO-signaling system. The analysis of mutants revealed that specific amino-acid residues in the PASA heme domain are essential to signal transduction in the molecule.