Chaney M, Grande R, Wigneshweraraj S R, Cannon W, Casaz P, Gallegos M T, Schumacher J, Jones S, Elderkin S, Dago A E, Morett E, Buck M
Department of Biology and Biochemistry, Faculty of Life Sciences, Sir Alexander Fleming Building, Imperial College of Science Technology and Medicine, London SW7 2AZ, UK.
Genes Dev. 2001 Sep 1;15(17):2282-94. doi: 10.1101/gad.205501.
Conformational changes in sigma 54 (sigma(54)) and sigma(54)-holoenzyme depend on nucleotide hydrolysis by an activator. We now show that sigma(54) and its holoenzyme bind to the central ATP-hydrolyzing domains of the transcriptional activators PspF and NifA in the presence of ADP-aluminum fluoride, an analog of ATP in the transition state for hydrolysis. Direct binding of sigma(54) Region I to activator in the presence of ADP-aluminum fluoride was shown and inferred from in vivo suppression genetics. Energy transduction appears to occur through activator contacts to sigma(54) Region I. ADP-aluminum fluoride-dependent interactions and consideration of other AAA+ proteins provide insight into activator mechanochemical action.
σ54（σ(54)）及σ54全酶的构象变化取决于激活剂的核苷酸水解作用。我们现在表明，在ADP-氟化铝（一种处于水解过渡态的ATP类似物）存在的情况下，σ54及其全酶与转录激活剂PspF和NifA的中央ATP水解结构域结合。在ADP-氟化铝存在的情况下，σ54区域I与激活剂的直接结合已得到证实，并通过体内抑制遗传学推断得出。能量转导似乎是通过激活剂与σ54区域I的接触发生的。ADP-氟化铝依赖性相互作用以及对其他AAA+蛋白的考虑为激活剂的机械化学作用提供了见解。
