STRUCTURE AND FUNCTION OF THE B/HLH/Z DOMAIN OF USF
STRUCTURE AND FUNCTION OF THE B/HLH/Z DOMAIN OF USF
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DOI：
10.1002/j.1460-2075.1994.tb06247.x
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发表时间：
1994-01-01
期刊：
影响因子：
11.4
通讯作者：
BURLEY, SK
中科院分区：
文献类型：
--
作者：
FERREDAMARE, AR;POGNONEC, P;BURLEY, SK
碱性/螺旋-环-螺旋/亮氨酸拉链（B/HLH/Z）转录因子上游刺激因子（USF）及其分离的DNA结合结构域在识别其同源DNA时经历无规卷曲至α-螺旋折叠转变。USF B/HLH共晶体结构类似于同源蛋白Max的B/HLH/Z结构域的结构，并揭示了（i）截短的B/HLH DNA结合结构域同源二聚化，形成平行的左旋四螺旋束，和（ii）碱性区域在结合到DNA序列CACGTG的大沟时变成α螺旋。流体力学测量表明USF的B/HLH/Z DNA结合结构域以二价同源四聚体形式存在。这种四聚体在USF生理核内浓度下形成，并且取决于亮氨酸拉链蛾的完整性。同时结合到两个独立位点的能力表明了真核转录因子的B/HLH/Z和Myc相关家族在DNA成环中的作用。
The basic/helix-loop-helix/leucine zipper (b/HLH/Z) transcription factor upstream stimulatory factor (USF) and its isolated DNA binding domain undergo a random coil to alpha-helix folding transition on recognizing their cognate DNA. The USF b/HLH cocrystal structure resembles the structure of the b/HLH/Z domain of the homologous protein Max and reveals (i) that the truncated, b/HLH DNA binding domain homodimerizes, forming a parallel, left-handed four-helix bundle, and (ii) that the basic region becomes alpha-helical on binding to the major groove of the DNA sequence CACGTG. Hydrodynamic measurements show that the b/HLH/Z DNA binding domain of USF exists as a bivalent homotetramer. This tetramer forms at the USF physiological intranuclear concentration, and depends on the integrity of the leucine zipper moth. The ability to bind simultaneously to two independent sites suggests a role in DNA looping for the b/HLH/Z and Myc-related families of eukaryotic transcription factors.