Cerdan R, Cahuzac B, Félenbok B, Guittet E
Laboratoire de RMN, ICSN-CNRS, 1 av. de la Terrasse, Gif-sur-Yvette, F-91190, France.
J Mol Biol. 2000 Jan 28;295(4):729-36. doi: 10.1006/jmbi.1999.3417.
The three-dimensional structure of the DNA-binding domain (residues 1-60) of the ethanol regulon transcription factor AlcR from Aspergillus nidulans has been solved by NMR. This domain belongs to the zinc binuclear cluster class. Although the core of the protein is similar to previously characterized structures, consisting of two helices organized around a Zn(2)Cys(6 )motif, the present structure presents important variations, among them the presence of two supplementary helices. This structure gives new insight into the understanding of the AlcR specificities in DNA binding such as longer consensus half-sites, in vitro monomeric binding but in vivo multiple repeat transcriptional activation, either in direct or inverse orientations. The presence of additional contacts of the protein with its DNA target can be predicted from a model proposed for the interaction with the consensus DNA target. The clustering of accessible negative charges on helix 2 delineates a possible interaction site for other determinants of the transcriptional machinery, responsible for the fine tuning of the selection of the AlcR cognate sites.
构巢曲霉乙醇调节子转录因子AlcR的DNA结合结构域（第1至60位氨基酸残基）的三维结构已通过核磁共振解析。该结构域属于双核锌簇类。尽管该蛋白质的核心与先前表征的结构相似，由围绕Zn(2)Cys(6)基序组织的两个螺旋组成，但目前的结构存在重要差异，其中包括两个额外螺旋的存在。该结构为理解AlcR在DNA结合中的特异性提供了新的见解，例如更长的共有半位点、体外单体结合但体内多重复转录激活，无论是正向还是反向。从提出的与共有DNA靶标的相互作用模型可以预测该蛋白质与其DNA靶标存在额外的接触。螺旋2上可及负电荷的聚集描绘了转录机制其他决定因素的一个可能相互作用位点，负责微调AlcR同源位点的选择。
