Malgieri Gaetano, Russo Luigi, Esposito Sabrina, Baglivo Ilaria, Zaccaro Laura, Pedone Emilia M, Di Blasio Benedetto, Isernia Carla, Pedone Paolo V, Fattorusso Roberto
Dipartimento di Scienze Ambientali, Seconda Università degli Studi di Napoli, Via Vivaldi 43, 81100 Caserta, Italy.
Proc Natl Acad Sci U S A. 2007 Oct 30;104(44):17341-6. doi: 10.1073/pnas.0706659104. Epub 2007 Oct 23.
The first putative prokaryotic Cys(2)His(2) zinc-finger domain has been identified in the transcriptional regulator Ros from Agrobacterium tumefaciens, indicating that the Cys(2)His(2) zinc-finger domain, originally thought to be confined to the eukaryotic kingdom, could be widespread throughout the living kingdom from eukaryotic, both animal and plant, to prokaryotic. In this article we report the NMR solution structure of Ros DNA-binding domain (Ros87), providing 79 structural characterization of a prokaryotic Cys(2)His(2) zinc-finger domain. The NMR structure of Ros87 shows that the putative prokaryotic Cys(2)His(2) zinc-finger sequence is indeed part of a significantly larger zinc-binding globular domain that possesses a novel protein fold very different from the classical fold reported for the eukaryotic classical zinc-finger. The Ros87 globular domain consists of 58 aa (residues 9-66), is arranged in a betabetabetaalphaalpha topology, and is stabilized by an extensive 15-residue hydrophobic core. A backbone dynamics study of Ros87, based on (15)N R(1), (15)N R(2), and heteronuclear (15)N-{(1)H}-NOE measurements, has further confirmed that the globular domain is uniformly rigid and flanked by two flexible tails. Mapping of the amino acids necessary for the DNA binding onto Ros87 structure reveals the protein surface involved in the DNA recognition mechanism of this new zinc-binding protein domain.
在根癌农杆菌的转录调节因子Ros中首次鉴定出假定的原核生物Cys(2)His(2)锌指结构域，这表明最初认为仅限于真核生物界的Cys(2)His(2)锌指结构域可能广泛存在于从动物和植物等真核生物到原核生物的整个生物界。在本文中，我们报道了Ros DNA结合结构域（Ros87）的核磁共振溶液结构，提供了对原核生物Cys(2)His(2)锌指结构域的结构特征描述。Ros87的核磁共振结构表明，假定的原核生物Cys(2)His(2)锌指序列确实是一个明显更大的锌结合球状结构域的一部分，该结构域具有一种与报道的真核生物经典锌指的经典折叠非常不同的新型蛋白质折叠。Ros87球状结构域由58个氨基酸（9 - 66位残基）组成，呈βββαα拓扑结构，并由一个广泛的15个残基的疏水核心稳定。基于(15)N R(1)、(15)N R(2)和异核(15)N - {(1)H}-NOE测量对Ros87进行的主链动力学研究进一步证实，球状结构域整体刚性，两侧有两条柔性尾巴。将DNA结合所需的氨基酸映射到Ros87结构上，揭示了参与这种新的锌结合蛋白结构域DNA识别机制的蛋白质表面。
