A Novel Type of Zinc Finger DNA Binding Domain in the Agrobacterium tumefaciens Transcriptional Regulator Ros

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• 作者：Sabrina Esposito ; Ilaria Baglivo ; Gaetano Malgieri ; Luigi Russo ; Laura Zaccaro ; Luca D. D'Andrea ; Marco Mammucari ; Benedetto Di Blasio ; Carla Isernia ; Roberto Fattorusso ; Paolo V. Pedone
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：August 29, 2006
• 年：2006
• 卷：45
• 期：34
• 页码：10394 - 10405
• 全文大小：438K
• 年卷期：v.45,no.34(August 29, 2006)
• ISSN：1520-4995

文摘

Transcriptional factors bearing a Cys₂His₂ zinc finger were thought to be confined to eukaryotes,but recent studies have suggested their presence also in prokaryotes. In this paper, we report the firstcomplete functional characterization of the DNA binding domain present in the putative Cys₂His₂ zincfinger-containing prokaryotic transcriptional regulator Ros from Agrobacterium tumefaciens. Wedemonstrate that in the single zinc binding motif present in the Ros protein the metal ion is coordinatedby two cysteines (Cys79 and Cys82) and two histidines (His92 and His97), separated by a shorter spacerwith respect to the eukaryotic classical Cys₂His₂ domains. The Cys₂His₂ zinc finger motif is essential forRos DNA binding and is part of a larger DNA binding domain which includes four basic regions locatedon either side of the finger, one at the N-terminus and three at the C-terminus. The one described here isa novel type of DNA binding domain containing a noncanonical Cys₂His₂ zinc finger motif which, bysequence alignment, seems to be conserved in all the bacterial putative zinc finger proteins identified sofar. Interestingly, basic amino acids have been shown to be important in stabilizing the DNA binding ofeukaryotic single Cys₂His₂ zinc finger domains, confirming that the modality of DNA binding using asingle zinc finger motif flanked by basic residues is widespread throughout the living kingdom fromeukaryotic, both animal and plant, to prokaryotic, even if in each kingdom it presents its peculiarity.