Induced Fit and “Lock and Key” Recognition of 5 S RNA by Zinc Fingers of Transcription Factor IIIA

详细信息    查看全文

• 作者：Brian M. Lee ; Jing Xu ; Bryan K. Clarkson ; Maria A. Martinez-Yamout ; H. Jane Dyson ; David A. Case ; Joel M. Gottesfeld and Peter E. Wright
• 刊名：Journal of Molecular Biology
• 出版年：2006
• 出版时间：17 March 2006
• 年：2006
• 卷：357
• 期：1
• 页码：275-291
• 全文大小：1292 K

文摘

Transcription factor IIIA (TFIIIA) is a Cys<sub>2sub>His<sub>2sub> zinc finger protein that regulates expression of the 5 S ribosomal RNA gene by binding specifically to the internal control element. TFIIIA also functions in transport and storage of 5 S RNA by binding directly to the RNA transcript. To obtain insights into the mechanism by which TFIIIA recognizes 5 S RNA, we determined the solution structure of the middle three zinc fingers bound to the central core of 5 S RNA. Finger 4 utilizes “lock and key” recognition to bind in the widened major groove of the pre-structured RNA loop E motif. This interaction is mediated by direct hydrogen bonding interactions with bases. In contrast, recognition of loop A, a flexible junction of three helices, occurs by an induced fit mechanism that involves reorganization of the conserved CAUA motif and structuring of the finger 5–finger 6 interface to form a complementary RNA binding surface.