Solution Structure of the First HMG Box Domain in Human Upstream Binding Factor

详细信息    查看全文

• 作者：Yingqi Xu ; Wulin Yang ; Jihui Wu ; and Yunyu Shi
• 刊名：Biochemistry
• 出版年：2002
• 出版时间：April 30, 2002
• 年：2002
• 卷：41
• 期：17
• 页码：5415 - 5420
• 全文大小：266K
• 年卷期：v.41,no.17(April 30, 2002)
• ISSN：1520-4995

文摘

Human upstream binding factor is a nucleolar transcription factor involved in transcription byRNA polymerase I. It contains six HMG box domains; the HMG box is a minor groove DNA-bindingdomain that has been found in hundreds of proteins with different functions. Among the six HMG boxdomains in hUBF, the first one can bind to the ribosomal promoter specifically by itself and is essentialfor the whole protein's DNA binding specificity. Here we report the three-dimensional structure of thisfirst HMG box free in solution determined by multidimensional NMR using ¹³C,¹⁵N-labeled protein. Likethe previously determined HMG box structures, hUBF HMG box 1 adopts a twisted L-shape consistingof three -helices: helix 1 (17-30) and helix 2 (38-51) pack onto each other to form the short arm,while helix 3 (57-76) is associated with an extended strand N-terminal to helix 1 and forms the longarm. A cluster of conserved residues, in particular the aromatic residues F21, Y49, and Y60, is importantto maintain the fold. The short arm is rigid due to extensive hydrophobic interaction between helix 1 andhelix 2, while the long arm is less rigid.