Crystal structure of the middle domain of human poly(A)-binding protein-interacting protein 1

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• 作者：Jian Lei^a ; Jeroen R. Mesters^a ; Albrecht von Brunn^b ; Rolf Hilgenfeld^a ; ^c ; ^d ; ^{hilgenfeld@biochem.uni-luebeck.de"" rel=""nofollow}
• 关键词：PABP ; Paip1 ; HEAT domain ; Eukaryotic translation initiation factors ; X-ray structure
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2011
• 出版时间：20 May 2011
• 年：2011
• 卷：408
• 期：4
• 页码：680-685
• 全文大小：1154 K

文摘

In eukaryotes, the poly(A)-binding protein (PABP) is one of the important factors for initiation of messenger RNA translation. PABP activity is regulated by the PABP-interacting proteins (Paips), which include Paip1, Paip2A, and Paip2B. Human Paip1 has three different isoforms. Here, we report the crystal structure of the middle domain of Paip1 isoform 2 (Paip1M) as determined by single-wavelength anomalous dispersion phasing. The structure reveals a crescent-shaped domain consisting of 10 α-helices and two antiparallel β-strands forming a β-hairpin. The 10 α-helices are arranged as five HEAT repeats which form a double layer of α helices with a convex and a concave surface. Despite low sequence identity, the overall fold of Paip1M is similar to the middle domain of human eIF4GII and yeast eIF4GI. Moreover, the amino-acid sequence motif and the local structure of eIF4G involved in binding of eIF4A, are conserved in Paip1. The structure reported here is the first of a member of the Paip family, thereby filling a gap in our understanding of initiation of eukaryotic mRNA translation in three dimensions.