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Nature:酵母U4/U6.U5 tri-snRNP的结构

摘要 : 在他们不到一年前发表的5.9Å低温电子显微镜结构基础上,Kiyoshi Nagai及同事现在又获得了酵母U4/U6.U5 tri-snRNP (在信使RNA的剪接中涉及的一个复合物)的3.7 Å分辨率的结构。

在他们不到一年前发表的5.9Å低温电子显微镜结构基础上,Kiyoshi Nagai及同事现在又获得了酵母U4/U6.U5 tri-snRNP (在信使RNA的剪接中涉及的一个复合物)的3.7 Å分辨率的结构。分辨率的提高有助于更好认识tri-snRNP的结构,也为剪接体的激发和催化核心的装配提供了新的功能信息。相关阅读:Science:清华大学施一公研究组揭示剪接体组装复合物U4/U6.U5 tri-snRNP三维结构


Cryo-EM structure of the yeast U4/U6.U5 tri-snRNP at 3.7 Å resolution


U4/U6.U5 tri-snRNP represents a substantial part of the spliceosome before activation. A cryo-electron microscopy structure of Saccharomyces cerevisiae U4/U6.U5 tri-snRNP at 3.7 Å resolution led to an essentially complete atomic model comprising 30 proteins plus U4/U6 and U5 small nuclear RNAs (snRNAs). The structure reveals striking interweaving interactions of the protein and RNA components, including extended polypeptides penetrating into subunit interfaces. The invariant ACAGAGA sequence of U6 snRNA, which base-pairs with the 5′-splice site during catalytic activation, forms a hairpin stabilized by Dib1 and Prp8 while the adjacent nucleotides interact with the exon binding loop 1 of U5 snRNA. Snu114 harbours GTP, but its putative catalytic histidine is held away from the γ-phosphate by hydrogen bonding to a tyrosine in the amino-terminal domain of Prp8. Mutation of this histidine to alanine has no detectable effect on yeast growth. The structure provides important new insights into the spliceosome activation process leading to the formation of the catalytic centre.

来源: Nature 浏览次数:0


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