位于核酶结构域核心的镁离子。

A magnesium ion core at the heart of a ribozyme domain.

作者信息

Cate J H, Hanna R L, Doudna J A

机构信息

Dept. of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.

出版信息

Nat Struct Biol. 1997 Jul;4(7):553-8. doi: 10.1038/nsb0797-553.

DOI:10.1038/nsb0797-553

PMID:9228948

Abstract

Large ribozymes require divalent metal ions to fold. We show here that the tertiary structure of the Tetrahymena group I intron P4-P6 domain nucleates around a magnesium ion core. In the domain crystal structure, five magnesium ions bind in a three-helix junction at the centre of the molecule. Single atom changes in any one of four magnesium sites in this three-helix junction destroy folding of the entire 160-nucleotide P4-P6 domain. The magnesium ion core may be the RNA counterpart to the protein hydrophobic core, burying parts of the RNA molecule in the native structure.

摘要

大型核酶需要二价金属离子来折叠。我们在此表明，嗜热四膜虫I组内含子P4 - P6结构域的三级结构围绕镁离子核心成核。在该结构域的晶体结构中，五个镁离子结合在分子中心的一个三螺旋连接处。这个三螺旋连接处四个镁位点中任何一个的单个原子变化都会破坏整个160个核苷酸的P4 - P6结构域的折叠。镁离子核心可能是蛋白质疏水核心的RNA对应物，在天然结构中掩埋RNA分子的部分区域。