The pathogenic U3271C human mitochondrial tRNA(Leu(UUR)) mutation disrupts a fragile anticodon stem.
The pathogenic U3271C human mitochondrial tRNA(Leu(UUR)) mutation disrupts a fragile anticodon stem.
复制标题
致病性 U3271C 人类线粒体 tRNA (Leu(UUR)) 突变会破坏脆弱的反密码子茎。
DOI：
10.1093/nar/gkg131
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发表时间：
2003
影响因子：
14.9
通讯作者：
Kelley,ShanaO
中科院分区：
文献类型：
--
作者：
Wittenhagen,LisaM;Roy,MarcD;Kelley,ShanaO
The U3271C mutation affecting the human mitochondrial transfer RNALeu(UUR)(hs mt tRNA) is correlated with diabetes and mitochondrial encephalopathies. We have explored the relationship between the structural effects of this mutation and its impact on function using chemical probing experiments andin vitroaminoacylation assays to investigate a series of tRNA constructs. Chemical probing experiments indicate that the U3271C substitution, which replaces an AU pair with a CA mispair, significantly destabilizes the anticodon stem. The introduction of a compensatory A3261G mutation reintroduces base pairing at this site and restores the structure of this domain. In fact, the anticodon stem of the A3261G/U3271C mutant appears more structured than wild‐type (WT) hs mt tRNALeu(UUR), indicating that the entirely AU stem of the native tRNA is intrinsically weak. The results of the chemical probing experiments are mirrored in the aminoacylation activities of the mutants. The U3271C substitution decreases aminoacylation reactivity relative to the WT tRNA due to an increase inKmfor the pathogenic mutant. The binding defect is a direct result of the structural disruption caused by the pathogenic mutation, as the introduction of the stabilizing compensatory mutation restores aminoacylation activity. Other examples of functional defects associated with the disruption of weak domains in hs mt tRNAs have been reported, indicating that the effects of pathogenic mutations may be amplified by the fragile structures that are characteristic of this class of tRNAs.
