MLN51 可刺激 eIF4AIII 的 RNA 解旋酶活性。
MLN51 stimulates the RNA-helicase activity of eIF4AIII.
机构信息
Laboratory of Macromolecular Structure, Institute of Molecular and Cell Biology, Singapore, Singapore.
出版信息
PLoS One. 2007 Mar 21;2(3):e303. doi: 10.1371/journal.pone.0000303.
The core of the exon-junction complex consists of Y14, Magoh, MLN51 and eIF4AIII, a DEAD-box RNA helicase. MLN51 stimulates the ATPase activity of eIF4AIII, whilst the Y14-Magoh complex inhibits it. We show that the MLN51-dependent stimulation increases both the affinity of eIF4AIII for ATP and the rate of enzyme turnover; the K(M) is decreased by an order of magnitude and k(cat) increases 30 fold. Y14-Magoh do inhibit the MLN51-stimulated ATPase activity, but not back to background levels. The ATP-bound form of the eIF4AIII-MLN51 complex has a 100-fold higher affinity for RNA than the unbound form and ATP hydrolysis reduces this affinity. MLN51 stimulates the RNA-helicase activity of eIF4AIII, suggesting that this activity may be functionally important.
外显子-接头复合物的核心由 Y14、Magoh、MLN51 和 eIF4AIII（一种 DEAD-box RNA 解旋酶）组成。MLN51 刺激 eIF4AIII 的 ATP 酶活性，而 Y14-Magoh 复合物则抑制其活性。我们表明，MLN51 依赖性刺激可同时提高 eIF4AIII 对 ATP 的亲和力和酶转化的速率；K（M）降低了一个数量级，k（cat）增加了 30 倍。Y14-Magoh 确实会抑制 MLN51 刺激的 ATP 酶活性，但不会降低到背景水平。与未结合形式相比，ATP 结合形式的 eIF4AIII-MLN51 复合物对 RNA 的亲和力高 100 倍，并且 ATP 水解会降低这种亲和力。MLN51 刺激 eIF4AIII 的 RNA 解旋酶活性，表明这种活性可能具有功能重要性。
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