A common speed limit for RNA-cleaving ribozymes and deoxyribozymes
A common speed limit for RNA-cleaving ribozymes and deoxyribozymes
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DOI：
10.1261/rna.5670703
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发表时间：
2003-08-01
期刊：
影响因子：
4.5
通讯作者：
Sudarsan, N
中科院分区：
文献类型：
--
作者：
Breaker, RR;Emilsson, GM;Sudarsan, N
人们普遍认为，蛋白质主导生物催化的原因是，与核酸相比，多肽具有更大的化学复杂性，因此应该具有更大的酶促能力。与这一假设一致的是，蛋白酶通常表现出比天然和工程核酶所实现的化学速率增强要大得多的事实。为了研究核酸的真正催化能力，我们确定了 14 类工程核酶和脱氧核酶的动力学特征，这些核酶和脱氧核酶通过内部磷酸酯转移加速 RNA 裂解。一半接近最大速率常数，大约为 1 分钟(-1)，而核糖核酸酶 A 催化相同反应的速度大约快 80,000 倍。额外的生化分析表明，这种常见的核酶“速度限制”与仅使用两种特定催化策略的酶的理论最大速率增强一致。这些结果表明，可以使用额外的催化策略来制造核酶，以与蛋白质相同的速率增强来促进 RNA 裂解。
It is widely believed that the reason proteins dominate biological catalysis is because polypeptides have greater chemical complexity compared with nucleic acids, and thus should have greater enzymatic power. Consistent with this hypothesis is the fact that protein enzymes typically exhibit chemical rate enhancements that are far more substantial than those achieved by natural and engineered ribozymes. To investigate the true catalytic power of nucleic acids, we determined the kinetic characteristics of 14 classes of engineered ribozymes and deoxyribozymes that accelerate RNA cleavage by internal phosphoester transfer. Half approach a maximum rate constant of similar to1 min(-1), whereas ribonuclease A catalyzes the same reaction similar to80,000-fold faster. Additional biochemical analyses indicate that this commonly encountered ribozyme "speed limit" coincides with the theoretical maximum rate enhancement for an enzyme that uses only two specific catalytic strategies. These results indicate that ribozymes using additional catalytic strategies could be made that promote RNA cleavage with rate enhancements that equal those of proteins.