Establishing the principles of recognition in the adenine-binding region of an aminoglycoside antibiotic kinase [APH(3′)-IIIa]
Establishing the principles of recognition in the adenine-binding region of an aminoglycoside antibiotic kinase [APH(3′)-IIIa]
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DOI：
10.1021/bi051085p
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发表时间：
2005-09-20
期刊：
影响因子：
2.9
通讯作者：
Cox, JR
中科院分区：
文献类型：
--
作者：
Boehr, DD;Farley, AR;Cox, JR
腺嘌呤环的基于蛋白质的分子识别在整个生物系统中都有意义。在这篇文章中，我们讨论了氨基糖苷类抗生素激酶[APH(3‘)-IIIa]的腺嘌呤结合区，它是结合腺嘌呤环蛋白质的一个很好的模型系统。这种酶利用水分子与酶主链/侧链原子的氢键网络和pi-pi堆积相互作用来识别腺嘌呤环。我们的方法利用定点突变、腺苷类似物和各种生物物理方法来探测APH(3‘)-IIIa的腺嘌呤结合区的接触。结果表明，在这个结合口袋中，腺嘌呤-Met90接触的性质是极性的，并且Met90，结构相似的Ser/Thr蛋白激酶中的“守门人”残基，在腺嘌呤结合中扮演着重要的角色。结果还表明，腺嘌呤环结构的微小变化可以导致这些类似物占据酶的腺嘌呤结合区的能力发生重大变化。另外的计算实验表明，在这个相互作用丰富的口袋中，尺寸和电子因素在芳香体系的结合中都是重要的。这项研究中建立的腺嘌呤识别原理可以应用于其他蛋白质-配体复合体，并用于指导未来旨在发现APH型酶的有效和选择性抑制剂的研究。
The protein-based molecular recognition of the adenine ring has implications throughout biological systems. In this paper, we discuss the adenine-binding region of an aminoglycoside antibiotic kinase [APH(3')-IIIa], which serves as an excellent model system for proteins that bind the adenine ring. This enzyme employs a hydrogen-bonding network involving water molecules along with enzyme backbone/side-chain atoms and a pi-pi stacking interaction to recognize the adenine ring. Our approach utilized site-directed mutagenesis, adenosine analogues and a variety of biophysical methods to probe the contacts in the adenine-binding region of APH(3')-IIIa. The results point to the polar nature of an adenine-Met90 contact in this binding pocket and the important role that Met90, the "gatekeeper" residue in structurally similar Ser/Thr protein kinases, plays in adenine binding. The results also suggest that small changes in the structure of the adenine ring can lead to significant changes in the ability of these analogues to occupy the adenine-binding region of the enzyme. Additional computational experiments indicate that both size and electronic factors are important in the binding of aromatic systems in this interaction-rich pocket. The principles governing adenine recognition established in this study may be applied to other protein-ligand complexes and used to navigate future studies directed at discovering potent and selective inhibitors of APH-type enzymes.