Structure of a genetically engineered molecular motor
Structure of a genetically engineered molecular motor
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DOI：
10.1093/emboj/20.1.40
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发表时间：
2001-01-15
期刊：
影响因子：
11.4
通讯作者：
Kull, FJ
中科院分区：
文献类型：
--
作者：
Kliche, W;Fujita-Becker, S;Kull, FJ
分子马达沿着聚合物轨道单向移动，以依赖于ATP的方式产生运动和力。他们通过将核苷酸结合区的小构象变化放大为更大蛋白质结构域的强力运动来实现这一点。我们介绍了一种基于肌动蛋白的人造马达的2.8埃分辨率的晶体结构。通过将肌球蛋白II的催化结构域与由α-肌动蛋白重复序列1和2组成的130 Angstrom构象放大器相结合，我们证明了通过基因工程设计具有精确定义的杠杆臂长度和特定运动特性的单多肽分子马达是可能的。此外，我们的结构显示了在核苷酸结合区突变保守盐桥的后果。这一盐桥的破坏似乎干扰了肌球蛋白催化活性的闭合构象的形成。盐桥已知会严重抑制ATP的水解活性。最后，我们描述了α-肌动蛋白重复序列1和2的结构是由两个由不间断的α-螺旋连接的刚性三螺旋束组成的。该折叠非常类似于前面描述的α-肌动蛋白重复序列2和3，以及α-光谱蛋白重复序列16和17的结构。
Molecular motors move unidirectionally along polymer tracks, producing movement and force in an ATP-dependent fashion. They achieve this by amplifying small conformational changes in the nucleotide-binding region into force-generating movements of larger protein domains. We present the 2.8 Angstrom resolution crystal structure of an artificial actin-based motor. By combining the catalytic domain of myosin II with a 130 Angstrom conformational amplifier consisting of repeats 1 and 2 of alpha -actinin, we demonstrate that it is possible to genetically engineer single-polypeptide molecular motors with precisely defined lever arm lengths and specific motile properties. Furthermore, our structure shows the consequences of mutating a conserved salt bridge in the nucleotide-binding region. Disruption of this salt bridge, which is known to severely inhibit ATP hydrolysis activity, appears to interfere with formation of myosin's catalytically active 'closed' conformation. Finally, we describe the structure of alpha -actinin repeats 1 and 2 as being composed of two rigid, triple-helical bundles linked by an uninterrupted alpha -helix. This fold is very similar to the previously described structures of alpha -actinin repeats 2 and 3, and alpha -spectrin repeats 16 and 17.