KIF20A是细胞分裂的关键动力蛋白和有望的抗癌药物靶点。其细胞角色的机制仍然不明。有趣的是，这种马达蛋白-6的核苷酸结合位点和微管结合位点之间存在异常的耦合，但其导致非典型运动性质的发散序列的机制知之甚少。我们在此呈现了其马达结构的第一个高分辨率结构，描述了马达蛋白高度不寻常的结构特征，包括插入到核心马达结构中并极大影响变构和ATP水解活性的长L6插入。结合高分辨率的冷冻电镜微管结合KIF20A结构，我们剖析了影响其力学化学特性的KIF20A序列的特殊之处，从而导致与其他马达蛋白相比较低的运动性。从KIF20A的前动力周期构象中可以得到结构和功能洞察，强调了延长插入在塑造马达的力学化学周期中的作用。在马达蛋白中，颈链连接物的长度对力量产生和过程性是必不可少的。我们在这里强调颈链连接物前序列在控制其向后对接方面的作用，并展示了一个比kinesin-1颈链连接物长四倍的颈链连接物是这个马达蛋白的活性所需。

KIF20A is a critical kinesin for cell division and a promising anti-cancer drug target. The mechanisms underlying its cellular roles remain elusive. Interestingly, unusual coupling between the nucleotide- and microtubule-binding sites of this kinesin-6 has been reported, but little is known about how its divergent sequence leads to atypical motility properties. We present here the first high-resolution structure of its motor domain that delineates the highly unusual structural features of this motor, including a long L6 insertion that integrates into the core of the motor domain and that drastically affects allostery and ATPase activity. Together with the high-resolution cryo-electron microscopy microtubule-bound KIF20A structure that reveals the microtubule-binding interface, we dissect the peculiarities of the KIF20A sequence that influence its mechanochemistry, leading to low motility compared to other kinesins. Structural and functional insights from the KIF20A pre-power stroke conformation highlight the role of extended insertions in shaping the motor's mechanochemical cycle. Essential for force production and processivity is the length of the neck linker in kinesins. We highlight here the role of the sequence preceding the neck linker in controlling its backward docking and show that a neck linker four times longer than that in kinesin-1 is required for the activity of this motor.