Cytoskeletal active nematics exhibit striking nonequilibrium dynamics that are powered by energy-consuming molecular motors. To gain insight into the structure and mechanics of these materials, we design programmable clusters in which kinesin motors are linked by a double-stranded DNA linker. The efficiency by which DNA-based clusters power active nematics depends on both the stepping dynamics of the kinesin motors and the chemical structure of the polymeric linker. Fluorescence anisotropy measurements reveal that the motor clusters, like filamentous microtubules, exhibit local nematic order. The properties of the DNA linker enable the design of force-sensing clusters. When the load across the linker exceeds a critical threshold, the clusters fall apart, ceasing to generate active stresses and slowing the system dynamics. Fluorescence readout reveals the fraction of bound clusters that generate interfilament sliding. In turn, this yields the average load experienced by the kinesin motors as they step along the microtubules. DNA-motor clusters provide a foundation for understanding the molecular mechanism by which nanoscale molecular motors collectively generate mesoscopic active stresses, which in turn power macroscale nonequilibrium dynamics of active nematics.

细胞骨架活性向列体表现出惊人的非平衡动力学，由耗能分子马达驱动。为了深入了解这些材料的结构和力学，我们设计了可编程簇，其中驱动蛋白电机通过双链 DNA 接头连接。基于 DNA 的簇为活性向列提供动力的效率取决于驱动蛋白电机的步进动力学和聚合物接头的化学结构。荧光各向异性测量表明，运动簇，如丝状微管，表现出局部向列顺序。DNA 接头的特性使力感应簇的设计成为可能。当链接器上的负载超过临界阈值时，集群会分崩离析，不再产生主动应力并减慢系统动态。荧光读数揭示了产生丝间滑动的结合簇的比例。反过来，这会产生驱动蛋白电机在沿着微管前进时所经历的平均负载。DNA-马达簇为理解纳米级分子马达共同产生介观主动应力的分子机制提供了基础，这反过来又为主动向列相的宏观非平衡动力学提供动力。