Before revision:  By analyzing the existing motility data of several types of molecular motors , we calculate the energetic cost (or efficiency) of generating time traces of a given precision. The energetic cost for kinesin-1 varies nonmonotonically with ATP concentration and load (f) , and is locally minimized at [ATP] \approx 200 \muM and f\approx 4 pN. Remarkably,  this local minimum vanishes and the cost increases significantly for a mutant that has a longer neck-linker , which underscores the importance of molecular structure in transport properties.
After revision:  By analyzing the existing motility data of several types of molecular motors show that \mathcal{Q ATP concentration and load (f) , and is locally minimized at [ATP] \approx 200 \muM and f\approx 4 pN. Remarkably, this local minimum vanishes and the cost increases significantly for a mutant that has a longer neck-linker , which underscores the importance of molecular structure in transport properties.