Table 1. Step Size, Run-Length, and Frequency of Backward Steps of Full-Length Myosin X, Myosin V, and Chimeras on Actin Filaments and Actin Bundles.

	Step size (nm) (2 μM ATP)			Run-length (μm) (2 mM ATP)
Construct	Mean	SD	n	Mean	SD	N	% backward steps
Full-length myosin X on actin filaments	–36.4	10.7	239	0.37	0.17	20	11%
	26.6	5.9
	38.1	6.3
	46.7	4.9
	61.4	4.4
	68.8	15.0
Full-length myosin X on actin bundles	–46.5	14.0	196	0.59	0.26	20	7%
	26.5	4.2
	49.5	10.0
	62.4	6.9
	78.2	8.4
	102.7	6.4
Myosin V on actin filaments	–35.3	13.7	176	0.83	0.40	20	5%
	36.3	11.1
	69.3	6.8
Myosin V on actin bundles	–26.2	12.1	169	0.64	0.26	20	3%
	36.9	10.3
	66.9	5.4
Chimera with the motor domain from myosin V and the lever arm and antiparallel coiled-coil domain from myosin X on actin filaments	–40.1	11.9	130	1.10	0.35	31	5%
	26.1	0.5
	42.9	9.8
	59.4	2.1
	71.7	4.8
	90.7	5.4
	115.8	4.3
Chimera with the motor domain from myosin V and the lever arm and antiparallel coiled-coil domain from myosin X on actin bundles	–46.9	9.2	138	1.12	0.43	28	9%
	33.7	1.2
	45.0	10.5
	56.8	1.7
	73.6	9.3
	94.3	2.2
	115.9	11.4
Chimera with the motor and lever arm domain from myosin X and the parallel coiled-coil domain from myosin V on actin filaments	–30.9	15.5	208	No processive motility			9%
	40.3	17.5
Chimera with the motor and lever arm domain from myosin X and the parallel coiled-coil domain from myosin V on actin bundles	–28.0	18.8	202	No processive motility			4%
	40.6	11.6
	72.7	5.9