Table 3.

In vitro activity of wild type and mutant forms of Myo2p

Myo2p samplea	Activity (± SD)
In vitro motility (μm · s−1)b
Wild type	0.42 ± 0.06
Rlc1p-S35A-S36A	0.12 ± 0.04
Rlc1p-S35D-S36D	0.41 ± 0.07
Rlc1p-NΔ	0.46 ± 0.04
Myo2p-S1444A	0.40 ± 0.06
Myo2p-S1444D	0.44 ± 0.08
Myo2p-S1444A/Rlc1p-S35A-S36A	0.14 ± 0.02
Myo2p-S1444A/Rlc1p-S35D-S36D	0.46 ± 0.11
Myo2p-S1444D/Rlc1p-S35A-S36A	0.16 ± 0.03
Myo2p-S1444D/Rlc1p-S35D-S36D	0.59 ± 0.05

	Actin-activated Mg2+-ATPasec
	KM (μM)	Vmax (s−1)d
Wild type	19.9 ± 3.2	3.2 ± 0.2
Rlc1p-S35A-S36A	16.9 ± 4.2	2.7 ± 0.2
Rlc1p-S35D-S36D	18.6 ± 4.3	3.0 ± 0.2

^a Each Myo2p sample is made up of the Myo2p heavy chain, ELC Cdc4p, and Rlc1p. Relevant mutations are indicated.

^b n = 60 filaments. Motility was performed using one-step purified Myo2p samples.

^c ATPase values for Rlc1p-AA and -DD samples are derived from the curves in Figure 6A.

^d ATPase activity: moles of ATP hydrolyzed per motor per second.