TABLE 1.

Comparison of calculated and experimental masses of endogenous wild-type and expressed actins

As described under “Results,” WT actin (endogenous Dictyostelium actin) has an N-terminal acetyl group, whereas the expressed actins have an N-terminal glycyl group in addition (except for Y/Y) to the indicated mutation of Tyr-53.

Actin	Calculated mass	Experimental mass
	Da	Da
WT	41,657.7	41,657.9
Y/Y	41,672.7	41,672.8
Y/F	41,656.7	41,656.6
Y/A	41,580.6	41,580.6
Y/E	41,638.6	41,638.4
Y/W	41,695.7	41,695.4
Y/L	41,622.7	41,622.7