TABLE 1.

Phenotypes of RBD mutants

Name	Mutation	Relative binding (%)a	Receptor-triggered protease sensitivityb	Receptor-triggered membrane associationb	Relative infectivity (%)a
wtc		100	+	+	100
M20	R213A/K227A	14	+	Delayede	7
M21	R213A/R223A/R234A	11	−d	−	5
M28	R213S	91	+	−	5

^aFrom reference 42. 

^b+, present; −, absent. 

^cwt, wild type. 

^dSensitivity to thermolysin was independent of sTva. 

^eMembrane association was delayed.