TABLE 2.

Function of Q252R-containing Env proteins

Env	Syncytiuma	Titerb	Bindingc	SU stabilityd
4070A	−	4.3 × 104 ± 0.6 × 104	+	+
G100R	−	4.1 × 105 ± 0.6 × 105	++	+
Q252R	+	<100	++	−
G100R/Q252R	++++	<100	+++	−
IIA/G100R/Q252R	++++	1.1 × 104 ± 0.3 × 104	+++	+
ΔH/G100R/Q252R	−	<100	+++	−

^aSyncytium formation in D17 gag-pol cells as in Table 1.

^bTiters were determined on D17 cells, as GFP (+) IU/ml.

^cBinding scored by comparing relative binding intensities between constructs. See Fig. 2 and 4 for detail.

^dSU stability is judged by Fig. 5B.