TABLE 1.

Properties of WT and mutant gH2 forms

Deletion or mutation	Surface expression		gL2 binding	CHL2 binding	Cell-cell fusion (%)	Complementation (%)
	Without gL	With gL
None (WT)	−	+	+	+	100	100.0
Δ29	−	+	+	+	107	55.5
Δ48	+	+	+	+	94	58.1
Δ64	+	+	+	+a	3	0.2
Δ72	+	+	+	+a	10	0.1
Δ48-71	+	+	+	+a	7	1.5
Δ48-63	+	+	+	+a	4	2.3
Δ62-72	−	+	+	+a	5	0
G64A	NDb	+	+	+	71	54.5
R65A	ND	+	+	+	60	51.6
L66A	−	+	+	+a	29	9.6
P68A	ND	+	+	+	77	65.4
P69A	ND	+	+	+	43	30.0
G70A	ND	+	+	+	93	67.1
E71A	−	+	+	+	89	81.0
L72A	−	Reduced	−c	−	6	0.8
T75A	ND	+	+	+	60	33.8

^aBound only if CHL2 was added prior to the fixation step (see Materials and Methods).

^bND, not determined.

^cgL binding was undetectable by CELISA and immunofluorescence assay; however, gL coexpression was required for cell surface expression of gH2-L72A.