TABLE 1.

Summary of characteristics of SOS gp140 variants

ResidueMutation in SOS gp140ExpressionaTrimer stabilitybCleavagec
L545F±±
N++±
P++±
G++±
I548V++±
L++±
H++±
N++±
S++±
G++±
R++±
L555VND
WND
YND
SND
PND
I559V+±
F±++
NND
P++++++
G+++++
R+++
L566V++++
I±±
N++
T++
P+±
K±±
T569S+±
P++++
K++
END
I573L++±
F++±
Y++±
Q++±
N++±
T++±
P++±
G++±
K++±
L576V±±
F±±
Y±±
Q±±
N±±
G±±
K±±
V580L++±
H++±
T++±
P++±
G++±
V583L++±
Q++±
N++±
S++±
P++±
R++±
K++±
L587A±±
P±±
R±±
D±±
E±±
  • a Relative scale: −, no expression; ±, minimal expression; +, expression level lower than that of wild-type SOS gp140; ++, expression level equivalent to that of wild-type SOS gp140; +++, expression level greater than that of wild-type SOS gp140. All proteins were expressed in the presence of cotransfected furin, which decreases gp140 expression (5, 6, 79). The data were derived from at least three independent transfections.

  • b As assessed by BN-PAGE. The trimer stability of SOS gp140 was set at ± (some trimers were present in some transfections). The maximum amount of trimers (++) was found only in gp140 variants containing substitutions at residue Ile-559 and ranged from 40 to >90% of total Env expression in independent transfections. The data were derived from at least three independent transfections. ND, not determined (no expression).

  • c Data were derived from Fig. 2C. Symbols are as defined in footnote a.