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. Author manuscript; available in PMC: 2016 Mar 3.
Published in final edited form as: Biochemistry. 2015 Feb 19;54(8):1681–1693. doi: 10.1021/bi501171r

Table 2.

Effect of Alanine Mutation on JRFL Envelope Protein

Residue Cell-Cell Fusion Virus Entry
gp120a Expression gp41b Expression Fusione Category Effectf of Alanine Mutation gp120c Level gp41d Level Fusione Category Effectf of Alanine Mutation
L660A +++ ++++ WT - +++++ +++++ WT -
L661A +++++ +++++ WT - +++++ +++++ WT -
E662A +++++ +++++ WT - +++++ +++++ WT -
L663A +++ +++++ Abolished Severe defect +++++ +++++ WT -
D664A +++++ +++++ WT - ++++ +++++ Diminished -
K665A +++ +++++ WT - +++++ +++++ Diminished Mild defect
W666A +++++ +++++ Abolished Severe defect ++++ ++ Diminished -
S668A +++ +++++ WT - +++++ +++++ WT -
L669A +++++ +++++ WT - +++++ +++++ Enhanced Increased Env Expression
W670A +++++ +++++ WT - +++++ +++++ Diminished Mild defect
N671A + +++ Abolished - + +++++ Diminished Expression/Association
W672A ++++ +++++ WT - ++ ++++ WT Association
F673A +++ +++++ WT +++++ ++++ Diminished Mild defect
D674A +++++ +++++ Diminished Mild defect ++ ++ WT -
I675A ++++ +++++ WT - +++++ +++++ WT -
T676A ++++ +++++ WT - +++++ +++++ Diminished Mild defect
K677A +++++ +++++ WT - +++++ +++++ WT -
W678A ++ +++++ Enhanced Increased Env Expression +++++ ++++ WT -
L679A + +++ WT - +++++ +++++ Diminished Mild defect
W680A + +++ Enhanced Enhanced fusogenicity +++++ +++++ WT -
Y681A ++ +++ Enhanced Enhanced fusogenicity +++++ ++++ Diminished Mild defect
I682A + +++ WT - +++++ +++++ Enhanced Increased Env Expression
K683A ++++ +++++ Enhanced Increased Env Expression ++++ ++++ Diminished Mild defect
a, b

Protein (gp120 a, and gp41 b) levels were shown in the cell lysates used for cell–cell fusion and

c, d

Protein (gp120 c, and gp41 d) levels of expression shown in virus. The levels of protein expression were shown as follows: +, 0–20% of WT levels; ++, 20–50% of WT levels; +++, 50–80% of WT levels; ++++, >80% of WT levels; and +++++, >120% of WT levels.

e

Fusion categories were defined as follows: WT (no effect, WT level), diminished (20–80% of wild type), abolished (<20% of wild type), and enhanced ( >120% wild type).

f

Effect of alanine mutations were defined as follows, expression/folding (<20% of WT gp41), cleavage (<20% gp120 and gp41, WT level of gp160), association (<0.5of gp120/gp41 ratio), severe fusogenicity (>20 % of WT gp41, >0.5 gp120/gp41 ratio, < 20% of WT fusion level), mild fusogenicity (>20 % of WT gp41, >0.5 gp120/gp41 ratio, 20–80% of WT level), increased Env expression ( >120% of WT gp160 proteins and fusion level), and enhanced fusogenicity (>120% of WT fusion, WT gp160 expression level.)