Table I

Cysteine-mutant Channels that Reacted with MTS Derivatives

MutantpH Conditions (cis/trans)Reagents cisReagents transPercent change in conductanceΔ FlickeringNo. reactions observed
V329C5.2/7.2EAEA0*
7.2/7.2EA+50+++++ 2
7.2/7.2EA+50+++++3–4
7.2/7.2EAEA+50+++++ 1
A330C5.2/7.2EA−10NC2–3
7.2/7.2EA−27NC 7
Q331C5.2/7.2EA−73NC 1
7.2/7.2EA−81NC 3
S332C5.2/7.2EA0*
7.2/7.2EA−23NC 2
7.2/7.2EA−23NC 2
A334C5.2/7.2EA−44NC 1
7.2/7.2EA−60NC 3
L335C7.2/7.2EA−25NC 2
7.2/7.2EAEA−25NC 3
S336C5.2/7.2EA0*
7.2/7.2EA+18+++++5–6
7.2/7.2EAEA+18+++++ 1
L338C5.2/7.2EA−29NC 3
M339C5.2/7.2EAEA0*
7.2/7.2EA+80+++++ 1
7.2/7.2EA+100+++++ 3
7.2/7.2EAEA+100+++++ 1
V340C5.2/7.2EA+20+ 8
5.2/7.2ES+15+16
A341C5.2/7.2EA−1332
V347C5.3/7.2EA−60+ 7
5.3/7.2EA−60+ 3
5.3/7.2ET−67++43
5.3/7.2ET0*
5.3/7.2ES−45+ 4
G348C5.3/7.2EA−50NC10
5.3/7.2EA−50NC 6
5.3/7.2ET−50+45
5.3/7.2ET−50+10
L350C5.3/7.2EANC++22
5.3/7.2ETNC+++48
5.3/7.2ES+10++10
V351C5.3/7.2EA−48+39
5.3/7.2ET−70+47
5.3/8.0ET−73+21
5.3/8.8ET−73+ 3
7.7/8.0ET−73+ 1
7/7.2ET−73+ 2
7/7.2ET−73+12–15
5.3/7.2ES+24+23
5.3/7.2MMTS+15NC 6
D352C5.3/7.2EA−18NCSeveral
5.3/7.2ET−27NCSeveral
5.3/7.2ES+57NCSeveral
I353C5.3/7.2EA−30NC 6
5.3/7.2EA−30NC 4
MutantpH Conditions (cis/trans)Reagents cisReagents transPercent change in conductanceΔ FlickeringNo. reactions observed
G354C5.3/7.2EA−20NC43
5.3/7.2EA−20NC 5
5.3/7.2ET−15+18
F355C5.3/7.2EA−70NC31
5.3/7.2EA−70NC 5
A356C5.3/7.2EA−46NC15
A357C5.3/7.2EANC+++Few
Y358C5.3/7.2EA−57NC 7
N359C5.3/7.2EA−64NC 8
5.3/7.2EA−64NC 7
5.3/7.2ET−75NC16
5.3/7.2ET−75NC 2
5.3/7.2MMTS−35+ 2
  •  

  • The membrane potential was held at +60 mV, except for some reactions of G348C with trans ET, which were at −60 mV. In rows where an MTS derivative is listed under both cis and trans reagents, it means the MTS derivative was added to both sides of the same membrane. EA = MTS-EA+; ET = MTS-ET+; ES = MTS-ES; MMTS = methylmethanethiosulfonate; and NC = no change.  

  • * Observed several channels for many minutes without getting any reaction.