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SLIDE SHOW IWild-type mechanism
K319
-
-+
-+
C
E325
H322
D240R
E126
148144
IV
VIIV
-E269
VIII
+R302
IX
X
A. In the ground state the permease is protonated
H+
K319
-
+
-+
C
E325
H322
D240R148144 -
E126
IV
VIIV
-E269
VIII
+R302
IX
X
B. Substrate binds from the outside
H+o
So
K319
-
-+
-+
C
E325
H322
D240R
E126
148144
IV
VIIV
-E269
VIII
+R302
IX
X
So
C. Binding of substrate causes a conformational change disrupting the interaction of Glu269 and His322 and ….
H+
+
-+CR
R302
E126
148144
IV
VIIV
IX
-
D240
-
E 325
H 322
K 319
+
X
-
E269
VIII
Si
D. ... causes substrate to become accessible to the internal surface, and the proton moves to His322/Glu325.
H+
+
-+CR
R302
E126
148144
IV
VIIV
IX
-
D240
-
E 325
H 322
K 319
+
X
-
E269
VIII
Si
E. Rotation of Helix X continues towards the hydrophobic phase of the membrane,
H+
+
-+CR
R302
E126
148144
IV
VIIV
IX
-
D240
-E 325H
322K
319
+
X
-
E269
VIII
Si
F. raising the pKa of Glu325.
H+
+
+CR
R302
148144
IV
V
IX
-
-
E126
VIID240
-E 325H
322K
319
+
X
-
E269
VIII
G. Substrate dissociates to the inside,
H+
Si
Si
H. And Glu325 re-juxtaposes with Arg302.
+
-+CR
R302
E126
148144
IV
VIIV
IX
-
D240
-E 325H
322K
319
+
X
-
E269
VIII
H+
K319
-
+
-+
C
E325
H322
D240R148144 -
E126
IV
VIIV
-E269
VIII
+R302
IX
X
I. The proton is released to the inside,
H+i
K319
-
-+
-+
C
E325
H322
D240R
E126
148144
IV
VIIV
-E269
VIII
+R302
IX
X
J. the permease relaxes into the ground state and becomes protonated from the outside.
H+o
N7C5
C5
_+ + + +
_ _ _
MT
S-1
-MT
S
MT
S-3
-MT
S
o-P
DM
p-P
DM
TDGno
lin
ker
K. Crosslinking between Asp240 (helix VII) and Lys319 (helix X): Effect of ligand binding
MTS-1-MTS: 3 ÅMTS-3-MTS: 5 Å; flexibleo-PDM: 6 Å; rigidp-PDM: 10 Å; rigid