We have investigate
d the possibility of cell-fee synthesis of membrane proteins in the absenceof a membrane an
d in the presence of
detergent. We use
d the bacterial mechanosensitive channel MscL,a homopentamer, as a mo
del protein. A wi
de range of nonionic or zwitterionic
detergents, Triton X-100,Tween 20, Brij 58p,
n-
do
decyl
![](/images/gifchars/beta2.gif)
ddle">-
D-maltosi
de, an
d CHAPS, were compatible with cell-free synthesis,while
n-octyl
![](/images/gifchars/beta2.gif)
ddle">-
D-glucosi
de an
d deoxycholate ha
d an inhibitory effect. In vitro synthesis in the presenceof Triton X-100 yiel
de
d milligram amounts of MscL per milliliter of lysate. Cross-linking experimentsshowe
d that the protein was able to oligomerize in
detergents. When the purifie
d protein was reconstitute
din liposomes an
d stu
die
d by the patch-clamp technique, its activity at the single-molecule level was similarto that of the recombinant protein pro
duce
d in
Escherichia coli. Cell-free synthesis of membrane proteinsshoul
d prove a valuable tool for the pro
duction of membrane proteins whose overexpression in heterologoussystems is
difficult.