TY  - JOUR
A1  - Hoppe, J.
A1  - Friedl, P.
A1  - Schairer, H. U.
A1  - Sebald, Walter
A1  - Meyenburg, K. von
A1  - Jorgensen, B. B.
T1  - The topology of the proton translocating F\(_0\) component of the ATP synthase from E. coli K12: studies with proteases
N2  - The accessibility of the three F\(_0\) subunits a, b and c from the Escherichia coli Kll A TP synthase to various proteases was studied in F\(_1\)-depleted inverted membrane vesicles. Subunit b was very sensitive to all applied proteases. Chymotrypsin produced a defined fragment of mol. wt. 1S 000 which remained tightly bound to the membrane. The cleavage site was located at the C-terminal region of subunit b. Larger amounts of proteases were necessary to attack subunit a (mol. wt. 30 000). There was no detectable deavage of subunit c. It is suggested that the major hydrophilic part of subunit b extends from the membrane into the cytoplasm and is in contact with the F\(_1\) sector. The F\(_1\) sector was found to afford some protection against proteolysis oftheb subunit in vitro andin vivo. Protease digestion bad no influence on the electro-impelled H\(^+\) conduction via F\(_0\) bot ATP-dependent H\(^+\) translocation could not be reconstituted upon binding of F\(_1\)• A possible role for subunit b as a linker between catalytic events on the F\(_1\) component and the proton pathway across the membrane is discussed.
KW  - Biochemie
KW  - protein pathway
KW  - ATPase mutants
Y1  - 1983
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62718
ER  -