Open AccessThe transmembrane electrochemical gradient of Na + as driving force for methanol oxidation in Methanosarcina barkeri
Author(s) -
MÜLLER Volker,
BLAUT Michael,
GOTTSCHALK Gerhard
Publication year - 1988
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1988.tb13931.x
Subject(s) - methanosarcina barkeri , methanogenesis , monensin , methanol , chemistry , amiloride , antiporter , electrochemical gradient , sodium , methanosarcina , inorganic chemistry , ionophore , nuclear chemistry , membrane , methane , biochemistry , organic chemistry
A sodium ion gradient (inside low) across the cytoplasmic membrane of Methanosarcina barkeri was required for methanogenesis from methanol. This could be concluded from the following results. (a) Inhibition of the Na + /H + antiporter by K + or amiloride led to an inhibition of methanogenesis from methanol. (b) Upon addition of the sodium ionophore monensin the Na + gradient was abolished and at the same time methanogenesis from methanol was inhibited. (c) Methanogenesis was impaired when the Na + gradient had the opposite orientation (inside high). All these inhibitory effects were not observed when H 2 was present in addition to methanol indicating that the oxidation of methanol to CO 2 was driven by a sodium‐motive force. In accordance with this, a methanol‐dependent influx of Na + and a corresponding decrease of the membrane potential could be observed, when the Na + /H + antiporter was inhibited by amiloride. This influx was indicative of the presence of a Na + transport system which was functional when the oxidation of methanol had to be driven, but was not functional when H 2 was present for reduction of methanol to methane.