Note. The novel amino acid sequence data published here have been submitted to the Swiss-Prot sequence data bank and are available under the accession numbers P80650–P80656 for the Mefhanosurcina mazeiN5-methyltetrahydromethanopterin: coenzyme M methyltransferase 34-, 28-, alternative 28-, 20-, 13-, 12-, and 9-kDa subunits, respectively.
Sodium Ion Translocation by N5-Methyltetrahydromethanopterin: Coenzyme M Methyltransferase from Methanosarcina mazei Gö1 Reconstituted in Ether Lipid Liposomes
Article first published online: 23 JUL 2004
European Journal of Biochemistry
Volume 239, Issue 3, pages 857–864, August 1996
How to Cite
Lienard, T., Becher, B., Marschall, M., Bowien, S. and Gottschalk, G. (1996), Sodium Ion Translocation by N5-Methyltetrahydromethanopterin: Coenzyme M Methyltransferase from Methanosarcina mazei Gö1 Reconstituted in Ether Lipid Liposomes. European Journal of Biochemistry, 239: 857–864. doi: 10.1111/j.1432-1033.1996.0857u.x
- Issue published online: 23 JUL 2004
- Article first published online: 23 JUL 2004
- (Received 14 March/l5 May 1996) – EJB 96 0370/4
- coenzyme M methyltransferase;
- ether lipid liposomes;
- sodium in translocation
The N5-methyltetrahydomethanopterin (H4MPT): coenzyme M methyltransferase is a membrane associated, corrinoid-containing protein that uses the methylation of coenzyme M (HS-CoM) by methyl-tetrahydromethanopterin to drive an energy-conserving sodium ion pump. The enzyme was purified from acetate-grown Methanosarcina mazei Göl by a two-step solubilization with η-octyl-β-glucoside, chroma-tography on hydroxyapatite, and by gel filtration on Superdex 200 or Sepharose CL-6B. The highly purified protein was apparently composed of six different subunits of 34, 28, 20, 13, 12, and 9 kDa. The N-terminal amino acid sequences of these polypeptides were determined. The native enzyme exhibited an apparent molecular mass of about 380 kDa. During purification, the enzyme was stabilized with 10 μM hydroxocobalamin. The highest specific activity reached during purification was 10.4 U/mg. The purified enzyme was reconstituted in monolayer liposomes prepared from ether lipids of M. mazei Göl. In experiments with radioactive sodium ions, it was shown that the methyltransferase catalyzes the vectorial translocation of sodium ions across the membrane. Methyltransferase activity was stimulated by sodium ions. 1.7 mol Na+/mol methyl groups transferred were translocated. Methyltetrahydrofolate and methyl-cobalamin could substitute for methyl-H4MPT.