Catalysis of the reaction: 5-methyl-5,6,7,8-tetrahydromethanopterin + coenzyme M + 2 Na+(in) = 5,6,7,8-tetrahydromethanopterin + methyl-coenzyme M + 2 Na+(out). 2-(methylthio)ethanesulfonate is also known as methyl-CoM.
N5-methyltetrahydromethanopterin--coenzyme M methyltransferase activity