S-adenosyl-L-methionine dependent methyltransferase that catalyzes the methylation of tellurite and is responsible for tellurite resistance when present in high copy number. Can also methylate selenite and selenium dioxide. Is thus able to detoxify different chalcogens. Cannot methylate arsenic compounds. S-adenosyl-L-methionine + tellurite = methanetellurite + S-adenosyl-L-homocysteine Homodimer. Probably a peripheral membrane protein that interacts with TehA. Belongs to the TehB family. Was originally thought to be plasmid encoded.