PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 8652590-3 1996 The lower axial ligand to the cobalt in free methylcobalamin is the dimethylbenzimidazole nucleotide substituent of the corrin ring; when methylcobalamin binds to methionine synthase, the ligand is replaced by histidine 759, which in turn is linked by hydrogen bonds to aspartate 757 and thence to serine 810. corrin 120-126 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 163-182 1744096-7 1991 Studies with 14 different Cbl analogues with alterations in various portions of the corrin ring and the nucleotide showed that all of the analogues were able to fully activate human methionine synthase when they were reduced with 2-mercaptoethanol. corrin 84-90 5-methyltetrahydrofolate-homocysteine methyltransferase Homo sapiens 182-201