Acetyl-CoA carboxylase is found in all animals, plants, and bacteria and catalyzes the first committed step in fatty acid synthesis. It is a multicomponent enzyme containing a biotin carboxylase activity, a biotin carboxyl carrier protein, and a carboxyltransferase functionality. The "B-domain" extends from the main body of the subunit where it folds into two α-helical regions and three … expand

Acetyl-CoA carboxylase is found in all animals, plants, and bacteria and catalyzes the first committed step in fatty acid synthesis. It is a multicomponent enzyme containing a biotin carboxylase activity, a biotin carboxyl carrier protein, and a carboxyltransferase functionality. The "B-domain" extends from the main body of the subunit where it folds into two α-helical regions and three strands of β-sheet. Following the excursion into the B-domain, the polypeptide chain folds back into the body of the protein where it forms an eight-stranded antiparallel β-sheet. In addition to this major secondary structural element, the C-terminal domain also contains a smaller three-stranded antiparallel β-sheet and seven α-helices [ PUBMED:7915138 ].