passages.id: split_6_test_3463_passage
passages.type: progene_text
passages.text: The structures reveal the characteristic fold that binds thiamine diphosphate and resemble closely the alpha(2)beta(2) hetero - tetrameric E1 components of other 2-oxo acid dehydrogenase complexes , except that in E1o , the alpha and beta subunits are fused as a single polypeptide .