The final steps of @entity815 ( @entity815 ) biosynthesis in bacteria, fungi and plants can occur via @entity34633 or @entity34632 intermediates. These routes are determined by the presence of @entity34634 dehydratase (PDT, EC4.2.1.51), which forms @entity34633 from @entity34634 , or @entity34632 dehydratase (ADT, EC4.2.1.91), which forms @entity815 directly from @entity34632 . We compared sequences from select @entity375 species to those of @entity958 . The in silico analysis showed that plant ADTs and @entity375 PDTs share many common features allowing them to act as dehydratase/decarboxylases. However, plant and @entity375 sequences clearly group independently conferring distinct substrate specificities. Complementation of the @entity375 @entity69801 mutant, which lacks PDT activity and cannot grow in the absence of exogenous @entity815 , was used to test the PDT activity of A. thaliana ADTs in vivo. Previous biochemical characterization showed that all six AtADTs had high catalytic activity with @entity34632 as a substrate, while @entity69802 , @entity69803 and @entity69804 also had limited activity with @entity34634 . Consistent with these results, the complementation test showed @entity69803 readily recovered the @entity69801 phenotype after    6 days growth at 30   C, while @entity69802 required    13 days to show visible growth. By contrast, @entity69804 (lowest PDT activity) and AtADT3-5 (no PDT activity) were unable to recover the phenotype. These results suggest that only @entity69802 and @entity69803 , but not the other four ADTs from @entity958 , have functional PDT activity in vivo, showing that there are two functional distinct groups. We hypothesize that plant ADTs have evolved to use the @entity34632 route for @entity815 synthesis while keeping some residual PDT activity.

Complementation of the @entity69801 @entity375 mutant suggests functional differences for XXXX dehydratases from @entity958 .

@entity69803 :: ('819954(Tax:3702)', 'Gene') :: ['AtADT2'] @entity34632 :: ('MESH:C015478', 'Chemical') :: ['arogenate'] @entity958 :: ('3702', 'Species') :: ['Arabidopsis thaliana', 'Arabidopsis'] @entity34633 :: ('MESH:C031606', 'Chemical') :: ['phenylpyruvate'] @entity69802 :: ('837725(Tax:3702)', 'Gene') :: ['AtADT1'] @entity815 :: ('CHEBI:28044', 'Chemical') :: ['Phe', 'phenylalanine'] @entity34634 :: ('MESH:C005550', 'Chemical') :: ['prephenate'] @entity69804 :: ('837345(Tax:3702)', 'Gene') :: ['AtADT6'] @entity375 :: ('4932', 'Species') :: ['yeast', 'Saccharomyces cerevisiae'] @entity69801 :: ('855400(Tax:4932)', 'Gene') :: ['pha2']
@entity34632 :: (MESH:C015478,Chemical) :: ['arogenate']
