The TyrA family includes enzymes with four specificities for the cyclohexadiencyl substrate. PapC participates in antibiotic synthesis and utilizes the 4-amino derivative of prephenate (PPA) as substrate. It can be recognized by its lack of an otherwise invariant residue that interacts with the 4-hydroxy substituent of the cyclohexadienyl substrate in the other three classes. The remaining three classes are alternative dehydrogenase reactions of TYR biosynthesis. TyrAa and TyrAp are specific for AGN and PPA, respectively. TyrAc enzymes have broad specificity and can recognize both AGN and PPA to various extents. A distinct variation of the TyrAc class, denoted as TyrAc_Δ, possesses deletion indels within the catalytic core region. Members of the known substrate-specificity types do not separate into cohesive phylogenetic subgroups, and no obvious discriminating motifs have been found. However, profile HMMs that are provided as a tool here have tentative value for prediction of substrate specificity. These HMMs were trained with our collection of curated cyclohexadienyl-substrate core segments as seed sequences that belong to known cyclohexadienyl-substrate classes.

Here we provide (1) the multiple sequence alignments of catalytic core seed sequences for each subfamily and the combined sequences using HMMALIGN, (2) the tool to allow users to generate new alignment with a subset of sequences of interest and the corresponding phylogenetic tree using ANCESCON.

TyrAa	----	Arogenate dehydrogenase (ADH)
TyrAc	----	Cyclohexadienyl dehydrogenase (CDH)
TyrAp	----	Prephenate dehydrogenase (PDH)
TyrAc_Δ	----	A broad-specificity tyrosine-pathway cyclohexadienyl dehydrogenase (CDH) in which the presence of indel deletions within the catalytic core region correlates with the existence of extra-core extension resides.
TyrA	----	TyrA protein family (including all four subfamilies listed above)