TrpEcontaining

TrpE-containing proteins are proteins that include the TrpE domain, typically the alpha subunit of anthranilate synthase, a key enzyme in the tryptophan biosynthesis pathway. The TrpE domain is found in many bacterial proteins and in plant and fungal orthologs as part of the anthranilate synthase complex, which usually functions with a TrpG beta subunit.

In bacteria, the genes encoding TrpE and TrpG are often co-regulated and may reside in operons dedicated to tryptophan production. Some TrpE-containing proteins are single polypeptides with fused domains in certain lineages, reflecting domain shuffling and regulatory innovations.

Function and mechanism: Anthranilate synthase catalyzes the first committed step in tryptophan biosynthesis, converting chorismate to anthranilate. It is a glutamine amidotransferase, composed of TrpE (alpha) and TrpG (beta) subunits; TrpG provides ammonia derived from glutamine, enabling the TrpE-catalyzed reaction.

Distribution and regulation: TrpE-containing proteins are widespread in bacteria and are present in chloroplasts of plants and algae, where tryptophan biosynthesis occurs. Expression is often subject to feedback regulation by tryptophan via operon attenuation or repressors in bacteria.

In annotation and research, TrpE-containing entries denote proteins that bear the TrpE domain; functional inferences are made based on this domain and accompanying subunits, though experimental validation may vary. Studying TrpE-containing proteins can illuminate evolutionary history of tryptophan biosynthesis and operon organization.