Tryptophan synthase beta chain/beta chain-like (IPR023026)

Short name: Trp_synth_beta/beta-like

Overlapping homologous superfamilies

Family relationships


Tryptophan synthase catalyzes the last step in the biosynthesis of tryptophan [PMID: 2679363, PMID: 1366510]: L-serine + 1-(indol-3-yl)glycerol 3-phosphate = L-tryptophan + glyceraldehyde 3-phosphate + H2O It has two functional domains, each found in bacteria and plants on a separate subunit: alpha chain (IPR002028) is for the aldol cleavage of indoleglycerol phosphate to indole and glyceraldehyde 3-phosphate and beta chain is for the synthesis of tryptophan from indole and serine. In fungi the two domains are fused together on a single multifunctional protein [PMID: 2734310].

The beta chain of the enzyme, represented here, requires pyridoxal-phosphate as a cofactor. The pyridoxal-phosphate group is attached to a lysine residue. The region around this lysine residue also contains two histidine residues which are part of the pyridoxal-phosphate binding site.

This entry also contains sequences that represent a family of pyridoxal-phosphate dependent enzymes that are closely related to the beta subunit of tryptophan synthase. However, the only case in which a member of this family replaces a member of TIGR00263 is in Sulfolobus species which contain two sequences which hit this model, one of which is proximal to the alpha subunit. In every other case so far, either the species appears not to make tryptophan (there is no trp synthase alpha subunit), or a trp synthase beta subunit matching TIGR00263 is also found.

GO terms

Biological Process

GO:0000162 tryptophan biosynthetic process

Molecular Function

GO:0004834 tryptophan synthase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.