This entry represents the CM type 2 domain, mainly from prokaryotes. It does not include the CM from plants and or Baker's yeast.

Chorismate mutase (CM) is a regulatory enzyme ( EC:5.4.99.5 ) required for biosynthesis of the aromatic amino acids phenylalanine and tyrosine. CM catalyzes the Claisen rearrangement of chorismate … expand

This entry represents the CM type 2 domain, mainly from prokaryotes. It does not include the CM from plants and or Baker's yeast.

Chorismate mutase (CM) is a regulatory enzyme ( EC:5.4.99.5 ) required for biosynthesis of the aromatic amino acids phenylalanine and tyrosine. CM catalyzes the Claisen rearrangement of chorismate to prephenate, which can subsequently be converted to precursors of either L-Phe or L-Tyr. In bifunctional enzymes the CM domain can be fused to a prephenate dehydratase (P-protein for Phe biosynthesis), to a prephenate dehydrogenase (T-protein, for Tyr biosynthesis), or to 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase. Besides these prokaryotic bifunctional enzymes, monofunctional CMs occur in prokaryotes as well as in fungi, plants and nematode worms [ PUBMED:11528003 ]. The sequence of monofunctional chorismate mutase aligns well with the N-terminal part of P-proteins [ PUBMED:9642265 ].

The type II or AroQ class of CM has an all-helical 3D structure, represented by the CM domain of the bifunctional Escherichia coli P-protein. This type is named after the Enterobacter agglomerans monofunctional CM encoded by the aroQ gene [ PUBMED:8335631 ]. All CM domains from bifunctional enzymes as well as most monofunctional CMs belong to this class, including archaeal CM.

Eukaryotic CM from plants and fungi form a separate subclass of AroQ, represented by the Baker's yeast allosteric CM. These enzymes show only partial sequence similarity to the prokaryotic CMs due to insertions of regulatory domains, but the helix-bundle topology and catalytic residues are conserved and the 3D structure of the E. coli CM dimer resembles a yeast CM monomer [ PUBMED:11528003 PUBMED:9384560 PUBMED:9665711 ]. The E. coli P-protein CM domain consists of 3 helices and lacks allosteric regulation. The yeast CM has evolved by gene duplication and dimerization and each monomer has 12 helices. Yeast CM is allosterically activated by Trp and inhibited by Tyr [ PUBMED:9384560 ].