page_title: Chorismate synthase
section_title: Structural studies
hierarchical_section_title: Chorismate synthase / Structural studies
caption_attribution_description: English: Chorismate synthase showing only one of the four monomers that combine to form the molecule. FMN is shown in red interacting with the molecule.
context_page_description: In enzymology, a chorismate synthase is an enzyme that catalyzes the chemical reaction
  5-O--3-phosphoshikimate chorismate + phosphate
  Hence, this enzyme has one substrate, 5-O--3-phosphoshikimate, and two products, chorismate and phosphate.
  This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is 5-O--3-phosphoshikimate phosphate-lyase. This enzyme is also called 5-O--3-phosphoshikimate phosphate-lyase. This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis.
  Chorismate synthase catalyzes the last of the seven steps in the shikimate pathway which is used in prokaryotes, fungi and plants for the biosynthesis of aromatic amino acids. It catalyzes the 1,4-trans elimination of the phosphate group from 5-enolpyruvylshikimate-3-phosphate to form chorismate which can then be used in phenylalanine, tyrosine or tryptophan biosynthesis. Chorismate synthase requires the presence of a reduced flavin mononucleotide for its activity. Chorismate synthase from various sources shows a high degree of sequence conservation. It is a protein of about 360 to 400 amino-acid residues.
context_section_description: As of late 2007, 9 structures have been solved for this class of enzymes, with PDB accession codes 1Q1L, 1QXO, 1R52, 1R53, 1SQ1, 1UM0, 1UMF, 1ZTB, and 2G85.
  The crystal structure of chorismate synthase is a homotetramer with one
  FMN molecule non-covalently bound to each of the four monomers.  
  Each monomer is made up of 9 alpha helices and 18 beta strands and the core 
  is assembled in a unique beta-alpha-beta sandwich fold. The active sites for FMN-binding are made up of clusters of flexible loops and the area around these regions have highly positive electromagnetic potential. There are two histidine residues located at the active site which are thought to protonate the reduced flavin molecule and the leaving phosphate group of the substrate.
caption: shows one of the four monomers that make up the active chorismate synthase molecule interacting with the FMN molecule in Mycobacterium tuberculosis
exif: {}