Index.php/Sandbox Reserved 337

From Proteopedia

Jump to: navigation, search

Chorismate synthase

PDB ID 1ztb

Drag the structure with the mouse to rotate
1ztb, resolution 2.65Å ()
Gene: aroC, aroF (Mycobacterium tuberculosis)
Activity: Chorismate synthase, with EC number 4.2.3.5
Resources: FirstGlance, OCA, RCSB, PDBsum
Coordinates: save as pdb, mmCIF, xml


Contents

Chorismate Synthase is the last enzyme present in the shikimate pathway[1], a process which converts phosphoenolpyruvate, and erythrose 4-phosphate to chorismate in a series of seven steps.[2] The shikimate pathway is essential in the production of the amino acids phenylalanine, tryptophan and tyrosine, all essential amino acids.[3]

Structure

This protein is in a unique form containing four subunits, and forming a homotetramer.[4] The protein also contains a unique .[4]

Fig. 1. Chorismate synthase complexed with FMN, from PDB 1um0

Drag the structure with the mouse to rotate

The protein also has a cofactor bound within each monomer of the protein. This cofactor is FMN which is located within the of the protein.[4] Each of these cofactors are bound non-covalently within the protein in the reduced form.[4]

Function

The purpose of chorismate synthase is to convert 5-enolpyruvylshikimate 3-phosphate to chorismate, an essential step in the formation of indole rings used in the essential amino acids phenylalanine, tyrosine, and tryptophan.[1] The reduced flavin is believed to have one of a couple functions. It either has a structural role helping with formation of the structure, or reduces a sulfhydryl group in the protein residue, either aiding with binding or with having a catalytic effect.[1] The enzyme is monofunctional, requiring another enzyme to reduce the flavin cofactor, or addition of extra reduced flavin to add to the enzyme.[2]

Mechanism

In this reaction the 5-enolpyruvylshikimate 3-phosphate, is reduced forming a second double bond in the benzene ring attached to the phosphate.[2] It appears that the phosphate group is reduced allowing the benzene ring to have a free electron pair to form a double bond with.[2] As well the double bond which originally existed, experiences a hydrogen shift and the second double bond occurs to form resonance.[2]

References

  1. ↑ 1.0 1.1 1.2 Macheroux P, Schmid J, Amrhein N, Schaller A. A unique reaction in a common pathway: mechanism and function of chorismate synthase in the shikimate pathway. Planta. 1999 Jan;207(3):325-34. PMID:9951731
  2. ↑ 2.0 2.1 2.2 2.3 2.4 Herrmann KM, Weaver LM. THE SHIKIMATE PATHWAY. Annu Rev Plant Physiol Plant Mol Biol. 1999 Jun;50:473-503. PMID:15012217 doi:10.1146/annurev.arplant.50.1.473
  3. ↑ Dias MV, Borges JC, Ely F, Pereira JH, Canduri F, Ramos CH, Frazzon J, Palma MS, Basso LA, Santos DS, de Azevedo WF Jr. Structure of chorismate synthase from Mycobacterium tuberculosis. J Struct Biol. 2006 May;154(2):130-43. Epub 2006 Jan 17. PMID:16459102 doi:10.1016/j.jsb.2005.12.008
  4. ↑ 4.0 4.1 4.2 4.3 Ahn HJ, Yoon HJ, Lee B 2nd, Suh SW. Crystal structure of chorismate synthase: a novel FMN-binding protein fold and functional insights. J Mol Biol. 2004 Feb 27;336(4):903-15. PMID:15095868

Proteopedia Page Contributors and Editors (what is this?)

Craig Murray, Andrea Gorrell

Retrieved from "http://52.214.119.220/wiki/index.php/Index.php/Sandbox_Reserved_337"
Personal tools