Index.php/Sandbox Reserved 337: Difference between revisions
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{{STRUCTURE_1ztb | PDB=1ztb | SCENE=Index.php/Sandbox_Reserved_337/Aroc/1 }} | {{STRUCTURE_1ztb | PDB=1ztb | SCENE=Index.php/Sandbox_Reserved_337/Aroc/1 }} | ||
__TOC__ | __TOC__ | ||
Chorismate Synthase is the last enzyme present in the shikimate pathway<ref name= "planta"> PMID:9951731</ref>, a process which converts phosphoenolpyruvate, and erythrose 4-phosphate to chorismate in a series of seven steps.<ref name= | Chorismate Synthase is the last enzyme present in the shikimate pathway<ref name= "planta"> PMID:9951731</ref>, a process which converts phosphoenolpyruvate, and erythrose 4-phosphate to chorismate in a series of seven steps.<ref name= "review"> PMID:15012217</ref> The shikimate pathway is essential in the production of the amino acids phenylalanine, tryptophan and tyrosine, all essential amino acids.<ref name= "main"> PMID:16459102</ref> | ||
=Structure= | =Structure= | ||
This protein is in a unique form containing four subunits, and forming a homotetramer.<ref name= "pizza"> PMID:15095868</ref> The protein also contains a unique <scene name='Index.php/Sandbox_Reserved_337/Aroc2/1'>β-α-β sandwich fold</scene>.<ref name = "pizza"/> | |||
<structure load= 1um0 size=250 frame =’1’ align=’left’ caption= 'Fig. 1. Chorismate synthase complexed with FMN, from PDB [[1um0]]'/> | |||
The protein also has a cofactor bound within each monomer of the protein. This cofactor is FMN which is located within the <scene name='Index.php/Sandbox_Reserved_337/Fmn_cofactor1/1'>active site</scene> of the protein.<ref name = "pizza"/> Each of these cofactors are bound non-covalently within the protein in the reduced form.<ref name = "pizza"/> | |||
==Function== | ==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.<ref name = "planta" /> 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.<ref name ="planta" /> The enzyme is monofunctional, requiring another enzyme to reduce the flavin cofactor, or addition of extra reduced flavin to add to the enzyme.<ref name = "review" /> | |||
=Mechanism= | =Mechanism= | ||
In this reaction the 5-enolpyruvylshikimate 3-phosphate, is reduced forming a second double bond in the benzene ring attached to the phosphate.<ref name = "review" /> It appears that the phosphate group is reduced allowing the benzene ring to have a free electron pair to form a double bond with.<ref name = "review" /> As well the double bond which originally existed, experiences a hydrogen shift and the second double bond occurs to form resonance.<ref name = "review" /> | |||
=References= | =References= | ||
<references /> | <references /> | ||
