Sandbox Reserved 325: Difference between revisions

Chorismate mutase is a homodimer which has an all-α-helical structure <ref name="pizza" />.  There are 10 α-helices spread across the two monomers of chorismate mutase <ref name="pizza" />.  Approximately 86% of the amino acid residues are in the α-helical formations <ref name="pizza" />.  The α-helical structure of ''M. tuberculosis'' chorismate mustase similar to the chorismate mutases of ''S. cerevisae'' and ''E. coli'' < ref name="pizza" />.  It holds its dimeric state in a protein concentration as low as 5 nM <ref name="pizza" />. There are no β-sheets present in chorismate mutase <ref name="CMArt2" />  

Chorismate has an active site, which is used for the catalysis of the shikimate pathway <ref name="pizza" />.  The active site is made of Arg ₄₉,Lys ₆₀, Arg ₇₂, Thr ₁₀₅, Glu ₁₀₉, and Arg ₁₃₄<ref name="pizza" />. This active site exists through electrostatic interactions with chorismate and hydrogen bonding between the amino acids <ref name="CMW2" />.  The active site forms within a single chain <ref name="pizza" />.  The active site can form without any help from the second half of the dimer <ref name="pizza" />.

The molecular weight of chorismate mutase is 36,000 Da <ref name="pizza" />.  Based on the fact that each monomeric subunit has a molecular weight of 18,474 Da, the molecular weight of the molecule supports the theory that it is a dimer <ref name="pizza" />.  This is also supported by the fact that all chorismate mutases that occur naturally are either trimers or dimers <ref name="pizza" />   

There are no allosteric regulatory sites on chorismate mutase, which supports the theory that it is not regulated by the aromatic amino acids that are the products of the shikimate pathway < ref name="pizza" />.