Chorismate lyase

In enzymology, a chorismate lyase (EC 4.1.3.40) is an enzyme that catalyzes the chemical reaction

chorismate 4-hydroxybenzoate + pyruvate

The chorismate pyruvate lyase (CPL) catalyzed reaction.

Hence, this enzyme has one substrate, chorismate, and two products, 4-hydroxybenzoate and pyruvate.

This enzyme belongs to the family of lyases, specifically the oxo-acid-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is chorismate pyruvate-lyase (4-hydroxybenzoate-forming). Other names in common use include CL, CPL, and UbiC.

This enzyme catalyses the first step in ubiquinone biosynthesis, the removal of pyruvate from chorismate, to yield 4-hydroxybenzoate in Escherichia coli and other Gram-negative bacteria.^[1] Its activity does not require metal cofactors.^[2]

== Activity^[3]

Chorismate lyase
chorismate lyase with product, 1.0 a resolution
Identifiers
Symbol	Chor_lyase
Pfam	PF04345
Pfam clan	CL0122
InterPro	IPR007440
SCOP	1jd3
SUPERFAMILY	1jd3
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Catalytic activity

• Chorismate = 4HB + pyruvate^[4]
• This enzyme has an optimum pH at 7.5

Enzymatic activity

Inhibited by:

• Vanillate
• 4-hydroxybenzaldehyde
• 3-carboxylmethylaminmethyl-4-hydroxybenzoic acid
• 4HB - ubiC is inhibited by the product of the reaction, which scientists believe serves as a control mechanism for the pathway

Pathway

The pathway used is called the ubiquinone biosynthesis pathway, it catalyzes the first step in the biosynthesis of ubiquinone in E. coli. Ubiquinone is a lipid-soluble electron-transporting coenzyme. They are essential electron carriers in prokaryotes and are essential in aerobic organisms to achieve ATP.

Nomenclature^[3]

There are several different names for chorismate lyase. it is also called chorismate pyruvate lyase (4-hydroxybenzoate-forming) and it is also abbreviated several different ways: CPL, CL, and ubiC. It is sometimes referred to as ubiC, because that is the gene name. This enzyme belongs to the class Lyases; more specifically the ox-acid-lyase or the carbon-carbon-lyases.

• • taxonomic lineage: bacteria → proteobacteria → gammaproteobacteria → enterobacteriales → enterobacteriaceae → escherichia → escherichia coli

Structure^[3]

This enzyme is a monomer. Its secondary structure contains helixes, turns, and beta strands.

• It has a mass of 18,777 daltons
• Its sequence is 165 amino acids long

Binding Sites

• position: 35(M)
• position: 77(R)
• position: 115(L)

Mutagenesis^[3]

• position: 91- G → A; increases product inhibition by 40%. No effect on substrate affinity.
• position: 156 - E → K; loss of activity

References

Further reading

• Nichols BP, Green JM (1992). "Cloning and sequencing of Escherichia coli ubiC and purification of chorismate lyase". J. Bacteriol. 174 (16): 5309–16. PMC 206367. PMID 1644758. 
• Siebert M, Severin K, Heide L. "Formation of 4-hydroxybenzoate in Escherichia coli: characterization of the ubiC gene and its encoded enzyme chorismate pyruvate-lyase". Microbiology. 140 (4): 897–904. doi:10.1099/00221287-140-4-897. PMID 8012607. 
• Meganathan R (2001). "Ubiquinone biosynthesis in microorganisms". FEMS Microbiol. Lett. 203 (2): 131–9. doi:10.1111/j.1574-6968.2001.tb10831.x. PMID 11583838. 

This article incorporates text from the public domain Pfam and InterPro IPR007440