Cofactors

There are no Cofactors for this Enzyme

Reaction Mechanism

phosphopantothenate-cysteine ligase By Reference

Phosphopantothenoylcysteine (PPC) synthase is a CTP-dependent enzyme joining L-cysteine to 4'-phosphopantothenate via a peptide bond. This reaction is part of the coenzyme A biosynthesis pathway. In E. coli, PPC synthase activity is performed by the CoaB domain of the bifunctional Dfp protein, with the next step of decarboxylation performed by the CoaC domain. Both domains have catalytic activity on their own.




Much of the catalytic role of PPC synthase is due to the binding of substrates in the correct positions for reaction. The first half of the reaction attaches CMP onto phosphopantothenate. The carboxylate group of pantothenate is nucleophilic and attacks the alpha-phosphate of CTP (probably activated as an electrophile by coordination to a magnesium ion). Diphosphate is the leaving group, and the activated intermediate 4'-phosphopantothenoyl-CMP is formed. L-cysteine can now bind and its amino group attacks the carbonyl carbon of the ester group. This forms a tetrahedral transition state; the developing negative charge on the carbonyl oxygen is stabilised by a water molecule held by Asn 210. The transition state collapses to form CMP and the product.

Catalytic Residues

AA	Uniprot	Uniprot Resid	PDB	PDB Resid
Asn	P0ABQ0	210	1u7u	30
View Reaction Mechanisms in M-CSA

Reaction Parameters

There are no kinetic parameters information for this Enzyme

Associated Proteins

Citations

• In Silico Probiogenomic Characterization of Lactobacillus delbrueckii subsp. lactis A4 Strain Isolated from an Armenian Honeybee Gut.
• Evaluating the Genetic Capacity of Mycoplasmas for Coenzyme A Biosynthesis in a Search for New Anti-mycoplasma Targets.
• In Vitro Production of Coenzyme A Using Thermophilic Enzymes.
• Sodium Fluoride Exposure Leads to ATP Depletion and Altered RNA Decay in Escherichia coli under Anaerobic Conditions.
• Mining the Flavoproteome of Brucella ovis, the Brucellosis Causing Agent in Ovis aries.
• Multitargeting Compounds: A Promising Strategy to Overcome Multi-Drug Resistant Tuberculosis.
• Characterization and validation of Entamoeba histolytica pantothenate kinase as a novel anti-amebic drug target.
• Metabolic network analysis-based identification of antimicrobial drug targets in category A bioterrorism agents.
• The search for novel treatment strategies for Streptococcus pneumoniae infections.
• Novel insights into plant-associated archaea and their functioning in arugula (Eruca sativa Mill.).
• Profiling protein kinases and other ATP binding proteins in Arabidopsis using Acyl-ATP probes.