1U80: Phosphopantothenoylcysteine Synthetase From E. Coli, Cmp Complex

Phosphopantothenoylcysteine (PPC) synthetase forms a peptide bond between 4'-phosphopantothenate and cysteine in coenzyme A biosynthesis. PPC synthetases fall into two classes: eukaryotic, ATP-dependent and eubacterial, CTP-dependent enzymes. We describe the first crystal structure of E. coli PPC synthetase as a prototype of bacterial, CTP-dependent PPC synthetases. Structures of the apo-form and the synthetase complexed with CTP, the activated acyl-intermediate, 4'-phosphopantothenoyl-CMP, and with the reaction product CMP provide snapshots along the reaction pathway and detailed insight into substrate binding and the reaction mechanism of peptide bond formation. Binding of the phosphopantothenate moiety of the acyl-intermediate in a cleft at the C-terminal end of the central beta sheet of the dinucleotide binding fold is accomplished by an otherwise flexible flap. A second disordered loop may control access of cysteine to the active site. The conservation of functionalities involved in substrate binding and catalysis provides insight into similarities and differences of prokaryotic and eukaryotic PPC synthetases.
PDB ID: 1U80Download
MMDB ID: 30369
PDB Deposition Date: 2004/8/4
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.85  Å
Source Organism:
Similar Structures:
Biological Unit for 1U80: dimeric; determined by author and by software (PISA)
Molecular Components in 1U80
Label Count Molecule
Proteins (2 molecules)
Coenzyme a Biosynthesis Bifunctional Protein Coabc(Gene symbol: dfp)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB