Phosphoenolpyruvate---protein phosphotransferase
Phosphoenolpyruvate-protein phosphotransferase, (PTS enzyme I), is a component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (sugar PTS). PTS catalyses the phosphorylation of incoming sugar substrates concomitantly with their translocation across the cell membrane. PTS enzyme I transfers the phosphoryl group from phosphoenolpyruvate to the phosphoryl carrier protein HPr [PMID:9922238].
Reference Protein and Structure
- Sequence
-
P08839
(2.7.3.9)
(Sequence Homologues)
(PDB Homologues)
- Biological species
-
Escherichia coli K-12 (Bacteria)
- PDB
-
2hwg
- Structure of phosphorylated Enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system
(2.7 Å)
- Catalytic CATH Domains
-
3.20.20.60
3.50.30.10
(see all for 2hwg)
- Cofactors
- Magnesium(2+) (1)
Enzyme Reaction (EC:2.7.3.9)
+
→
+
Alternative enzyme names: Phosphoenolpyruvate:protein-L-histidine N-pros-phosphotransferase, Phosphoenolpyruvate sugar phosphotransferase enzyme I, Phosphopyruvate--protein factor phosphotransferase, Phosphopyruvate--protein phosphotransferase, Sugar--PEP phosphotransferase enzyme I, Phosphoenolpyruvate--protein phosphatase, Enzyme I of the phosphotransferase system,
Enzyme Mechanism
Introduction
The reaction follows an in-line phosphotransfer mechanism involving pentacoordinated phosphorous with trigonal bipyramidal geometry, and the donor (PEP) and acceptor (His-189 in EI) in the apical positions. The pyruvyl enolate product is protonated by Cys502.
Catalytic Residues Roles
| UniProt | PDB* (2hwg) | ||
| His189 | Nep189A | This histidine residue acts as a catalytic nucleophile to become phosphorylated during the course of the reaction. | covalent catalysis |
| Cys502 | Cys502A | Acts as an acid-base catalyst which stereospecifically protonates the pyruvoyl enolate at C3. | proton shuttle (general acid/base) |
| Glu431, Asp455 | Glu431A, Asp455A | Forms part of the magnesium binding site. | metal ligand |
*PDB label guide - RESx(y)B(C) - RES: Residue Name; x: Residue ID in PDB file;
y: Residue ID in PDB sequence if different from PDB file; B: PDB Chain;
C: Biological Assembly Chain if different from PDB. If label is "Not Found" it means this residue is not found in the reference PDB.
Chemical Components
References
- Teplyakov A et al. (2006), Proc Natl Acad Sci U S A, 103, 16218-16223. Structure of phosphorylated enzyme I, the phosphoenolpyruvate:sugar phosphotransferase system sugar translocation signal protein. DOI:10.1073/pnas.0607587103. PMID:17053069.
- Oberholzer AE et al. (2009), J Biol Chem, 284, 33169-33176. Crystal structure of enzyme I of the phosphoenolpyruvate sugar phosphotransferase system in the dephosphorylated state. DOI:10.1074/jbc.M109.057612. PMID:19801641.
- García-Alles LF et al. (2003), Biochemistry, 42, 4744-4750. Enzyme I of the phosphotransferase system: induced-fit protonation of the reaction transition state by Cys-502. DOI:10.1021/bi034007f. PMID:12705838.
- Garcia-Alles LF et al. (2002), J Biol Chem, 277, 6934-6942. Mechanism-based inhibition of enzyme I of the Escherichia coli phosphotransferase system. Cysteine 502 is an essential residue. DOI:10.1074/jbc.M110067200. PMID:11741915.
- Ginsburg A et al. (2000), Protein Sci, 9, 1085-1094. Conformational stability changes of the amino terminal domain of enzyme I of the Escherichia coli phosphoenolpyruvate: sugar phosphotransferase system produced by substituting alanine or glutamate for the active-site histidine 189: implications for phosphorylation effects. DOI:10.1110/ps.9.6.1085. PMID:10892802.
- Luesink EJ et al. (1999), J Bacteriol, 181, 764-771. Molecular characterization of the Lactococcus lactis ptsHI operon and analysis of the regulatory role of HPr. PMID:9922238.
- Garrett DS et al. (1998), Protein Sci, 7, 789-793. Tautomeric state and pKa of the phosphorylated active site histidine in the N-terminal domain of enzyme I of the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system. DOI:10.1002/pro.5560070329. PMID:9541412.
- Liao DI et al. (1996), Structure, 4, 861-872. The first step in sugar transport: crystal structure of the amino terminal domain of enzyme I of the E. coli PEP: sugar phosphotransferase system and a model of the phosphotransfer complex with HPr. DOI:10.1016/s0969-2126(96)00092-5. PMID:8805571.
Catalytic Residues Roles
| Residue | Roles |
|---|---|
| Cys502A | proton shuttle (general acid/base) |
| Nep189A | covalent catalysis |
| Glu431A | metal ligand |
| Asp455A | metal ligand |