Tautomeric state and pK a of the phosphorylated active site histidine in the N‐terminal domain of enzyme I of the Escherichia coli phosphoenolpyruvate: Sugar phosphotransferase system
| Autor: | G. M. Clore, Yeong-Jae Seok, D.S. Garrett, Alan Peterkofsky, Angela M. Gronenborn |
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| Rok vydání: | 1998 |
| Předmět: |
Models
Molecular Binding Sites biology Stereochemistry Chemistry Active site Protonation PEP group translocation Biochemistry Tautomer Protein Structure Tertiary Bacterial Proteins Escherichia coli biology.protein Histidine Phosphorylation Binding site Phosphoenolpyruvate Sugar Phosphotransferase System Phosphoenolpyruvate carboxykinase Nuclear Magnetic Resonance Biomolecular Molecular Biology Conformational isomerism Research Article |
| Zdroj: | Protein Science. 7:789-793 |
| ISSN: | 1469-896X 0961-8368 |
| Popis: | The phosphorylated form of the N-terminal domain of enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system of Escherichia coli has been investigated by one-bond and long-range 1H-15N correlation spectroscopy. The active site His 189 is phosphorylated at the Nepsilon2 position and has a pKa of 7.3, which is one pH unit higher than that of unphosphorylated His 189. Because the neutral form of unphosphorylated His 189 is in the Ndelta1-H tautomer, and its Nepsilon2 atom is solvent inaccessible and accepts a hydrogen bond from the hydroxyl group of Thr 168, both protonation and phosphorylation of His 189 must be accompanied by a change in the side-chain conformation of His 189, specifically from a chi(2) angle in the g+ conformer in the unphosphorylated state to the g- conformer in the phosphorylated state. |
| Databáze: | OpenAIRE |
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