Premium
Solution structure of the N‐terminal amphitropic domain of Escherichia coli glucose‐specific enzyme IIA in membrane‐mimetic micelles
Author(s) -
Wang Guangshun,
Keifer Paul A.,
Peterkofsky Alan
Publication year - 2003
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0301503
Subject(s) - chemistry , micelle , peptide , membrane , circular dichroism , pep group translocation , crystallography , escherichia coli , stereochemistry , protein secondary structure , nuclear magnetic resonance spectroscopy , enzyme , biochemistry , aqueous solution , phosphoenolpyruvate carboxykinase , organic chemistry , gene
The N‐terminal domain of enzyme IIA Glc of the Escherichia coli phosphoenolpyruvate:sugar phosphotransferase system confers amphitropism to the protein, allowing IIA Glc to shuttle between the cytoplasm and the membrane. To further understand this amphitropic protein, we have elucidated, by NMR spectroscopy, the solution structure of a synthetic peptide corresponding to the N‐terminal domain of IIA Glc . In water, this peptide is predominantly disordered, consistent with previous data obtained in the absence of membranes. In detergent micelles of dihexanoylphosphatidylglycerol (DHPG) or sodium dodecylsulfate (SDS), however, residues Phe 3–Val 10 of the peptide adopt a helical conformation in the ensemble of structures calculated on the basis of NOE‐derived distance restraints. The root mean square deviations for superimposing the backbone atoms of the helical region are 0.18 Å in DHPG and 0.22 Å in SDS. The structure, chemical shifts, and spin–spin coupling constants all indicate that, of the four lysines in the N‐terminal domain of IIA Glc , only Lys 5 and Lys 7 in the amphipathic helical region interact with DHPG. In addition, the peptide‐detergent interactions were investigated using intermolecular NOESY experiments. The aliphatic chains of anionic detergents DHPG, SDS, and 2,2‐dimethyl‐2‐silapentane‐5‐sulfonate sodium salt (DSS) all showed intermolecular NOE cross‐peaks to the peptide, providing direct evidence for the putative membrane anchor of IIA Glc in binding to the membrane‐mimicking micelles.