PMID:14744128
| Citation |
Tafer, H, Hiller, S, Hilty, C, Fernández, C and Wüthrich, K (2004) Nonrandom structure in the urea-unfolded Escherichia coli outer membrane protein X (OmpX). Biochemistry 43:860-9 |
|---|---|
| Abstract |
On the basis of sequence-specific resonance assignments for the complete polypeptide backbone and most of the amino acid side chains by heteronuclear nuclear magnetic resonance (NMR) spectroscopy, the urea-unfolded form of the outer membrane protein X (OmpX) from Escherichia coli has been structurally characterized. (1)H-(1)H nuclear Overhauser effects (NOEs), dispersion of the chemical shifts, amide proton chemical shift temperature coefficients, amide proton exchange rates, and (15)N[(1)H]-NOEs show that OmpX in 8 M urea at pH 6.5 is globally unfolded, but adopts local nonrandom conformations in the polypeptide segments of residues 73-82 and 137-145. For these two regions, numerous medium-range and longer-range NOEs were observed, which were used as the input for structure calculations of these polypeptide segments with the program DYANA. The segment 73-82 forms a quite regular helical structure, with only loosely constrained amino acid side chains. In the segment 137-145, the tryptophan residue 140 forms the core of a small hydrophobic cluster. Both nonrandom structures are present with an abundance of about 25% of the protein molecules. The sequence-specific NMR assignment and the physicochemical characterization of urea-denatured OmpX presented in this paper are currently used as a platform for investigations of the folding mechanism of this integral membrane protein. |
| Links |
PubMed Online version:10.1021/bi0356606 |
| Keywords |
Amino Acid Sequence; Bacterial Outer Membrane Proteins/chemistry; Computer Simulation; Escherichia coli Proteins/chemistry; Hydrolases; Models, Molecular; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Protein Conformation; Protein Denaturation; Protein Folding; Solutions; Thermodynamics; Urea/chemistry |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.