2L0L: DsbB2 peptide structure in 70% TFE

The two-stage model for membrane protein folding postulates that individual helices form first and are subsequently packed against each other. To probe the two-stage model, the structures of peptides representing individual transmembrane helices of the disulfide bond forming protein B have been studied in trifluoroethanol solution as well as in detergent micelles using nuclear magnetic resonance (NMR) and circular dichroism spectroscopy. In TFE solution, peptides showed well-defined alpha-helical structures. Peptide structures in TFE were compared to the structures of full-length protein obtained by X-ray crystallography and NMR. The extent of alpha-helical secondary structure coincided well, lending support for the two-stage model for membrane protein folding. However, the conformation of some amino acid side chains differs between the structures of peptide and full-length protein. In micellar solution, the peptides also adopted a helical structure, albeit of reduced definition. Using measurements of paramagnetic relaxation enhancement, peptides were confirmed to be embedded in micelles. These observations may indicate that in the native protein, tertiary interactions additionally stabilize the secondary structure of the individual transmembrane helices.
PDB ID: 2L0LDownload
MMDB ID: 89010
PDB Deposition Date: 2010/7/8
Updated in MMDB: 2018/05
Experimental Method:
solution nmr
Similar Structures:
Biological Unit for 2L0L: monomeric; determined by author
Molecular Components in 2L0L
Label Count Molecule
Protein (1 molecule)
Oxidoreductase That Catalyzes Reoxidation of Dsba Protein Disulfide Isomerase I
Molecule annotation
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Citing MMDB