[4] Protein folding in membranes: Determining energetics of peptide-bilayer interactions

White, Stephen H.; Wimley, William C.; Ladokhin, Alexey S.; Hristova, Kalina

doi:10.1016/s0076-6879(98)95035-2

Cited by 269 publications

(327 citation statements)

References 63 publications

Supporting

Mentioning

319

Contrasting

Order By: Relevance

“…To determine the affinity of Nogo-66 for lipid, we titrated DMPC vesicles into a solution of Nogo-66 and monitored ellipticity at 222 nm. Nogo-66 binds DMPC with a moderate partition coefficient (18), K x ¼ 1.8 × 10 5 . Thus, Nogo-66 interacts relatively strongly with lipid even in the absence of TM helices.…”

Section: Resultsmentioning

confidence: 99%

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Vasudevan

Schulz²,

Zhou³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Repair of damage to the central nervous system (CNS) is inhibited by the presence of myelin proteins that prevent axonal regrowth. Consequently, growth inhibitors and their common receptor have been identified as targets in the treatment of injury to the CNS. Here we describe the structure of the extracellular domain of the neurite outgrowth inhibitor (Nogo) in a membrane-like environment. Isoforms of Nogo are expressed with a common C terminus containing two transmembrane (TM) helices. The ectodomain between the two TM helices, Nogo-66, is active in preventing axonal growth [GrandPre T, Nakamura F, Vartanian T, Strittmatter SM (2000) Nature 403:439-444]. We studied the structure of Nogo-66 alone and in the presence of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) vesicles and dodecylphosphocholine (DPC) micelles as membrane mimetics. We find that Nogo-66 is largely disordered when free in solution. However, when bound to a phosphocholine surface Nogo-66 adopts a unique, stable fold, even in the absence of TM anchors. Using paramagnetic probes and protein-DPC nuclear Overhauser effects (NOEs), we define portions of the growth inhibitor likely to be accessible on the cell surface. With these data we predict that residues (28-58) are available to bind the Nogo receptor, which is entirely consistent with functional assays. Moreover, the conformations and relative positions of side chains recognized by the receptor are now defined and provide a foundation for antagonist design.peripheral | lipid surface | CNS | membrane protein | nmr

show abstract

Section: Resultsmentioning

confidence: 99%

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Vasudevan

Schulz²,

Zhou³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…CD spectral changes are frequently observed when disordered peptides in solution partition into lipid bilayers (54). The high cost of partitioning peptide bonds into the membrane interface is a major driving force for secondary structure formation in membrane environments (23,55,56).…”

Section: Discussionmentioning

confidence: 99%

Length Effects in Antimicrobial Peptides of the (RW)_nSeries

Liu

Brady

Young

et al. 2007

Antimicrob Agents Chemother

178

136

View full text Add to dashboard Cite

“…Bilayer interaction of tryptophan-containing peptides often results in strong changes in intrinsic fluorescence, which, after appropriate corrections (1), can be used to determine the ΔG of bilayer partitioning using equilibrium titration (8). Surprisingly, we found that the addition of extruded large unilamellar vesicles (LUV) to GsMTx4 leads to marginal changes in tryptophan's emission (Fig.…”

Section: Introductionmentioning

confidence: 95%

“…We chose melittin to test the validity of our new titration protocol because its fluorescence changes markedly upon membrane interaction and its membrane-binding properties have been studied extensively by various methods (1,8,9). The results of melittin titration with POPC LUV in two buffer systems, containing 50 mM of KCl or KI, are presented in Fig.…”

Section: Nih Public Accessmentioning

confidence: 99%

“…As expected, the increase in fluorescence intensity upon membrane partitioning is higher in the presence of KI, due to higher iodide quenching of an aqueous melittin as compared to a membrane-bound one (10,11). Fluorescence intensities I, corrected for scattering and dilution, were fitted to (1): (8). The free energies of transfer from water to membrane were calculated from the mole-fraction partition coefficients using (2) For melittin, a peptide with already pronounced increase in fluorescence upon bilayer partitioning even in the absence of aqueous quenchers, the addition of iodide still increased the spectroscopic response to membrane binding (I max -1) almost three-fold.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Quenching-enhanced fluorescence titration protocol for accurate determination of free energy of membrane binding

Posokhov

Gottlieb

Ladokhin

2007

Analytical Biochemistry

Self Cite

View full text Add to dashboard Cite

Fluorescence spectroscopy is a convenient tool to examine peptide-membrane interactions at equilibrium (1) owing to the change in emission properties of many fluorophores (including tryptophan) during transfer from an aqueous environment into a lipid bilayer. In some cases (e.g. mechanosensitive channel blocker GsMTx4 described here), however, binding-associated emission changes are too small for reliable determination of the free energy of partitioning, ΔG. To enhance the spectroscopic response to binding we implemented the titration with lipid vesicles in the presence of aqueous ionic quencher iodide, which preferentially quenchers fluorescence of the free peptide in solution. We have verified the accuracy of this new titration protocol using the well-studied peptide melittin. Keywordstryptophan; fluorescence quenching; lipid bilayer; ion channels; iodide; membrane partitioningThe mechanosensitive channel blocker GsMTx4 (2), along with a number of other gating modifiers (e.g., VsTx1, hanatoxin, SGTx), belongs to a cysteine-knot family of peptides. These peptides, stabilized by three disulfide bridges, possess a hydrophobic and a hydrophilic face and interact with lipid bilayers, which may be essential for their physiological activity (2-5). We need to understand the thermodynamic and structural properties of these interactions, but progress has been hampered by our inability to measure the small spectroscopic changes associated with membrane binding of peptides like GsMTx4.The hydrophobic face of GsMTx4 is dominated by two tryptophan residues (6), which are expected to contribute strongly and favorably to the free energy of bilayer partitioning, ΔG (7). Bilayer interaction of tryptophan-containing peptides often results in strong changes in intrinsic fluorescence, which, after appropriate corrections (1), can be used to determine the ΔG of bilayer partitioning using equilibrium titration (8). Surprisingly, we found that the addition of extruded large unilamellar vesicles (LUV) to GsMTx4 leads to marginal changes in tryptophan's emission (Fig. 1A), which normally is associated with lack membrane *To whom correspondence should be addressed: Phone: 913-588-0489 FAX: 913-588-7440 Email: aladokhin@kumc.edu. † This research was supported by NIH grant GM-069783 (A.S.L.). P.A.G. was supported by NIH HL-054887 and the Oshei Foundation grants to Frederick Sachs.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. In contrast, we found a pronounced reduction in quenching by aqueous ions in the presence of LUV, indicating shielding of the tryptophan's by the lipid bilayer. For e...

show abstract

[4] Protein folding in membranes: Determining energetics of peptide-bilayer interactions

Cited by 269 publications

References 63 publications

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Length Effects in Antimicrobial Peptides of the (RW)_nSeries

Quenching-enhanced fluorescence titration protocol for accurate determination of free energy of membrane binding

Contact Info

Product

Resources

About

[4] Protein folding in membranes: Determining energetics of peptide-bilayer interactions

Cited by 269 publications

References 63 publications

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Protein folding at the membrane interface, the structure of Nogo-66 requires interactions with a phosphocholine surface

Length Effects in Antimicrobial Peptides of the (RW)nSeries

Quenching-enhanced fluorescence titration protocol for accurate determination of free energy of membrane binding

Contact Info

Product

Resources

About

Length Effects in Antimicrobial Peptides of the (RW)_nSeries