Methods to study membrane protein structure in solution.

G D Henry; B D Sykes

doi:10.1016/s0076-6879(94)39020-7

Home/Archive/PubMed

PubMed · 7830597

Methods to study membrane protein structure in solution.

G D Henry·B D Sykes

View original source ↗Export metadata ↓

Abstract

Membrane protein structure is difficult to determine by any technique. NMR spectroscopy of membrane proteins in solution can proceed using methods identical to those that have been successfully applied to numerous water-soluble proteins providing suitable solubilization conditions can be found. Organic solvents and small detergent micelles have correlation times short enough for structure determination based on 1H NOEs. Although it is difficult to generalize as each system is unique, organic solvents and micelles of strong detergents such as SDS are useful for amphiphilic peptides and small membrane proteins, whereas larger proteins need milder treatment to preserve the tertiary structure. Small unilamellar phospholipid vesicles are much too large for NOE-based structure determination, but they still fall under the domain of solution-state NMR and can be useful in certain circumstances.

Explore related subjects

Amides Detergents Endopeptidases Hydrogen Liposomes Magnetic Resonance Spectroscopy Membrane Proteins Molecular Probes Molecular Structure Peptides Solutions Solvents Journal Article Research Support, Non-U.S. Gov't Review

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

G D Henry, B D Sykes. 1994. Methods to study membrane protein structure in solution.. https://doi.org/10.1016/s0076-6879(94)39020-7

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1996

Synthesis of glycolipids containing disaccharides and two longer alkyl chains and their applications as enzyme modifiers.

The aminolysis between p-(aminomethyl)benzoic acid and lactobiono-1,5-lactone was carried out in Me2SO in quantitative yield. The amide formed thus was used directly for the final reaction without isolation of the intermediate from the reaction mixture. This simple one-pot procedure finished a convenient and useful synthesis of the target N-[p-(dialkyl-L-glutamatecarbonyl)-benzyl]lactobionamides. The phase-transition temperature of glycolipids was shown to greatly depend on the structure between the hydrophilic moiety and the hydrophobic segment of the glycolipids. The yield of proteins of lipases coated with the glycolipids containing disaccharides remarkably increased with alkyl-chain length, which was higher than that with glycolipids containing monosaccharides. The yields were also closely correlated to the origin of the lipases. The enzymatic reactivity of lipid-coated lipase PS was seldom affected by the hydrophobic segment of lipids, but its enantioselectivity was mainly affected by the hydrophilic moiety of lipids.

Amides↗

PubMed1996

Direct evidence for modified solvent structure within the hydration shell of a hydrophobic amino acid.

Neutron scattering experiments are used to determine scattering profiles for aqueous solutions of hydrophobic and hydrophilic amino acid analogs. Solutions of hydrophobic solutes show a shift in the main diffraction peak to smaller angle as compared with pure water, whereas solutions of hydrophilic solutes do not. The same difference for solutions of hydrophobic and hydrophilic side chains is also predicted by molecular dynamics simulations. The neutron scattering curves of aqueous solutions of hydrophobic amino acids at room temperature are qualitatively similar to differences between the liquid molecular structure functions measured for ambient and supercooled water. The nonpolar solute-induced expansion of water structure reported here is also complementary to recent neutron experiments where compression of aqueous solvent structure has been observed at high salt concentration.

Amides↗

PubMed1996

Hydrogen/deuterium exchange kinetics of apolipophorin-III in lipid-free and phospholipid-bound states. An analysis by Fourier transform infrared spectroscopy.

Attenuated total reflection Fourier transform infrared spectroscopy was used to probe the kinetics of hydrogen/deuterium exchange in Manduca sexta apolipophorin-III (apoLp-III). ApoLp-III is an exchangeable apolipoprotein that is made up of five elongated amphipathic alpha-helices in a helical bundle conformation in the monomeric lipid-free form. Upon interaction with phospholipids, it is postulated to undergo a large conformational change whereby the hydrophobic interior is exposed, facilitating binding to the lipid surfaces. We have used the lipid-free and dimyristoylphosphatidylcholine-bound apoLp-III to study the dynamically variable domains in the two forms. Three populations of amide protons varying in their hydrogen/deuterium exchange rates were found to exist: slow, intermediate, and fast exchanging, which could correspond to completely buried, partially buried, and solvent-exposed domains on the protein in both the states. In lipid-free apoLp-III, 36, 12, and 52% of the total residues contributed to the slow, intermediate, and fast exchanging populations, respectively. In the dimyristoylphosphatidylcholine-bound form, the corresponding distribution was 20, 16, and 64%, representing a 12% increase in the number of exposed residues. The results are discussed in terms of increased solvent accessibility due to gross tertiary structural reorganization.

Amides↗