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Title: Atomic-level description of protein–lipid interactions using an accelerated membrane model

Authors:
; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1367694
Resource Type:
Journal Article: Published Article
Journal Name:
Biochimica et Biophysica Acta. Biomembranes
Additional Journal Information:
Journal Volume: 1858; Journal Issue: 7 PB; Related Information: CHORUS Timestamp: 2017-10-06 21:48:03; Journal ID: ISSN 0005-2736
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Baylon, Javier L., Vermaas, Josh V., Muller, Melanie P., Arcario, Mark J., Pogorelov, Taras V., and Tajkhorshid, Emad. Atomic-level description of protein–lipid interactions using an accelerated membrane model. Netherlands: N. p., 2016. Web. doi:10.1016/j.bbamem.2016.02.027.
Baylon, Javier L., Vermaas, Josh V., Muller, Melanie P., Arcario, Mark J., Pogorelov, Taras V., & Tajkhorshid, Emad. Atomic-level description of protein–lipid interactions using an accelerated membrane model. Netherlands. doi:10.1016/j.bbamem.2016.02.027.
Baylon, Javier L., Vermaas, Josh V., Muller, Melanie P., Arcario, Mark J., Pogorelov, Taras V., and Tajkhorshid, Emad. 2016. "Atomic-level description of protein–lipid interactions using an accelerated membrane model". Netherlands. doi:10.1016/j.bbamem.2016.02.027.
@article{osti_1367694,
title = {Atomic-level description of protein–lipid interactions using an accelerated membrane model},
author = {Baylon, Javier L. and Vermaas, Josh V. and Muller, Melanie P. and Arcario, Mark J. and Pogorelov, Taras V. and Tajkhorshid, Emad},
abstractNote = {},
doi = {10.1016/j.bbamem.2016.02.027},
journal = {Biochimica et Biophysica Acta. Biomembranes},
number = 7 PB,
volume = 1858,
place = {Netherlands},
year = 2016,
month = 7
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.bbamem.2016.02.027

Citation Metrics:
Cited by: 7works
Citation information provided by
Web of Science

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  • Spinach plastocyanin binds to both electrically neutral and positively charged lipid bilayer vesicles whereas cytochrome c only binds electrostatically to negatively charged vesicles. Laser flash photolysis using lumiflavin semiquinone as a reductant demonstrates that the reactivity of plastocyanin is increased as much as 6-fold when it is membrane bound whereas the rate constant for cytochrome c reduction is decreased by approximately a factor of 3. Membrane-bound plastocyanin reduction occurs via a two-step mechanism, probably involving prior association of lumiflavin semiquinone with the bilayer. In contrast, cytochrome c reduction in the membrane-bound state follows simple second-order kinetics, implying that the redoxmore » site in the bound state is still accessible to lumiflavin semiquinone in solution, although the rate constant is decreased by approximately 3-fold. These results are interpreted as indicating that the bilayer-protein interaction with plastocyanin leads to a steric blockage of the electron-transfer site from the aqueous phase. Little or no hindrance of the redox site occurs with cytochrome c, suggesting a high degree of mobility of this protein on the bilayer surface. Although the increase in plastocyanin reactivity upon binding to the bilayer is quite interesting, its cause remains unclear and requires further study. The results illustrate the utility of laser flash photolysis as a probe of membrane-protein interactions.« less
  • Very little information is available in the literature concerning the experimental heavy-atom phasing of membrane-protein structures where the crystals have been grown using the lipid cubic phase (in meso) method. In this paper, pre-labelling, co-crystallization, soaking, site-specific mercury binding to genetically engineered single-cysteine mutants and selenomethionine labelling as applied to an integral membrane kinase crystallized in meso are described. An assay to assess cysteine accessibility for mercury labelling of membrane proteins is introduced. Despite the marked increase in the number of membrane-protein structures solved using crystals grown by the lipid cubic phase or in meso method, only ten have beenmore » determined by SAD/MAD. This is likely to be a consequence of the technical difficulties associated with handling proteins and crystals in the sticky and viscous hosting mesophase that is usually incubated in glass sandwich plates for the purposes of crystallization. Here, a four-year campaign aimed at phasing the in meso structure of the integral membrane diacylglycerol kinase (DgkA) from Escherichia coli is reported. Heavy-atom labelling of this small hydrophobic enzyme was attempted by pre-labelling, co-crystallization, soaking, site-specific mercury binding to genetically engineered single-cysteine mutants and selenomethionine incorporation. Strategies and techniques for special handling are reported, as well as the typical results and the lessons learned for each of these approaches. In addition, an assay to assess the accessibility of cysteine residues in membrane proteins for mercury labelling is introduced. The various techniques and strategies described will provide a valuable reference for future experimental phasing of membrane proteins where crystals are grown by the lipid cubic phase method.« less
  • A comparison of X-ray diffraction and radiographic techniques for the location and characterization of protein crystals is demonstrated on membrane protein crystals mounted within lipid cubic phase material. The focus in macromolecular crystallography is moving towards even more challenging target proteins that often crystallize on much smaller scales and are frequently mounted in opaque or highly refractive materials. It is therefore essential that X-ray beamline technology develops in parallel to accommodate such difficult samples. In this paper, the use of X-ray microradiography and microtomography is reported as a tool for crystal visualization, location and characterization on the macromolecular crystallography beamlinesmore » at the Diamond Light Source. The technique is particularly useful for microcrystals and for crystals mounted in opaque materials such as lipid cubic phase. X-ray diffraction raster scanning can be used in combination with radiography to allow informed decision-making at the beamline prior to diffraction data collection. It is demonstrated that the X-ray dose required for a full tomography measurement is similar to that for a diffraction grid-scan, but for sample location and shape estimation alone just a few radiographic projections may be required.« less