Site-selective biomineralization of native biological membranes

2014 ◽  
Vol 2 (40) ◽  
pp. 6924-6930 ◽  
Author(s):  
Annegret P. Busch ◽  
Daniel Rhinow ◽  
Fang Yang ◽  
Hendrik Reinhardt ◽  
André Beyer ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Biological Membrane ◽  
Biological Membranes ◽  
Integral Membrane Proteins ◽  
Genetical Modification ◽  
Site Selective

Genetical modification of integral membrane proteins with poly-arginine sequences enables site-selective silicification of a native biological membrane.

scholarly journals Selection of Biophysical Methods for Characterisation of Membrane Proteins

2019 ◽  
Vol 20 (10) ◽  
pp. 2605 ◽  
Author(s):  
Tristan O. C. Kwan ◽  
Rosana Reis ◽  
Giuliano Siligardi ◽  
Rohanah Hussain ◽  
Harish Cheruvara ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Early Stage ◽  
Biological Membrane ◽  
Basic Research ◽  
Integral Membrane Protein ◽  
Integral Membrane Proteins ◽  
Functional Protein ◽  
Protein Research ◽  
Selection Of

Over the years, there have been many developments and advances in the field of integral membrane protein research. As important pharmaceutical targets, it is paramount to understand the mechanisms of action that govern their structure–function relationships. However, the study of integral membrane proteins is still incredibly challenging, mostly due to their low expression and instability once extracted from the native biological membrane. Nevertheless, milligrams of pure, stable, and functional protein are always required for biochemical and structural studies. Many modern biophysical tools are available today that provide critical information regarding to the characterisation and behaviour of integral membrane proteins in solution. These biophysical approaches play an important role in both basic research and in early-stage drug discovery processes. In this review, it is not our objective to present a comprehensive list of all existing biophysical methods, but a selection of the most useful and easily applied to basic integral membrane protein research.

scholarly journals The energetics of protein–lipid interactions as viewed by molecular simulations

2019 ◽  
Vol 48 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Robin A. Corey ◽  
Phillip J. Stansfeld ◽  
Mark S.P. Sansom
Keyword(s):  
Membrane Proteins ◽  
Biological Membrane ◽  
Lipid Binding ◽  
Integral Membrane Proteins ◽  
Free Energies ◽  
Computational Approaches ◽  
Lipid Interactions ◽  
Current State ◽  
Peripheral Membrane Proteins ◽  
Lipid Species

Membranes are formed from a bilayer containing diverse lipid species with which membrane proteins interact. Integral, membrane proteins are embedded in this bilayer, where they interact with lipids from their surroundings, whilst peripheral membrane proteins bind to lipids at the surface of membranes. Lipid interactions can influence the function of membrane proteins, either directly or allosterically. Both experimental (structural) and computational approaches can reveal lipid binding sites on membrane proteins. It is, therefore, important to understand the free energies of these interactions. This affords a more complete view of the engagement of a particular protein with the biological membrane surrounding it. Here, we describe many computational approaches currently in use for this purpose, including recent advances using both free energy and unbiased simulation methods. In particular, we focus on interactions of integral membrane proteins with cholesterol, and with anionic lipids such as phosphatidylinositol 4,5-bis-phosphate and cardiolipin. Peripheral membrane proteins are exemplified via interactions of PH domains with phosphoinositide-containing membranes. We summarise the current state of the field and provide an outlook on likely future directions of investigation.

Molecular cytochemistry of freeze-fractured cells

1986 ◽  
Vol 44 ◽  
pp. 894-897
Author(s):  
Pedro Pinto da Silva
Keyword(s):  
Membrane Proteins ◽  
Membrane Surface ◽  
Freeze Fracture ◽  
Biological Membranes ◽  
Bilayer Membrane ◽  
Integral Membrane Proteins ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
Freeze Etching

I will describe four approaches that combine cytochemistry with freeze-fracture: 1) FREEZE-ETCHING; 2) FRACTURE-LABEL; 3) FRACTURE-PERMEATION; and 4) LABEL-FRACTURE. These techniques, in particular fracture-label, involve delicate points of interpretation and numerous validating controls. In the publications listed at the end, these issues have been addressed in detail.1. FREEZE-ETCHING. I developed freeze-etching as a cytochemical approach to prove that membranes were split by freeze-fracture and to show that biological membranes were comprised of a bilayer membrane continuum interrupted by integral membrane proteins.1 - 4 In freeze-etching, the distribution of the marker over the membrane surface exposed by sublimation is compared to that of the intramembrane particles exposed by fracture. It is often required to aggregate the particles into domains larger than the labeling molecules (Fig. 1). This, and the need for freezing in distilled water, severely limits the application of freeze-etching.

scholarly journals Reversible penetration of α-glutathione S-transferase into biological membranes revealed by photosensitized labelling in situ

1998 ◽  
Vol 335 (3) ◽  
pp. 597-604 ◽  
Author(s):  
Natasha MEREZHINSKAYA ◽  
Gemma A. J. KUIJPERS ◽  
Yossef RAVIV
Keyword(s):  
Influenza Virus ◽  
Membrane Proteins ◽  
Lipid Bilayer ◽  
Biological Membranes ◽  
Membrane Lipid ◽  
Integral Membrane Proteins ◽  
Glutathione S Transferase ◽  
Membrane Lipid Bilayer ◽  
Influenza Virus Haemagglutinin ◽  
Virus Haemagglutinin

Fluorescent lipid analogue 3,3´-dioctadecyloxacarbocyanine incorporated into biological membranes was used to induce photoactivation of a hydrophobic probe 5-[125I]iodonaphthyl-1-azide (125INA) by energy transfer and to thereby confine subsequent radiolabelling of proteins to the lipid bilayer. This approach was applied in bovine chromaffin cells to discover cytosolic proteins that reversibly penetrate into membrane domains. α-Glutathione S-transferase (α-GST) was identified as the only labelled protein in bovine chromaffin-cell cytosol, indicating that it inserts reversibly into the membrane lipid bilayer. The selectivity of the labelling towards the lipid bilayer is demonstrated by showing that influenza virus haemagglutinin becomes labelled by 125INA only after the insertion of this protein into the target membrane. The molar 125INA:protein ratio was used as a quantitative criterion for evaluation of the penetration of proteins into the membrane lipid bilayer. This ratio was calculated for four integral membrane proteins and four soluble proteins that interact with biological membranes. The values for four integral membrane proteins (erythrocyte anion transporter, multidrug transporter gp-170, dopamine transporter and fusion-competent influenza virus haemagglutinin) were 1, 8, 2 and 2, respectively, whereas for soluble proteins (annexin VII, protein kinase C, BSA and influenza virus haemagglutinin) the values were 0.002, 0, 0.002 and 0.02, respectively. The molar ratio for α-GST was found to be 1, compatible with the values obtained for integral membrane proteins.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

How Do Lipids Affect the Structure and Function of Integral Membrane Proteins

2012 ◽  
Vol 28 (11) ◽  
pp. 866
Author(s):  
Jie HENG ◽  
Yan WU ◽  
Xianping WANG ◽  
Kai ZHANG
Keyword(s):  
Membrane Proteins ◽  
Structure And Function ◽  
Integral Membrane Proteins ◽  
And Function
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