scholarly journals Structural cavities are critical to balancing stability and activity of a membrane-integral enzyme

2020 ◽  
Vol 117 (36) ◽  
pp. 22146-22156
Author(s):  
Ruiqiong Guo ◽  
Zixuan Cang ◽  
Jiaqi Yao ◽  
Miyeon Kim ◽  
Erin Deans ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Weak Interactions ◽  
Protein Structures ◽  
Dynamics Simulation ◽  
Energetic Cost ◽  
Functional Movement ◽  
Packing Defects ◽  
The Stability ◽  
And Function

Packing interaction is a critical driving force in the folding of helical membrane proteins. Despite the importance, packing defects (i.e., cavities including voids, pockets, and pores) are prevalent in membrane-integral enzymes, channels, transporters, and receptors, playing essential roles in function. Then, a question arises regarding how the two competing requirements, packing for stability vs. cavities for function, are reconciled in membrane protein structures. Here, using the intramembrane protease GlpG ofEscherichiacolias a model and cavity-filling mutation as a probe, we tested the impacts of native cavities on the thermodynamic stability and function of a membrane protein. We find several stabilizing mutations which induce substantial activity reduction without distorting the active site. Notably, these mutations are all mapped onto the regions of conformational flexibility and functional importance, indicating that the cavities facilitate functional movement of GlpG while compromising the stability. Experiment and molecular dynamics simulation suggest that the stabilization is induced by the coupling between enhanced protein packing and weakly unfavorable lipid desolvation, or solely by favorable lipid solvation on the cavities. Our result suggests that, stabilized by the relatively weak interactions with lipids, cavities are accommodated in membrane proteins without severe energetic cost, which, in turn, serve as a platform to fine-tune the balance between stability and flexibility for optimal activity.

scholarly journals BRANEart: identify stability strength and weakness regions in membrane proteins

2021 ◽  
Author(s):  
Sankar Basu ◽  
Simon S. Assaf ◽  
Fabian Teheux ◽  
Marianne Rooman ◽  
Fabrizio Pucci
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Conformational Changes ◽  
Large Scale ◽  
Protein Structures ◽  
Accurate Method ◽  
Globular Proteins ◽  
Stability Properties ◽  
Overall Stability ◽  
The Stability

AbstractUnderstanding the role of stability strengths and weaknesses in proteins is a key objective for rationalizing their dynamical and functional properties such as conformational changes, catalytic activity, and protein-protein and protein-ligand interactions. We present BRANEart, a new, fast and accurate method to evaluate the per-residue contributions to the overall stability of membrane proteins. It is based on an extended set of recently introduced statistical potentials derived from membrane protein structures, which better describe the stability properties of this class of proteins than standard potentials derived from globular proteins. We defined a per-residue membrane propensity index from combinations of these potentials, which can be used to identify residues which strongly contribute to the stability of the transmembrane region or which would, on the contrary, be more stable in extramembrane regions, or vice versa. Large-scale application to membrane and globular proteins sets and application to tests cases show excellent agreement with experimental data. BRANEart thus appears as a useful instrument to analyze in detail the overall stability properties of a target membrane protein, to position it relative to the lipid bilayer, and to rationally modify its biophysical characteristics and function. BRANEart can be freely accessed from http://babylone.3bio.ulb.ac.be/BRANEart.

scholarly journals BRANEart: Identify Stability Strength and Weakness Regions in Membrane Proteins

2021 ◽  
Vol 1 ◽  
Author(s):  
Sankar Basu ◽  
Simon S. Assaf ◽  
Fabian Teheux ◽  
Marianne Rooman ◽  
Fabrizio Pucci
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Conformational Changes ◽  
Large Scale ◽  
Protein Structures ◽  
Accurate Method ◽  
Globular Proteins ◽  
Stability Properties ◽  
Overall Stability ◽  
The Stability

Understanding the role of stability strengths and weaknesses in proteins is a key objective for rationalizing their dynamical and functional properties such as conformational changes, catalytic activity, and protein-protein and protein-ligand interactions. We present BRANEart, a new, fast and accurate method to evaluate the per-residue contributions to the overall stability of membrane proteins. It is based on an extended set of recently introduced statistical potentials derived from membrane protein structures, which better describe the stability properties of this class of proteins than standard potentials derived from globular proteins. We defined a per-residue membrane propensity index from combinations of these potentials, which can be used to identify residues which strongly contribute to the stability of the transmembrane region or which would, on the contrary, be more stable in extramembrane regions, or vice versa. Large-scale application to membrane and globular proteins sets and application to tests cases show excellent agreement with experimental data. BRANEart thus appears as a useful instrument to analyze in detail the overall stability properties of a target membrane protein, to position it relative to the lipid bilayer, and to rationally modify its biophysical characteristics and function. BRANEart can be freely accessed from http://babylone.3bio.ulb.ac.be/BRANEart.

Nanoscale lipid membrane mimetics in spin-labeling and electron paramagnetic resonance spectroscopy studies of protein structure and function

2017 ◽  
Vol 6 (1) ◽  
pp. 75-92 ◽  
Author(s):  
Elka R. Georgieva
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Protein Structure ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Spin Labeling ◽  
Structure And Function ◽  
Protein Structure And Function ◽  
Paramagnetic Resonance ◽  
And Function ◽  
Electron Paramagnetic

AbstractCellular membranes and associated proteins play critical physiological roles in organisms from all life kingdoms. In many cases, malfunction of biological membranes triggered by changes in the lipid bilayer properties or membrane protein functional abnormalities lead to severe diseases. To understand in detail the processes that govern the life of cells and to control diseases, one of the major tasks in biological sciences is to learn how the membrane proteins function. To do so, a variety of biochemical and biophysical approaches have been used in molecular studies of membrane protein structure and function on the nanoscale. This review focuses on electron paramagnetic resonance with site-directed nitroxide spin-labeling (SDSL EPR), which is a rapidly expanding and powerful technique reporting on the local protein/spin-label dynamics and on large functionally important structural rearrangements. On the other hand, adequate to nanoscale study membrane mimetics have been developed and used in conjunction with SDSL EPR. Primarily, these mimetics include various liposomes, bicelles, and nanodiscs. This review provides a basic description of the EPR methods, continuous-wave and pulse, applied to spin-labeled proteins, and highlights several representative applications of EPR to liposome-, bicelle-, or nanodisc-reconstituted membrane proteins.

Mutations in transmembrane proteins: diseases, evolutionary insights, prediction and comparison with globular proteins

2020 ◽  
Author(s):  
Jan Zaucha ◽  
Michael Heinzinger ◽  
A Kulandaisamy ◽  
Evans Kataka ◽  
Óscar Llorian Salvádor ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Lipid Bilayers ◽  
Protein Structures ◽  
Experimental Studies ◽  
Single Amino Acid ◽  
Evolutionary Information ◽  
Missense Variants ◽  
Current State ◽  
Aqueous Environments

Abstract Membrane proteins are unique in that they interact with lipid bilayers, making them indispensable for transporting molecules and relaying signals between and across cells. Due to the significance of the protein’s functions, mutations often have profound effects on the fitness of the host. This is apparent both from experimental studies, which implicated numerous missense variants in diseases, as well as from evolutionary signals that allow elucidating the physicochemical constraints that intermembrane and aqueous environments bring. In this review, we report on the current state of knowledge acquired on missense variants (referred to as to single amino acid variants) affecting membrane proteins as well as the insights that can be extrapolated from data already available. This includes an overview of the annotations for membrane protein variants that have been collated within databases dedicated to the topic, bioinformatics approaches that leverage evolutionary information in order to shed light on previously uncharacterized membrane protein structures or interaction interfaces, tools for predicting the effects of mutations tailored specifically towards the characteristics of membrane proteins as well as two clinically relevant case studies explaining the implications of mutated membrane proteins in cancer and cardiomyopathy.

scholarly journals Plasma Membrane Protein Nce102 Modulates Morphology and Function of the Yeast Vacuole

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1476
Author(s):  
Katarina Vaskovicova ◽  
Petra Vesela ◽  
Jakub Zahumensky ◽  
Dagmar Folkova ◽  
Maria Balazova ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Vacuolar Membrane ◽  
Yeast Culture ◽  
Membrane Domains ◽  
Biological Functions ◽  
Plasma Membrane Protein ◽  
Cell Architecture ◽  
And Function

Membrane proteins are targeted not only to specific membranes in the cell architecture, but also to distinct lateral microdomains within individual membranes to properly execute their biological functions. Yeast tetraspan protein Nce102 has been shown to migrate between such microdomains within the plasma membrane in response to an acute drop in sphingolipid levels. Combining microscopy and biochemistry methods, we show that upon gradual ageing of a yeast culture, when sphingolipid demand increases, Nce102 migrates from the plasma membrane to the vacuole. Instead of being targeted for degradation it localizes to V-ATPase-poor, i.e., ergosterol-enriched, domains of the vacuolar membrane, analogous to its plasma membrane localization. We discovered that, together with its homologue Fhn1, Nce102 modulates vacuolar morphology, dynamics, and physiology. Specifically, the fusing of vacuoles, accompanying a switch of fermenting yeast culture to respiration, is retarded in the strain missing both proteins. Furthermore, the absence of either causes an enlargement of ergosterol-rich vacuolar membrane domains, while the vacuoles themselves become smaller. Our results clearly show decreased stability of the V-ATPase in the absence of either Nce102 or Fhn1, a possible result of the disruption of normal microdomain morphology of the vacuolar membrane. Therefore, the functionality of the vacuole as a whole might be compromised in these cells.

scholarly journals Structures of membrane proteins

2010 ◽  
Vol 43 (1) ◽  
pp. 65-158 ◽  
Author(s):  
Kutti R. Vinothkumar ◽  
Richard Henderson
Keyword(s):  
Protein Structure ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Structures ◽  
Protein Structure Determination ◽  
Membrane Protein Structure ◽  
Expression Systems ◽  
Genome Sequences ◽  
Conformational Variability ◽  
Efficient Expression

AbstractIn reviewing the structures of membrane proteins determined up to the end of 2009, we present in words and pictures the most informative examples from each family. We group the structures together according to their function and architecture to provide an overview of the major principles and variations on the most common themes. The first structures, determined 20 years ago, were those of naturally abundant proteins with limited conformational variability, and each membrane protein structure determined was a major landmark. With the advent of complete genome sequences and efficient expression systems, there has been an explosion in the rate of membrane protein structure determination, with many classes represented. New structures are published every month and more than 150 unique membrane protein structures have been determined. This review analyses the reasons for this success, discusses the challenges that still lie ahead, and presents a concise summary of the key achievements with illustrated examples selected from each class.

scholarly journals Stress-Responsive Systems Set Specific Limits to the Overproduction of Membrane Proteins in Bacillus subtilis

2009 ◽  
Vol 75 (23) ◽  
pp. 7356-7364 ◽  
Author(s):  
Jessica C. Zweers ◽  
Thomas Wiegert ◽  
Jan Maarten van Dijl
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Drug Targets ◽  
Protein Production ◽  
Cell Envelope ◽  
Regulatory System ◽  
Interesting Candidate ◽  
High Level ◽  
And Function

ABSTRACT Essential membrane proteins are generally recognized as relevant potential drug targets due to their exposed localization in the cell envelope. Unfortunately, high-level production of membrane proteins for functional and structural analyses is often problematic. This is mainly due to their high overall hydrophobicity. To develop new concepts for membrane protein overproduction, we investigated whether the biogenesis of overproduced membrane proteins is affected by stress response-related proteolytic systems in the membrane. For this purpose, the well-established expression host Bacillus subtilis was used to overproduce eight essential membrane proteins from B. subtilis and Staphylococcus aureus. The results show that the σW regulon (responding to cell envelope perturbations) and the CssRS two-component regulatory system (responding to unfolded exported proteins) set critical limits to membrane protein production in large quantities. The identified sigW or cssRS mutant B. subtilis strains with significantly improved capacity for membrane protein production are interesting candidate expression hosts for fundamental research and biotechnological applications. Importantly, our results pinpoint the interdependent expression and function of membrane-associated proteases as key parameters in bacterial membrane protein production.

scholarly journals The Role of Packing Defects in the Stability and Function of the Intramembrane Protease GlpG

2017 ◽  
Vol 112 (3) ◽  
pp. 86a
Author(s):  
Ruiqiong Guo ◽  
Zixuan Cang ◽  
Deans Erin ◽  
Guowei Wei ◽  
Heedeok Hong
Keyword(s):  
Packing Defects ◽  
The Stability ◽  
And Function

scholarly journals Mass spectrometry of membrane protein complexes

2019 ◽  
Vol 400 (7) ◽  
pp. 813-829 ◽  
Author(s):  
Julian Bender ◽  
Carla Schmidt
Keyword(s):  
Mass Spectrometry ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Protein Complexes ◽  
Three Dimensional ◽  
Membrane Protein Complexes ◽  
Hydrophobic Nature ◽  
Alternative Approaches ◽  
Lipid Environment ◽  
And Function

Abstract Membrane proteins are key players in the cell. Due to their hydrophobic nature they require solubilising agents such as detergents or membrane mimetics during purification and, consequently, are challenging targets in structural biology. In addition, their natural lipid environment is crucial for their structure and function further hampering their analysis. Alternative approaches are therefore required when the analysis by conventional techniques proves difficult. In this review, we highlight the broad application of mass spectrometry (MS) for the characterisation of membrane proteins and their interactions with lipids. We show that MS unambiguously identifies the protein and lipid components of membrane protein complexes, unravels their three-dimensional arrangements and further provides clues of protein-lipid interactions.

Surfactant-free purification of membrane proteins with intact native membrane environment

2011 ◽  
Vol 39 (3) ◽  
pp. 813-818 ◽  
Author(s):  
Mohammed Jamshad ◽  
Yu-Pin Lin ◽  
Timothy J. Knowles ◽  
Rosemary A. Parslow ◽  
Craig Harris ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Maleic Acid ◽  
Biochemical Study ◽  
Soluble Proteins ◽  
Structure And Function ◽  
Three Dimensions ◽  
Present Review ◽  
Protein Particles ◽  
And Function

In order to study the structure and function of a protein, it is generally required that the protein in question is purified away from all others. For soluble proteins, this process is greatly aided by the lack of any restriction on the free and independent diffusion of individual protein particles in three dimensions. This is not the case for membrane proteins, as the membrane itself forms a continuum that joins the proteins within the membrane with one another. It is therefore essential that the membrane is disrupted in order to allow separation and hence purification of membrane proteins. In the present review, we examine recent advances in the methods employed to separate membrane proteins before purification. These approaches move away from solubilization methods based on the use of small surfactants, which have been shown to suffer from significant practical problems. Instead, the present review focuses on methods that stem from the field of nanotechnology and use a range of reagents that fragment the membrane into nanometre-scale particles containing the protein complete with the local membrane environment. In particular, we examine a method employing the amphipathic polymer poly(styrene-co-maleic acid), which is able to reversibly encapsulate the membrane protein in a 10 nm disc-like structure ideally suited to purification and further biochemical study.

Sign in / Sign up

Export Citation Format

Share Document