9 research outputs found
Large-Scale Recombinant Production of the SARS-CoV-2 Proteome for High-Throughput and Structural Biology Applications
The highly infectious disease COVID-19 caused by the Betacoronavirus SARS-CoV-2 poses a severe threat to humanity and demands the redirection of scientific efforts and criteria to organized research projects. The international COVID19-NMR consortium seeks to provide such new approaches by gathering scientific expertise worldwide. In particular, making available viral proteins and RNAs will pave the way to understanding the SARS-CoV-2 molecular components in detail. The research in COVID19-NMR and the resources provided through the consortium are fully disclosed to accelerate access and exploitation. NMR investigations of the viral molecular components are designated to provide the essential basis for further work, including macromolecular interaction studies and high-throughput drug screening. Here, we present the extensive catalog of a holistic SARS-CoV-2 protein preparation approach based on the consortium’s collective efforts. We provide protocols for the large-scale production of more than 80% of all SARS-CoV-2 proteins or essential parts of them. Several of the proteins were produced in more than one laboratory, demonstrating the high interoperability between NMR groups worldwide. For the majority of proteins, we can produce isotope-labeled samples of HSQC-grade. Together with several NMR chemical shift assignments made publicly available on covid19-nmr.com, we here provide highly valuable resources for the production of SARS-CoV-2 proteins in isotope-labeled form
The Droserasin 1 PSI: A Membrane-Interacting Antimicrobial Peptide from the Carnivorous Plant Drosera capensis
The Droserasins, aspartic proteases from the carnivorous plant Drosera capensis, contain a 100-residue plant-specific insert (PSI) that is post-translationally cleaved and independently acts as an antimicrobial peptide. PSIs are of interest not only for their inhibition of microbial growth, but also because they modify the size of lipid vesicles and strongly interact with biological membranes. PSIs may therefore be useful for modulating lipid systems in NMR studies of membrane proteins. Here we present the expression and biophysical characterization of the Droserasin 1 PSI (D1 PSI.) This peptide is monomeric in solution and maintains its primarily α -helical secondary structure over a wide range of temperatures and pH values, even under conditions where its three disulfide bonds are reduced. Vesicle fusion assays indicate that the D1 PSI strongly interacts with bacterial and fungal lipids at pH 5 and lower, consistent with the physiological pH of D. capensis mucilage. It binds lipids with a variety of head groups, highlighting its versatility as a potential stabilizer for lipid nanodiscs. Solid-state NMR spectra collected at a field strength of 36 T, using a unique series-connected hybrid magnet, indicate that the peptide is folded and strongly bound to the membrane. Molecular dynamics simulations indicate that the peptide is stable as either a monomer or a dimer in a lipid bilayer. Both the monomer and the dimer allow the passage of water through the membrane, albeit at different rates
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Client-Chaperone Selectivity, Solubility, and Hydrogel Characteristics of Human Crystallins and the Properties of D1-PSI.
This thesis examines the properties of the human crystallin eye lens proteins from threeangles, how the structure of γS-crystallin relates to aggregation propensity, how αB-crystallin
select between aggregation prone variants, and the structure of the crystallins in a lens like
hydrogel. The human crystallins are normally highly soluble and stable, as an evolved
adaptation to maintain the transparency of the eye lens. This is due to the intrinsic stability
of the proteins themselves and the chaperone ability of the α-crystallins. By studying the
structure and biophysical properties of novel and cataract associated variants of γS-crystallin
with respect to aggregation propensity and client-chaperone interactions, it was discovered
that αB-crystallin can select between different aggregation prone and function preserving
variants, as well as a disconnect between the structural features that lead to a loss in stability
and selection as a client. In the eye lens the concentration of the crystallins can reach over
400 mg/mL. By examining pure γS-crystallin as it exists in a highly concentrated hydrogel
it was discovered that the gel is formed by the protein forming into larger order oligomers in
the form of filaments and amorphous domains, but the domains retain a high degree of liquid
like character. Lastly the properties of the plant specific insert (PSI) from Drosera capensis
were examined. It was discovered that this protein exhibits anti-microbial properties, likely stemming from the fact that PSI can destabilize cell membranes and readily forms complexes
with lipids
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α-Crystallins in the Vertebrate Eye Lens: Complex Oligomers and Molecular Chaperones
α-Crystallins are small heat-shock proteins that act as holdase chaperones. In humans, αA-crystallin is expressed only in the eye lens, while αB-crystallin is found in many tissues. α-Crystallins have a central domain flanked by flexible extensions and form dynamic, heterogeneous oligomers. Structural models show that both the C- and N-terminal extensions are important for controlling oligomerization through domain swapping. α-Crystallin prevents aggregation of damaged β- and γ-crystallins by binding to the client protein using a variety of binding modes. α-Crystallin chaperone activity can be compromised by mutation or posttranslational modifications, leading to protein aggregation and cataract. Because of their high solubility and their ability to form large, functional oligomers, α-crystallins are particularly amenable to structure determination by solid-state nuclear magnetic resonance (NMR) and solution NMR, as well as cryo-electron microscopy
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Human αB-crystallin discriminates between aggregation-prone and function-preserving variants of a client protein.
BackgroundThe eye lens crystallins are highly soluble proteins that are required to last the lifespan of an organism due to low protein turnover in the lens. Crystallin aggregation leads to formation of light-scattering aggregates known as cataract. The G18V mutation of human γS-crystallin (γS-G18V), which is associated with childhood-onset cataract, causes structural changes throughout the N-terminal domain and increases aggregation propensity. The holdase chaperone protein αB-crystallin does not interact with wild-type γS-crystallin, but does bind its G18V variant. The specific molecular determinants of αB-crystallin binding to client proteins is incompletely charcterized. Here, a new variant of γS, γS-G18A, was created to test the limits of αB-crystallin selectivity.MethodsMolecular dynamics simulations were used to investigate the structure and dynamics of γS-G18A. The overall fold of γS-G18A was assessed by circular dichroism (CD) spectroscopy and intrinsic tryptophan fluorescence. Its thermal unfolding temperature and aggregation propensity were characterized by CD and DLS, respectively. Solution-state NMR was used to characterize interactions between αB-crystallin and γS-G18A.ResultsγS-G18A exhibits minimal structural changes, but has compromised thermal stability relative to γS-WT. The placement of alanine, rather than valine, at this highly conserved glycine position produces minor changes in hydrophobic surface exposure. However, human αB-crystallin does not bind the G18A variant, in contrast to previous observations for γS-G18V, which aggregates at physiological temperature.ConclusionsαB-crystallin is capable of distinguishing between aggregation-prone and function-preserving variants, and recognizing the transient unfolding or minor conformers that lead to aggregation in the disease-related variant.General significanceHuman αB-crystallin distinguishes between highly similar variants of a structural crystallin, binding the cataract-related γS-G18V variant, but not the function-preserving γS-G18A variant, which is monomeric at physiological temperature
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Deamidation of the human eye lens protein γS-crystallin accelerates oxidative aging
Cataract, a clouding of the eye lens from protein precipitation, affects millions of people every year. The lens proteins, the crystallins, show extensive post-translational modifications (PTMs) in cataractous lenses. The most common PTMs, deamidation and oxidation, promote crystallin aggregation; however, it is not clear precisely how these PTMs contribute to crystallin insolubilization. Here, we report six crystal structures of the lens protein γS-crystallin (γS): one of the wild-type and five of deamidated γS variants, from three to nine deamidation sites, after sample aging. The deamidation mutations do not change the overall fold of γS; however, increasing deamidation leads to accelerated disulfide-bond formation. Addition of deamidated sites progressively destabilized protein structure, and the deamidated variants display an increased propensity for aggregation. These results suggest that the deamidated variants are useful as models for accelerated aging; the structural changes observed provide support for redox activity of γS-crystallin in the lens
Large-Scale Recombinant Production of the SARS-CoV-2 Proteome for High-Throughput and Structural Biology Applications
The highly infectious disease COVID-19 caused by the Betacoronavirus SARS-CoV-2 poses a severe threat to humanity and demands the redirection of scientific efforts and criteria to organized research projects. The international COVID19-NMR consortium seeks to provide such new approaches by gathering scientific expertise worldwide. In particular, making available viral proteins and RNAs will pave the way to understanding the SARS-CoV-2 molecular components in detail. The research in COVID19-NMR and the resources provided through the consortium are fully disclosed to accelerate access and exploitation. NMR investigations of the viral molecular components are designated to provide the essential basis for further work, including macromolecular interaction studies and high-throughput drug screening. Here, we present the extensive catalog of a holistic SARS-CoV-2 protein preparation approach based on the consortium’s collective efforts. We provide protocols for the large-scale production of more than 80% of all SARS-CoV-2 proteins or essential parts of them. Several of the proteins were produced in more than one laboratory, demonstrating the high interoperability between NMR groups worldwide. For the majority of proteins, we can produce isotope-labeled samples of HSQC-grade. Together with several NMR chemical shift assignments made publicly available on covid19-nmr.com, we here provide highly valuable resources for the production of SARS-CoV-2 proteins in isotope-labeled form.This work was supported by Goethe University (Corona funds),
the DFG-funded CRC: “Molecular Principles of RNA-Based
Regulation,” DFG infrastructure funds (project numbers:
277478796, 277479031, 392682309, 452632086, 70653611), the
state of Hesse (BMRZ), the Fondazione CR Firenze (CERM),
and the IWB-EFRE-program 20007375. This project has
received funding from the European Union’s Horizon 2020
research and innovation program under Grant Agreement No.
871037. AS is supported by DFG Grant SCHL 2062/2-1 and by the
JQYA at Goethe through project number 2019/AS01. Work in the
lab of KV was supported by a CoRE grant from the University of
New Hampshire. The FLI is a member of the Leibniz Association
(WGL) and financially supported by the Federal Government of
Germany and the State of Thuringia. Work in the lab of RM was
supported by NIH (2R01EY021514) and NSF (DMR-2002837).
BN-B was supported by theNSF GRFP.MCwas supported byNIH
(R25 GM055246 MBRS IMSD), and MS-P was supported by the
HHMI Gilliam Fellowship. Work in the labs of KJ and KT was
supported by Latvian Council of Science Grant No. VPP-COVID
2020/1-0014. Work in the UPAT’s lab was supported by the
INSPIRED (MIS 5002550) project, which is implemented under
the Action “Reinforcement of the Research and Innovation
Infrastructure,” funded by the Operational Program
“Competitiveness, Entrepreneurship and Innovation” (NSRF
2014–2020) and cofinanced by Greece and the EU (European
Regional Development Fund) and the FP7 REGPOT CT-2011-
285950–“SEE-DRUG” project (purchase of UPAT’s 700MHz
NMR equipment). Work in the CM-G lab was supported by
the Helmholtz society. Work in the lab of ABö was supported
by the CNRS, the French National Research Agency (ANR, NMRSCoV2-
ORF8), the Fondation de la Recherche Médicale (FRM,
NMR-SCoV2-ORF8), and the IR-RMN-THC Fr3050 CNRS.
Work in the lab of BM was supported by the Swiss National
Science Foundation (Grant number 200020_188711), the
Günthard Stiftung für Physikalische Chemie, and the ETH
Zurich. Work in the labs of ABö and BM was supported by a
common grant from SNF (grant 31CA30_196256). This work was
supported by the ETHZurich, the grant ETH40 18 1, and the grant
Krebsliga KFS 4903 08 2019. Work in the lab of the IBS Grenoble
was supported by the Agence Nationale de Recherche (France)
RA-COVID SARS2NUCLEOPROTEIN and European Research
Council Advanced Grant DynamicAssemblies. Work in the
CA lab was supported by Patto per il Sud della Regione
Siciliana–CheMISt grant (CUP G77B17000110001). Part of
this work used the platforms of the Grenoble Instruct-ERIC
center (ISBG; UMS 3518 CNRS-CEA-UGA-EMBL) within the
Grenoble Partnership for Structural Biology (PSB), supported
by FRISBI (ANR-10-INBS-05-02) and GRAL, financed within
the University Grenoble Alpes graduate school (Ecoles
Universitaires de Recherche) CBH-EUR-GS (ANR-17-EURE-
0003). Work at the UW-Madison was supported by grant
numbers NSF MCB2031269 and NIH/NIAID AI123498. MM
is a Ramón y Cajal Fellow of the Spanish AEI-Ministry of
Science and Innovation (RYC2019-026574-I), and a “La
Caixa” Foundation (ID 100010434) Junior Leader Fellow
(LCR/BQ/PR19/11700003). Funded by project COV20/00764
fromthe Carlos III Institute of Health and the SpanishMinistry
of Science and Innovation to MMand DVL. VDJ was supported
by the Boehringer Ingelheim Fonds. Part of this work used the
resources of the Italian Center of Instruct-ERIC at the CERM/
CIRMMP infrastructure, supported by the Italian Ministry for
University and Research (FOE funding). CF was supported by
the Stiftung Polytechnische Gesellschaft. Work in the lab of
JH was supported by NSF (RAPID 2030601) and NIH
(R01GM123249).Peer reviewe