Flexibility is the ability of a power system to respond to changes in power demand and generation. Integrating large shares of variable renewable energy sources, in particular wind and solar, can ...lead to a strong increase of flexibility requirements for the complementary system, traditionally hydrothermal, which has to balance the fluctuations of variable generation. We quantify these flexibility requirements at the operational timescale of 1–12 hours and different spatial scales across Europe. Our results indicate that three major factors determine the ramping flexibility needed in future power systems: the penetration of variable renewables, their mix and the geographic system size. Compared to the variability of load, flexibility requirements increase strongly in systems with combined wind and PV (photovoltaics) contribution of more than 30% of total energy and a share of PV in the renewables mix above 20–30%. In terms of extreme ramps, the flexibility requirements of a geographically large, transnational power system are significantly lower than of smaller regional systems, especially at high wind penetration.
•We assess power system flexibility needs at different temporal and spatial scales.•Flexibility requirements depend on share of renewables, their mix and system size.•Reductions in net load ramp rates can be achieved through larger system size.•Ramps go up with wind/PV above 30% of demand and PV in renewables mix above 20–30%.•Move toward a general method to assess future flexibility needs in power systems.
The nature of the first prebiotic compartments and their possible minimal molecular composition is of great importance in the origin of life scenarios. Current protocell model membranes are proposed ...to be lipid-based. This paradigm has several shortcomings such as limited membrane stability of monoacyl lipid-based membranes (e.g., fatty acids), missing pathways to synthesize protocell membrane components (e.g., phospholipids) under early earth conditions, and the requirement for different classes of molecules for the formation of compartments and the catalysis of reactions. Amino acids on the other hand are known to arise and persist with remarkable abundance under early earth conditions since the fundamental Miller–Urey experiments. They were also postulated early to form protocellular structures, for example, proteinoid capsules. Here, we present a protocell model constituted by membranes assembled from amphiphilic proteins based on prebiotic amino acids. Self-assembled dynamic protein membrane-based compartments (PMBCs) are impressively stable and compatible with prevalent cellular membrane constituents forming protein-only or protein–lipid hybrid membranes. They can embed processes essential for extant living cells, such as enclosure of molecules, membrane fusion, phase separation, and complex biosynthetic elements from modern cells demonstrating “upward” compatibility. Our findings suggest that prebiotic PMBCs represent a new type of protocell as a possible ancestor of current lipid-based cells. The presented prebiotic PMBC model can be used to design artificial cells, important for the study of structural, catalytic, and evolutionary pathways related to the emergence of life.
Life in its molecular context is characterized by the challenge of orchestrating structure, energy and information processes through compartmentalization and chemical transformations amenable to ...mimicry of protocell models. Here we present an alternative protocell model incorporating dynamic membranes based on amphiphilic elastin‐like proteins (ELPs) rather than phospholipids. For the first time we demonstrate the feasibility of combining vesicular membrane formation and biocatalytic activity with molecular entities of a single class: proteins. The presented self‐assembled protein‐membrane‐based compartments (PMBCs) accommodate either an anabolic reaction, based on free DNA ligase as an example of information transformation processes, or a catabolic process. We present a catabolic process based on a single molecular entity combining an amphiphilic protein with tobacco etch virus (TEV) protease as part of the enclosure of a reaction space and facilitating selective catalytic transformations. Combining compartmentalization and biocatalytic activity by utilizing an amphiphilic molecular building block with and without enzyme functionalization enables new strategies in bottom‐up synthetic biology, regenerative medicine, pharmaceutical science and biotechnology.
A generalizable molecular platform for minimalist cell design: Essential features of extant cells include compartmentalization and biocatalytic activity. In this context we designed a minimal cell system in which the protocellular membrane was made up solely of protein components, by use of amphiphilic block‐domain elastin‐like proteins together with free or conjugated enzymes.
The molecular structuring of complex architectures and the enclosure of space are essential requirements for technical and living systems. Self‐assembly of supramolecular structures with desired ...shape, size, and stability remains challenging since it requires precise regulation of physicochemical and conformational properties of the components. Here a general platform for controlled self‐assembly of tailored amphiphilic elastin‐like proteins into desired supramolecular protein assemblies ranging from spherical coacervates over molecularly defined twisted fibers to stable unilamellar vesicles is introduced. The described assembly protocols efficiently yield protein membrane–based compartments (PMBC) with adjustable size, stability, and net surface charge. PMBCs demonstrate membrane fusion and phase separation behavior and are able to encapsulate structurally and chemically diverse cargo molecules ranging from small molecules to naturally folded proteins. The ability to engineer tailored supramolecular architectures with defined fusion behavior, tunable properties, and encapsulated cargo paves the road for novel drug delivery systems, the design of artificial cells, and confined catalytic nanofactories.
A platform of environmentally controlled architectures ranging from twisted fibers to stable vesicles is demonstrated. Supramolecular architectures are designed via a library of amphiphilic elastin‐like proteins (ELPs). Tailored ELPs, responsive to environmental parameters enable the assembly of complex materials with tunable properties. The described assembly protocols yield Protein Membrane‐Based Compartments enabling the encapsulation of delicate cargo.
The control of supramolecular complexes in living systems at the molecular level is an important goal in life-sciences. Spatiotemporal organization of molecular distribution & flow of such complexes ...are essential physicochemical processes in living cells and important for pharmaceutical processes. Membraneless organelles (MO) found in eukaryotic cells, formed by liquid-liquid phase-separation (LLPS) of intrinsically disordered proteins (IDPs) control and adjust intracellular organization. Artificially designed compartments based on LLPS open up a novel pathway to control chemical flux and partition in vitro and in vivo. We designed a library of chemically precisely defined block copolymer-like proteins based on elastin-like proteins (ELPs) with defined charge distribution and type, as well as polar and hydrophobic block domains. This enables the programmability of physicochemical properties and to control adjustable LLPS in vivo attaining control over intracellular partitioning and flux as role model for in vitro and in vivo applications. Tailor-made ELP-like block copolymer proteins exhibiting IDP-behavior enable LLPS formation in vitro and in vivo allowing the assembly of membrane-based and membraneless superstructures via protein phase-separation in E. coli. Subsequently, we demonstrate the responsiveness of protein phase-separated spaces (PPSSs) to environmental physicochemical triggers and their selective, charge-dependent and switchable interaction with DNA or extrinsic and intrinsic molecules enabling their selective shuttling across semipermeable phase boundaries including (cell)membranes. This paves the road for adjustable artificial PPSS-based storage and reaction spaces and the specific transport across phase boundaries for applications in pharmacy and synthetic biology.
•An amphiphilic protein (aELP) library allows for adjustable compartments in vivo.•Extrinsic stimuli modulate protein-phase separated spaces (PPSS) in E. coli.•PPSS formed by charged aELPs direct DNA localization.•Charged aELP forming PPSS can control molecular flux of molecules in vivo.•Responsive PPSS can be used in pharmaceutical applications and synthetic biology.
Nanoscale biological materials formed by the assembly of defined block-domain proteins control the formation of cellular compartments such as organelles. Here, we introduce an approach to ...intentionally 'program' the de novo synthesis and self-assembly of genetically encoded amphiphilic proteins to form cellular compartments, or organelles, in Escherichia coli. These proteins serve as building blocks for the formation of artificial compartments in vivo in a similar way to lipid-based organelles. We investigated the formation of these organelles using epifluorescence microscopy, total internal reflection fluorescence microscopy and transmission electron microscopy. The in vivo modification of these protein-based de novo organelles, by means of site-specific incorporation of unnatural amino acids, allows the introduction of artificial chemical functionalities. Co-localization of membrane proteins results in the formation of functionalized artificial organelles combining artificial and natural cellular function. Adding these protein structures to the cellular machinery may have consequences in nanobiotechnology, synthetic biology and materials science, including the constitution of artificial cells and bio-based metamaterials.
Adding a new dimension: 4D or 3D proton‐detected spectra of perdeuterated protein samples with 1H labelled amides and methyl groups permit collecting unambiguous distance restraints with high ...sensitivity and determining protein structure by solid‐state NMR (see picture).
The control over the defined assembly of nano-objects with nm-precision is important to create systems and materials with enhanced properties, for example, metamaterials. In nature, the precise ...assembly of inorganic nano-objects with unique features, for example, magnetosomes, is accomplished by efficient and reliable recognition schemes involving protein effectors. Here we present a molecular approach using protein-based 'adaptors/connectors' with genetically encoded interaction sites to guide the assembly and functionality of different plasmonically active gold nanoparticle architectures (AuNP). The interaction of the defined geometricaly shaped protein adaptors with the AuNP induces the self-assembly of nanoarchitectures ranging from AuNP encapsulation to one-dimensional chain-like structures, complex networks and stars. Synthetic biology and bionanotechnology are applied to co-translationally encode unnatural amino acids as additional site-specific modification sites to generate functionalized biohybrid nanoarchitectures. This protein adaptor-based nano-object assembly approach might be expanded to other inorganic nano-objects creating biohybrid materials with unique electronic, photonic, plasmonic and magnetic properties.
Elastin‐like proteins (ELPs) are biologically important proteins and models for intrinsically disordered proteins (IDPs) and dynamic structural transitions associated with coacervates and ...liquid–liquid phase transitions. However, the conformational status below and above coacervation temperature and its role in the phase separation process is still elusive. Employing matrix least‐squares global Boltzmann fitting of the circular dichroism spectra of the ELPs (VPGVG)20, (VPGVG)40, and (VPGVG)60, we found that coacervation occurs sharply when a certain number of repeat units has acquired β‐turn conformation (in our sequence setting a threshold of approx. 20 repeat units). The character of the differential scattering of the coacervate suspensions indicated that this fraction of β‐turn structure is still retained after polypeptide assembly. Such conformational thresholds may also have a role in other protein assembly processes with implications for the design of protein‐based smart materials.
Elastin‐like proteins (ELPs) undergo reversible coacervation above a certain transition temperature. The thermodynamic analysis of temperature‐dependent circular dichroism of ELPs of different chain‐length revealed that this is preceded by a step‐by‐step increase of β‐turn structure. When a certain threshold is reached, phase separation occurs. The conformational ratio in the assembled protein particles still corresponds to this threshold.
Inflammasomes are multiprotein complexes that control the innate immune response by activating caspase-1, thus promoting the secretion of cytokines in response to invading pathogens and endogenous ...triggers. Assembly of inflammasomes is induced by activation of a receptor protein. Many inflammasome receptors require the adapter protein ASC apoptosis-associated speck-like protein containing a caspase-recruitment domain (CARD), which consists of two domains, the N-terminal pyrin domain (PYD) and the C-terminal CARD. Upon activation, ASC forms large oligomeric filaments, which facilitate procaspase-1 recruitment. Here, we characterize the structure and filament formation of mouse ASC in vitro at atomic resolution. Information from cryo-electron microscopy and solid-state NMR spectroscopy is combined in a single structure calculation to obtain the atomic-resolution structure of the ASC filament. Perturbations of NMR resonances upon filament formation monitor the specific binding interfaces of ASC-PYD association. Importantly, NMR experiments show the rigidity of the PYD forming the core of the filament as well as the high mobility of the CARD relative to this core. The findings are validated by structure-based mutagenesis experiments in cultured macrophages. The 3D structure of the mouse ASC-PYD filament is highly similar to the recently determined human ASC-PYD filament, suggesting evolutionary conservation of ASC-dependent inflammasome mechanisms.
PDF
