Adaptive Recombinant Nanoworms from Genetically Encodable Star Amphiphiles

Abstract

Recombinant nanoworms are promising candidates for materials and biomedical applications ranging from the templated synthesis of nanomaterials to multivalent display of bioactive peptides and targeted delivery of theranostic agents. However, molecular design principles to synthesize these assemblies (which are thermodynamically favorable only in a narrow region of the phase diagram) remain unclear. To advance the identification of design principles for the programmable assembly of proteins into well-defined nanoworms and to broaden their stability regimes, we were inspired by the ability of topologically engineered synthetic macromolecules to acess rare mesophases. To test this design principle in biomacromolecular assemblies, we used post-translational modifications (PTMs) to generate lipidated proteins with precise topological and compositional asymmetry. Using an integrated experimental and computational approach, we show that the material properties (thermoresponse and nanoscale assembly) of these hybrid amphiphiles are modulated by their amphiphilic architecture. Importantly, we demonstrate that the judicious choice of amphiphilic architecture can be used to program the assembly of proteins into adaptive nanoworms, which undergo a morphological transition (sphere-to-nanoworms) in response to temperature stimuli.

Temperature-Responsive Nano-Biomaterials from Genetically Encoded Farnesylated Disordered Proteins

“…By combining biophysical and soft-matter characterization techniques, we show that farnesylation alters the thermoresponse, phase separation, and assembly of ELPs used as model systems. Dynamic light scattering and cryo-TEM show that the farnesylated ELP assemblies exist in a dynamic equilibrium between unimers and assembled structures, a behavior distinct from the assemblies of ELPs modified with other lipids, such as saturated fatty acids 66 or sterols. 42 We propose that increased dynamics of ELP-Fr micellar assemblies is due to the reduced hydrophobicity and packing efficiency of the unsaturated farnesyl group.…”

Encoding Structure in Intrinsically Disordered Protein Biomaterials

“…Hossain et al synthesized lipidated ELP constructs with nonlinear architecture termed star-shaped amphiphilic fatty acid-modified ELPs (SAFEs), composed of three distinct elements: ELP arms, branch point, and lipid . The topologically asymmetric design involved two different ELP armsa hydrophobic arm, (VPGVG) 40 , and a hydrophilic arm, (VPGSG) 60 to control the extent of aggregation.…”

“…Hossain et al synthesized lipidated ELP constructs with nonlinear architecture termed star-shaped amphiphilic fatty acid-modified ELPs (SAFEs), composed of three distinct elements: ELP arms, branch point, and lipid. 53 The topologically asymmetric design involved two different ELP arms�a hydrophobic arm, (VPGVG) 40 , and a hydrophilic arm, (VPGSG) 60 �to control the extent of aggregation. The branched topology was achieved by genetically encoding SpyTag at the interface between the hydrophobic and hydrophilic arms and SpyCatcher at the C-terminus of another (VPGVG) 40 hydrophobic block.…”

Lipidation Alters the Structure and Hydration of Myristoylated Intrinsically Disordered Proteins

“…Utilization of PTMs offers a promising direction for the construction of hybrid protein materials with diversified physicochemical properties, expanded engineering capabilities, and/or altered biological behavior. − For instance, lipidation of stimuli-responsive intrinsically disordered proteins (IDPs) has been used to combine the hierarchical assembly of lipids with the temperature-responsiveness of IDPs to create assemblies whose nano- and mesoscale structure can change with temperature. − Specifically, fatty-acid-modified elastin-like polypeptides (FAMEs) can form a diverse palette of spherical and anisotropic structures as a function of temperature including spherical nanoparticles ,, that can change size or transition into nanoworms or fibers . The ability to reprogram the nanoassembly of these hybrid biomaterials as a function of temperature is desirable for biomedical applications, including drug delivery. , Because temperature can be easily and precisely modulated as a therapeutic modality, this thermoresponsiveness can be harnessed to regulate the transport and localization of carriers and encapsulated drugs while causing minimal damage to healthy tissues …”

“…22−24 For instance, lipidation of stimuli-responsive intrinsically disordered proteins (IDPs) has been used to combine the hierarchical assembly of lipids with the temperature-responsiveness of IDPs to create assemblies whose nano-and mesoscale structure can change with temperature. 25−28 Specifically, fatty-acid-modified elastinlike polypeptides (FAMEs) can form a diverse palette of spherical and anisotropic structures as a function of temperature including spherical nanoparticles 26,29,30 that can change size 31 or transition into nanoworms 32 or fibers. 33 The ability to reprogram the nanoassembly of these hybrid biomaterials as a function of temperature is desirable for biomedical applications, including drug delivery.…”