Browsing by Author "Patkar, Sai S."
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Item Genetic Fusion of Thermoresponsive Polypeptides with UCST-type Behavior Mediates 1D Assembly of Coiled-Coil Bundlemers(Angewandte Chemie International Edition, 2023-05-09) Patkar, Sai S.; Tang, Yao; Bisram, Arriana M.; Zhang, Tianren; Saven, Jeffery G.; Pochan, Darrin J.; Kiick, Kristi L.Graphical Abstract: Available at: https://doi.org/10.1002/anie.202301331 Computationally designed coiled coil-forming peptides were functionalized with thermoresponsive resilin-like polypeptides (RLPs) of various lengths and produced via biosynthetic methods in bacterial expression hosts. Interactions between RLPs upon cooling below their upper critical solution temperature (UCST) resulted in nanofibrillar assembly. Abstract Thermoresponsive resilin-like polypeptides (RLPs) of various lengths were genetically fused to two different computationally designed coiled coil-forming peptides with distinct thermal stability, to develop new strategies to assemble coiled coil peptides via temperature-triggered phase separation of the RLP units. Their successful production in bacterial expression hosts was verified via gel electrophoresis, mass spectrometry, and amino acid analysis. Circular dichroism (CD) spectroscopy, ultraviolet-visible (UV/Vis) turbidimetry, and dynamic light scattering (DLS) measurements confirmed the stability of the coiled coils and showed that the thermosensitive phase behavior of the RLPs was preserved in the genetically fused hybrid polypeptides. Cryogenic-transmission electron microscopy and coarse-grained modeling revealed that functionalizing the coiled coils with thermoresponsive RLPs leads to their thermally triggered noncovalent assembly into nanofibrillar assemblies.Item Sequence-Encoded Differences in Phase Separation Enable Formation of Resilin-like Polypeptide-Based Microstructured Hydrogels(Biomacromolecules, 2023-08-14) Patkar, Sai S.; Garcia, Cristobal Garcia; Palmese, Luisa L.; Kiick, Kristi L.Microstructured hydrogels are promising platforms to mimic structural and compositional heterogeneities of the native extracellular matrix (ECM). The current state-of-the-art soft matter patterning techniques for generating ECM mimics can be limited owing to their reliance on specialized equipment and multiple time- and energy-intensive steps. Here, a photocross-linking methodology that traps various morphologies of phase-separated multicomponent formulations of compositionally distinct resilin-like polypeptides (RLPs) is reported. Turbidimetry and quantitative 1H NMR spectroscopy were utilized to investigate the sequence-dependent liquid–liquid phase separation of multicomponent solutions of RLPs. Differences between the intermolecular interactions of two different photocross-linkable RLPs and a phase-separating templating RLP were exploited for producing microstructured hydrogels with tunable control over pore diameters (ranging from 1.5 to 150 μm) and shear storage moduli (ranging from 0.2 to 5 kPa). The culture of human mesenchymal stem cells demonstrated high viability and attachment on microstructured hydrogels, suggesting their potential for developing customizable platforms for regenerative medicine applications.