Topological Effects on Globular Protein‐ELP Fusion Block Copolymer Self‐Assembly

Qin, Guokui; Glassman, Matthew; Lam, Christopher N.; Chang, Dongsook; Schaible, Eric; Hexemer, Alexander; Olsen, Bradley D.

doi:10.1002/adfm.201403453

Cited by 42 publications

(56 citation statements)

References 58 publications

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“…CD is a common method for the analysis of protein conformation . To further verify the validity of the above‐mentioned results, CD spectroscopy is performed to monitor the secondary structure changes of PrP during the conformational transformation ( Figure ).…”

Section: Resultsmentioning

confidence: 99%

Plasmon‐Enhanced Fluorescent Sensor based on Aggregation‐Induced Emission for the Study of Protein Conformational Transformation

Cui

Chang

Tan

et al. 2019

Adv Funct Materials

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The alteration in protein conformation not only affects the performance of its biological functions, but also leads to a variety of protein‐mediated diseases. Developing a sensitive strategy for protein detection and monitoring its conformation changes is of great significance for the diagnosis and treatment of protein conformation diseases. Herein, a plasmon‐enhanced fluorescence (PEF) sensor is developed, based on an aggregation‐induced emission (AIE) molecule to monitor conformational changes in protein, using prion protein as a model. Three anthracene derivatives with AIE characteristics are synthesized and a water‐miscible sulfonate salt of 9,10‐bis(2‐(6‐sulfonaphthalen‐2‐yl)vinyl)anthracene (BSNVA) is selected to construct the PEF–AIE sensor. The sensor is nearly non‐emissive when it is mixed with cellular prion protein while emits fluorescence when mixed with disease‐associated prion protein (PrPSc). The kinetic process of conformational conversion can be monitored through the fluorescence changes of the PEF–AIE sensor. By right of the amplified fluorescence signal, this PEF–AIE sensor can achieve a detection limit 10 pM lower than the traditional AIE probe and exhibit a good performance in human serum sample. Furthermore, molecular docking simulations suggest that BSNVA tends to dock in the β‐sheet structure of PrP by hydrophobic interaction between BSNVA and the exposed hydrophobic residues.

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Section: Resultsmentioning

confidence: 99%

Plasmon‐Enhanced Fluorescent Sensor based on Aggregation‐Induced Emission for the Study of Protein Conformational Transformation

Cui

Chang

Tan

et al. 2019

Adv Funct Materials

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“…From the evidences that the histidine residue, despite its stabilizing effect, is positively evolved in T3SS effectors, and plays an eminent role in folding and stability of AvrPto (8), ExoY, and other T3SS effectors, it is clear that histidine-mediated stabilizing interactions in T3SS effectors plausibly act as pH-sensing folding switches to regulate effector protein folding and stability in a spatial-temporal manner. In addition, T3SS effector proteins have evolved abundant gate-keeper residues and LCR promoting residues in their sequence space to prevent initiation of amyloid-like aggregation and to maintain a fine balance in folding, solubility, and stability (48,49,53). Lastly, from a detailed analysis of all facts and phenomena, it can be curtained that T3SS effectors belong to typical class (disorder globules) of IDPs and have evolved intrinsic disordered properties to facilitate their unfolding and secretion via nano-size pore of T3SS injectisome.…”

Section: Resultsmentioning

confidence: 99%

Deciphering the structural intricacy in virulence effectors for proton-motive force mediated unfolding and type-III protein secretion

Khanppnavar

Roy

Chandra

et al. 2019

Preprint

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ABSTRACTMany gram-negative pathogenic bacteria use type III secretion system (T3SS) to inject virulence effectors directly into the cytosol of targeted host cells. Given that the protein unfolding requisite for secretion via nano-size pore of T3SS injectisome is an energetically unfavorable process, “How do pathogenic bacteria unfold and secrete hundreds of toxic proteins in seconds” remain largely unknown. In this study, first, from an in-depth analysis of folding and stability of T3SS effector ExoY, we show that the proton-concentration gradient (∼pH 5.8-6.0) generated by proton-motive force (PMF) can significantly amortize tertiary structural folding and stability of effectors without significant entropic cost. Strikingly, it was found that the lower energetic cost associated with the global unfolding of ExoY is mainly due to its weakly folded geometry and abundance of geometrical frustrations stemming from buried water molecules and native-like folded intermediates in the folded cores. From in-silico structural analysis of 371 T3SS effectors, it can be curtained that T3SS effectors belong to typical class (disorder globules) of IDPs and have evolved similar conserved intrinsic structural archetypes to mediate early-stage unfolding. The slower folding kinetics in effector proteins requisite for efficient T3SS-mediated secretion mostly stems from reduced hydrophobic density and enhanced polar-polar repulsive interactions in their sequence landscapes. Lastly, the positively evolved histidine-mediated stabilizing interactions and gate-keeper residues in effector proteins shed light on collaborative role of evolved structural chemistry in T3SS effectors and PMF in the spatial-temporal regulation of effector folding and stability essential for maintaining balance in secretion and function trade-off.

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“…As thermoresponsive behavior is a hallmark of elastin‐based materials, the turbidity of SELP nanogel solutions was analyzed over increasing and decreasing temperatures to obtain thermal phase transition temperatures ( T t ) ( Figure 4 ). The silk‐to‐elastin ratio and sequence of the SELP impacted nanogel T t , with 415K‐S nanogels exhibiting a significantly lower transition temperature than either 47K‐S or 815K‐S nanogels ( Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

Self‐Assembly of Thermoresponsive Recombinant Silk‐Elastinlike Nanogels

Isaacson

Jensen

Watanabe

et al. 2017

Macromolecular Bioscience

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strength to SELPs, while elastin units provide lower critical solution temperature (LCST)-based elastomeric activity. [2,3] The LCST behavior induces a disorder-to-order transition that renders SELPs a viable option for macroscale applications such as temperature-induced liquid-to-solid transarterial chemoembolics, [4,5] in situ gelling enemas, [6] localized hydrogel drug and adenovirus release matrices, [7,8] 3D tissue engineering scaffolds, [9] and crosslinked protein films. [10] The ratio and sequence of silk and elastin motifs allows for a high degree of control over gelation properties and material strength. [11] Furthermore, responsive peptide sequences can be inserted into the poly mer backbone to achieve biodegradation and controlled release. [12] While SELP hydrogels have been extensively investigated for controlled delivery of bioactive agents, very limited research involving the design and development of SELP nanoparticles has been accomplished. Recent work reports the use of self-assembly techniques to achieve micelle formation with SELPs with drug-loading capabilities, [13,14] controlling size via silk-to-elastin ratio. [15] When SELPs with His tags were used to coat nickel-functionalized plasmonic gold nanoparticles, hexamer number proved highly influential on overall particle size. [16] These SELP-coated nanoparticles exhibited reversible, thermally induced aggregation, allowing for a thermal on-off switch between individual and collective plasmon resonances. Self-assembly of SELPs has also been accomplished for nanofiber formation, using both surfaceinduced and nanomechanical stimuli. [17,18] It was shown that the formation frequency of sphere-like aggregates over nanofibers increased with increasing solvent ionic strength. [17] Optimization of silk and elastin block lengths resulted in a core-sheath nanofiber structure (silk in the core, elastin in the sheath). [19] While self-assembly and design techniques have allowed for the creation of micelle-like, coated nanoparticle, and nanofiber structures, cases of self-assembled, physically crosslinked SELP nanogels have yet to be reported. Nanogels are nanoscale polymer networks bound together via crosslinks between individual polymer chains and differ substantially from other nanoparticle structures, such as micelles (Figure 1a). Crosslinks can be formed via covalent or physical bonds and provide overall structural stability. [20] In drug delivery, nanogel systems have been shown to achieve high drug loading efficiency (up to 30 wt%), often outcompeting Silk-Elastinlike Protein NanogelsRecombinant silk-elastinlike protein polymers (SELPs) combine the biocompatibility and thermoresponsiveness of human tropoelastin with the strength of silk. Direct control over structure of these monodisperse polymers allows for precise correlation of structure with function. This work describes the fabrication of the first SELP nanogels and evaluation of their physicochemical properties and thermoresponsiveness. Self-assembly of dilute concentrations of SELPs results...

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Topological Effects on Globular Protein‐ELP Fusion Block Copolymer Self‐Assembly

Cited by 42 publications

References 58 publications

Plasmon‐Enhanced Fluorescent Sensor based on Aggregation‐Induced Emission for the Study of Protein Conformational Transformation

Plasmon‐Enhanced Fluorescent Sensor based on Aggregation‐Induced Emission for the Study of Protein Conformational Transformation

Deciphering the structural intricacy in virulence effectors for proton-motive force mediated unfolding and type-III protein secretion

Self‐Assembly of Thermoresponsive Recombinant Silk‐Elastinlike Nanogels

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