Self-assembly of protein-zwitterionic polymer bioconjugates into nanostructured materials

2016 ◽  
Vol 7 (13) ◽  
pp. 2410-2418 ◽  
Author(s):  
Dongsook Chang ◽  
Bradley D. Olsen

Bioconjugates of a red fluorescent protein mCherry and a zwitterionic polymer (PDMAPS) are self-assembled into nanostructured materials. The concentrated solution phase behaviour is studied to elucidate the effect of high charge density along the polymer backbone.

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 900 ◽  
Author(s):  
Federica Lazzari ◽  
Bruce D. Alexander ◽  
Robert M. Dalgliesh ◽  
Jenny Alongi ◽  
Elisabetta Ranucci ◽  
...  

D- and L-arginine-based polyamidoamino acids, called D- and L-ARGO7, retain the chirality and acid/base properties of the parent α-amino acids and show pH-dependent self-structuring in water. The ability of the ARGO7 chiral isomers to selectively interact with chiral biomolecules and/or surfaces was studied by choosing sodium deoxycholate (NaDC) as a model chiral biomolecule for its ability to self-assembly into globular micelles, showing enantio-selectivity. To this purpose, mixtures of NaDC with D-, L- or D,L-ARGO7, respectively, in water were analysed by circular dichroism (CD) spectroscopy and small-angle neutron scattering (SANS) at different levels of acidity expressed in terms of pD and concentrations. Differences in the CD spectra indicated chiral discrimination for NaDC/ARGO7 mixtures in the gel phase (pD 7.30) but not in the solution phase (pD 9.06). SANS measurements confirmed large scale structural perturbation induced by this chiral discrimination in the gel phase yet no modulation of the structure in the solution phase. Together, these techniques shed light on the mechanism by which ARGO7 stereoisomers modify the morphology of NaDC micelles as a function of pH. This work demonstrates chirality-dependent interactions that drive structural evolution and phase behaviour of NaDC, opening the way for designing novel smart drug delivery systems.


2019 ◽  
Vol 10 (14) ◽  
pp. 1751-1761 ◽  
Author(s):  
Takuya Suguri ◽  
Bradley D. Olsen

Bioconjugates made of the model red fluorescent protein mCherry and synthetic polymer blocks show that topology, i.e. the BA, BA2, ABA and ABC chain structure of the block copolymers, where B represents the protein and A and C represent polymers, has a significant effect on ordering transitions and the type and size of nanostructures formed during microphase separation.


2020 ◽  
Vol 48 (6) ◽  
pp. 2657-2667
Author(s):  
Felipe Montecinos-Franjola ◽  
John Y. Lin ◽  
Erik A. Rodriguez

Noninvasive fluorescent imaging requires far-red and near-infrared fluorescent proteins for deeper imaging. Near-infrared light penetrates biological tissue with blood vessels due to low absorbance, scattering, and reflection of light and has a greater signal-to-noise due to less autofluorescence. Far-red and near-infrared fluorescent proteins absorb light >600 nm to expand the color palette for imaging multiple biosensors and noninvasive in vivo imaging. The ideal fluorescent proteins are bright, photobleach minimally, express well in the desired cells, do not oligomerize, and generate or incorporate exogenous fluorophores efficiently. Coral-derived red fluorescent proteins require oxygen for fluorophore formation and release two hydrogen peroxide molecules. New fluorescent proteins based on phytochrome and phycobiliproteins use biliverdin IXα as fluorophores, do not require oxygen for maturation to image anaerobic organisms and tumor core, and do not generate hydrogen peroxide. The small Ultra-Red Fluorescent Protein (smURFP) was evolved from a cyanobacterial phycobiliprotein to covalently attach biliverdin as an exogenous fluorophore. The small Ultra-Red Fluorescent Protein is biophysically as bright as the enhanced green fluorescent protein, is exceptionally photostable, used for biosensor development, and visible in living mice. Novel applications of smURFP include in vitro protein diagnostics with attomolar (10−18 M) sensitivity, encapsulation in viral particles, and fluorescent protein nanoparticles. However, the availability of biliverdin limits the fluorescence of biliverdin-attaching fluorescent proteins; hence, extra biliverdin is needed to enhance brightness. New methods for improved biliverdin bioavailability are necessary to develop improved bright far-red and near-infrared fluorescent proteins for noninvasive imaging in vivo.


Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 186
Author(s):  
Jia-Huan Qu ◽  
Karen Leirs ◽  
Remei Escudero ◽  
Žiga Strmšek ◽  
Roman Jerala ◽  
...  

To date, surface plasmon resonance (SPR) biosensors have been exploited in numerous different contexts while continuously pushing boundaries in terms of improved sensitivity, specificity, portability and reusability. The latter has attracted attention as a viable alternative to disposable biosensors, also offering prospects for rapid screening of biomolecules or biomolecular interactions. In this context here, we developed an approach to successfully regenerate a fiber-optic (FO)-SPR surface when utilizing cobalt (II)-nitrilotriacetic acid (NTA) surface chemistry. To achieve this, we tested multiple regeneration conditions that can disrupt the NTA chelate on a surface fully saturated with His6-tagged antibody fragments (scFv-33H1F7) over ten regeneration cycles. The best surface regeneration was obtained when combining 100 mM EDTA, 500 mM imidazole and 0.5% SDS at pH 8.0 for 1 min with shaking at 150 rpm followed by washing with 0.5 M NaOH for 3 min. The true versatility of the established approach was proven by regenerating the NTA surface for ten cycles with three other model system bioreceptors, different in their size and structure: His6-tagged SARS-CoV-2 spike fragment (receptor binding domain, RBD), a red fluorescent protein (RFP) and protein origami carrying 4 RFPs (Tet12SN-RRRR). Enabling the removal of His6-tagged bioreceptors from NTA surfaces in a fast and cost-effective manner can have broad applications, spanning from the development of biosensors and various biopharmaceutical analyses to the synthesis of novel biomaterials.


FEBS Letters ◽  
2004 ◽  
Vol 577 (1-2) ◽  
pp. 227-232 ◽  
Author(s):  
Markus Fischer ◽  
Ilka Haase ◽  
Evelyn Simmeth ◽  
Günther Gerisch ◽  
Annette Müller-Taubenberger

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