Photoresponsive Polypeptide Research Articles

Synthesis of modifiable photo-responsive polypeptides bearing allyloxyazobenzene side-chains

A photo-responsive and modifiable polypeptide with stable helical conformation was synthesized. The self-assembly and liquid crystalline phase structure were subsequently studied.

Light- and Metal Ion-Induced Self-Assembly and Reassembly Based on Block Copolymers Containing a Photoresponsive Polypeptide Segment

Because of the advantageous properties, the photoresponsive bioinspired polymers are of great interest for many applications. In this study, we synthesized a new family of photoresponsive poly(ethy...

3D-extrusion printing of stable constructs composed of photoresponsive polypeptide hydrogels

Printing of novel linear polypeptide hydrogel bioinks and stabilisation of structures by post-printing UV-triggered crosslinking through catalyst free thiol–yne click chemistry of cysteine and propiolated 4-arm PEG.

Progress in Photo-Responsive Polypeptide Derived Nano-Assemblies.

Stimuli-responsive polymeric materials have attracted significant attention in a variety of high-value-added and industrial applications during the past decade. Among various stimuli, light is of particular interest as a stimulus because of its unique advantages, such as precisely spatiotemporal control, mild conditions, ease of use, and tunability. In recent years, a lot of effort towards the synthesis of a biocompatible and biodegradable polypeptide has resulted in many examples of photo-responsive nanoparticles. Depending on the specific photochemistry, those polypeptide derived nano-assemblies are capable of crosslinking, disassembling, or morphing into other shapes upon light irradiation. In this review, we aim to assess the current state of photo-responsive polypeptide based nanomaterials. Firstly, those ‘smart’ nanomaterials will be categorized by their photo-triggered events (i.e., crosslinking, degradation, and isomerization), which are inherently governed by photo-sensitive functionalities, including O-nitrobenzyl, coumarin, azobenzene, cinnamyl, and spiropyran. In addition, the properties and applications of those polypeptide nanomaterials will be highlighted as well. Finally, the current challenges and future directions of this subject will be evaluated.

Photoresponsive peptide and polypeptide systems 15*: Synthesis of photo-crosslinkable poly(amino acid)s by watery process and its application as a reinforcement for polyion complex fibers

The present article described the synthesis of the coumarin-containing polypeptides using the water-soluble active ester method and the reinforcement of the polyion complex (PIC) fibers by the photochemical cross-linking between the polypeptide-pendant coumaryloxyacetyl groups. Two kinds of cationic polypeptides, poly(α,L-lysine) (PLL) and poly(α,L-ornithine) (PLO) were treated with (4-hydroxyphenyl)dimethyl sulfonium methyl sulfate ester in water to incorporate the photoreactive coumaryloxyacetyl groups into the side chain amino groups of the PLL and PLO. The contents of the photoreactive groups in the produced coumarin-containing polypepides were controlled by the molar ratios of the amino groups to the active ester. The resulting coumarin-containing cationic polypeptides were spun into the PIC fibers with the anionic polysaccharide gellan in water. The tensile strengths of the coumarin-containing PIC fibers were superior to those of the intact PLL- and PLO-gellan PIC fibers. The mechanical strength of the coumarin-containing PIC fibers further increased upon light-irradiation. From these results, we concluded that the hydrophobic interactions and the covalent cross-linking due to the photochemical dimerization between the coumaryloxyacetyl groups significantly contributed to reinforcement of the PIC fibers. The present results afford a new methodology to the PIC reinforcement that was achieved by the polymer modification reaction in watery process.

Incorporation of a photochromic hinge in a rodlike polypeptide and its influence on dielectric and optical properties

AbstractA hinged, photoresponsive polypeptide (PAzP) was prepared and the effect of the photochromic hinge on the dielectric and photoisomerization behavior of the polymer in solution was probed. Polymerization of N‐carboxyanhydride of γ‐benzyl‐L‐glutamate was carried out with two different bifunctional photochromic amine initiators: di[(mercaptoethylamine)‐methylpropanamide]azobenzene (DMMPAB) and diaminoazobenzene (DAAB). Careful structural comparison of the polymers revealed that the basicity of the initiator plays a key role in determining the shape and structure of the polymer. Specifically, the use of a novel initiator DMMPAB prepared by the addition of flexible aliphatic amine substituents onto DAAB resulted in a hinged polymer (PAzP1), in which a single photochromic hinge was located within the polymer chain (Mw ∼ 36 kDa). In contrast, direct initiation with DAAB resulted in a polymer (PAzP2) in which the photochromic moiety was preferentially near the terminus of the polymer chain (Mw ∼ 21 kDa) and the polymer possessed a significant degree of asymmetry. Dielectric spectroscopy revealed that, in spite of a higher molecular weight, PAzP1 had a lower rotational relaxation time (2.72 μs) in solution than that of PAzP2 (4.41 μs). The residual dipole moment for the hinged PAzP1 was also smaller than that observed for PAzP2. The hinged polypeptide PAzP1 prepared from DMMPAB showed uniform photoisomerization between cis and trans states. However, the presence of flexible aliphatic amine substituents on DMMPAB caused the rate of isomerization of PAzP1 to be similar to the initiator DMMPAB. Optical characterization revealed that heterogeneity in the structure of PAzP2 was manifested as nonuniform rates of photoisomerization and thermal relaxation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2759–2773, 2001

Photoresponsive Polypeptides

Polypeptides containing azobenzene or spiropyran units attached to the macromolecules respond to light or dark conditions giving reversible variations of their structure. In this Account we provide a short overview of current research in the field and describe the most significant experimental examples of photoresponse effects. They include photoinduced random coil/alpha-helix transitions, helix-sense reversal, photostimulated aggregation/disaggregation processes, and photomechanical effects. These fascinating properties suggest that photoresponsive polypeptides may become suitable materials for designing sensors and devices that can be photomodulated. Findings also demonstrate that it is possible to synthesize model systems which respond to light similarly to naturally occurring photoreceptors.

光応答性合成ポリペプチドチャネルの構造と機能制御

Life phenomena such as signal transduction and chemical balance in neural systems, are determined by proper and exquisitely timed changes in ion channel mediated conductance and/or membrane potential. The fundamental structure of ion channels is a bundle arrangement of the amphiphilic domains of a channel protein situated in a biological membrane. Stimulation induced high-order structural changes in the bundle resulting in the regulation of ion permeability through the membrane. We prepared a photo-responsive amphiphilic polypeptide composed of two amphiphilic α-helical polypeptides, poly [(γ-methyl L-glutamate) -co- (L-glutamic acid)] jointed by an azobenzene molecule as our photo-responsive ion channel model. We investigated the photo-induced structural and functional changes of this photo-responsive polypeptide within a lipid membrane. In the dark, the polypeptide formed a transmembrane bundle within the membrane by self-association causing the bundle to act as an ion permeable path. Photo-irradiation induced bending of the polypeptide via a trans-cis photo-isomerization of the azobenzene moiety. The photo-induced structural changes in the polypeptide resulted in a destablization of the transmembrane bundle, and the subsequent blocking of the ion permeable path. This behavior arose from the photo-induced denaturation of the amphiphilic character of the polypeptide. As a result, photo-induced structural changes of the polypeptide were observed to regulate transmembrane ion transport.

Photoresponsive Polypeptides. Photochromic and Conformational Behavior of Spiropyran-Containing Poly(l-glutamate)s under Acid Conditions

High molecular weight poly(l-glutamic acid) was chemically modified with a spiropyran reagent to give polypeptides containing 35 and 85 mol % spiropyran units in the side chains. To investigate the...

Photoresponsive behavior of self-assembling systems by amphiphilic α-helix with azobenzene unit

Abstract A photoresponsive amphiphilic polypeptide composed of two amphiphilic α-helical polypeptides, poly [(γ-methyl l -glutamate)-co-( l -glutamic acid)], joined with an azobenzene moiety, was prepared via the monolayer reaction method. We investigated the photoinduced changes in the aggregate structure of the polypeptide in aqueous solution. The polypeptides were soluble in aqueous solution and associated with each other to form a globular aggregate ≈ 10 nm in diameter in the dark. The globular aggregate grew into a twisted ribbon-like structure which could be observed with an optical microscope. The trans -to- cis isomerization of the azobenzene unit in the main chain induced a bending of the polypeptide rod, which resulted in a dissociation of the aggregate. In this process, the degree of disaggregation was not linear to the irradiated light intensity, i.e., the photoinduced effect appeared over a certain value of the Sight intensity. Such on-off deformations of the supramolecular order may be due to a native character of self-organizing systems supported by weak but cooperative intermolecular interactions.

Photocontrol of Molecular Orientation of a Photoresponsive Amphiphilic α-Helix in a Lipid Monolayer

We prepared a photoresponsive polypeptide, Mn = 10 630, composed of two amphiphilic α-helical copolypeptides, poly[(γ-methyl l-glutamate)-co-(l-glutamic acid)], joined by an azobenzene (am.-MAzoM) as a molecular photoreceptor. Dipalmitoylphosphatidylcholine monolayers containing the am.-MAzoM were formed at the air−water interface. We investigated photoinduced changes in the structure of the polypeptide−lipid monolayer systems. The α-helical rod of am.-MAzoM was laid at the air−water interface when the monolayer was in a liquid state. While in the solid condensed monolayer, the polypeptide molecules arranged perpendicular to the membrane (the air−water interface) and formed a bundle by self-association. The bundle of am.-MAzoM could be observed as an intramembranous particle ca. 4 nm in diameter with atomic force microscopy. UV light irradiation induced the destabilization of the bundle structure in the monolayer. This behavior arose from the photoinduced denaturation of the amphiphilic character of the polypeptide owing to a bending of the polypeptide in the main chain by a cis−trans photoisomerization of the azobenzene moiety. After removal of the light, the am.-MAzoM in the solid condensed monolayer returned to the original bundle structure.

Photo-responsive behavior of a monolayer composed of an azobenzene containing polypeptide in the main chain

A photoresponsive polypeptide, two α-helical poly(γ-methyl L-glutamate)s joined with an azobenzene (MAzoM,Mn=11000), have been prepared. Monolayers of the polypeptide were formed at air-water interface and the photoresponsive behavior of the monolayer obtained was investigated. A trans to cis photo-isomerization of the azobenzene moiety in the main chain of MAzoM induced by UV light irradiation resulted in a bending structure formation in the main chain of the polypeptide via photo-induced changes in the geometry of the azobenzene chromophore. As a result, the limiting area per molecule of the MAzoM monolayer was decreased. Based on the degree of the decrease in the limiting area per molecule, it was estimated that the bending angle between the two α-helical rods of MAzoM molecule under UV light irradiation was ca. 140°. The photo-responsive behavior of the MAzoM monolayer was reversible and consisted along with the photo-isomerization of azobenzene moiety.

Photoinduced Structural and Functional Changes of an Azobenzene Containing Amphiphilic Sequential Polypeptide

We prepared a photoresponsive amphiphilic sequential polypeptide, M n = 10 630, composed of two amphiphilic α-helical copolypeptides, poly[(γ-methyl L-glutamate)-co-(L-glutamic acid)], jointed by an azobenzene as a model of photoreceptors. We investigated the photoinduced structural and functional changes of the photoresponsive polypeptide in an aqueous solution and a dipalmitoylphosphatidylcholine bilayer membrane system, respectively. In the dark, the photoresponsive amphiphilic sequential polypeptides formed a micelle in aqueous solution and a transmembrane bundle in the bilayer membrane, respectively. The transmembrane bundle in the membrane acted as an ion permeable path. UV light irradiation induced a bending of the polypeptide by a trans-cis photoisomerization of the azobenzene moiety. The photoinduced structural changes of the polypeptide resulted in a disaggregation of the micelle in aqueous solution and a destabilization of the transmembrane bundle, respectively. The behavior arose from a photoinduced denaturation of the amphiphilic character of the polypeptides. After removal of the light, the initial micellar aggregate in aqueous solution did not recover. However, the polypeptides in the membrane returned to the original transmembrane bundle structure. As a result, photoinduced reversible structural changes of the polypeptide in the bilayer membrane could regulate a transmembrane ion transport.

Photoresponsive polypeptides: Photochromism and conformation of poly (L‐glutamic acid) containing spiropyran units

AbstractSpirobenzopyran units were bound to the side chains of poly (L‐glutamic acid) and partially methylated poly(L‐glutamate)s. The modified polymers were found to exhibit “reverse photochromism” in hexafluoro‐2‐propanol (HFP), so the samples kept in the dark were characterized by an intense absorption band in the visible range of the spectrum, which was completely erased upon exposure to sunlight or irradiation at 500–550 nm.The CD spectra showed that the macromolecules adopted a random coil conformation in the dark, whereas the bleached solutions after exposure to light displayed the typical CD pattern of the α‐helix. The back reaction in the dark was accompanied by the progressive decrease of the helix content and recovery of the original disordered conformation. The photoinduced conformational changes resulted in large and reversible viscosity variations.When spiropyran side chains were converted to “spiropyran salts” of trifluoroacetic acid, the system was still photochromic, but the macromolecules were disordered both in the dark and light conditions. However, when appropriate amounts of methanol were added as a cosolvent to the HFP solutions, the system responded to light, giving reversible variations of the α‐helix content. Irradiation at appropriate solvent compositions allowed modulation of the extent of the photoresponse. © 1993 John Wiley & Sons, Inc.

Photoregulation of permeability across a membrane from a graft copolymer containing a photoresponsive polypeptide branch

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoregulation of permeability across a membrane from a graft copolymer containing a photoresponsive polypeptide branchMasato Aoyama, Jun Watanabe, and Shohei InoueCite this: J. Am. Chem. Soc. 1990, 112, 14, 5542–5545Publication Date (Print):July 1, 1990Publication History Published online1 May 2002Published inissue 1 July 1990https://doi.org/10.1021/ja00170a018RIGHTS & PERMISSIONSArticle Views231Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (490 KB) Get e-Alerts Get e-Alerts

Photocontrol of the Structure and Functions of a Polypeptide Membrane Composed of Poly(L-glutamic acid) Containing Pararosaniline Leucocyanide Groups in the Side Chains

A photo-responsive polypeptide membrane composed of poly(L-glutamic acid) (PGA) containing 38.3 mol% pararosaniline leucocyanide (rose(CN)) groups in the side chains was prepared. The ultraviolet (UV) light irradiation could produce cationic side chains along the polypeptide backbone resulting from a photodissociation of rose(CN) side chains in the membrane, which arises an electrostatic repulsive forces among the cationic side chains. This increased electrostatic repulsive force destabilized the α-helical structure of the rose(CN)-PGA in the membrane. As a result, the membrane functions of rose(CN)-PGA, such as membrane potential and transport properties, were strongly dependent on UV light irradiation, especially, the permeability of KCl through the rose(CN)-PGA membrane was much increased by a factor of 16 upon UV irradiation. The photoinduced changes of the membrane functions were reversible and consistent with the photoinduced conformational changes of rose(CN)-PGA membrane.

Photomodulation of polypeptide conformation by sunlight in spiropyran-containing poly(L-glutamic acid)

Photochromic vinyl polymers, such as polyacrylates containing spiropyran groups, were found to undergo photoinduced variations of their viscosity. Since the viscosity of a polymer system is in part a reflection of polymer conformation, the photoviscosity effects were generically attributed to photoinduced conformational changes of the macromolecules. From the point of view of conformational properties, photochromic polypeptides are much more attractive systems, since they can exist in definite ordered structures such as {alpha}-helix or {beta}-structures, and their conformational variations can be directly investigated by means of CD measurements. In addition, their structure is much more relevant to the proteic nature of biological photoreceptors. In this context the authors report the first preparation of a photoresponsive polypeptide containing spiropyran units in the side chains and clear CD evidence that the polypeptide can undergo large random coil {r equilibrium} {alpha}-helix conformational changes upon exposure to sunlight and dark conditions, alternately. Moreover, irradiation in solvent mixtures having appropriate compositions allows the extent of the photoresponse to be controlled.

Photocontrol of Polypeptide Membrane Functions by Photodissociation of Pararosaniline Side-Chain Groups

A photoresponsive polypeptide membrane composed of poly(L-glutamic acid) (PGA) with 15.5 mol% pararosaniline (rose) groups in the side chains (rose-PGA) were prepared. The rose side chains in the membrane exhibited photodissociation under ultraviolet (UV) light irradiation, yielded hydroxide ions, which resulted in the acceleration of acid dissociation of the neighboring L-glutamic acid moieties. This increase in the dissociation of L-glutamic acid moieties induced the conformational transitions of the rose-PGA membrane at adequate pHs. As a result, the membrane functions of the rose-PGA, such as transport properties and membrane potentials across the membrane, were strongly dependent on UV light irradiation. The photoinduced changes of the membrane functions of the rose-PGA were reversible and synchronized with the conformational responses of the membrane under UV light irradiation.

Permeability Changes of a Porous Membrane by an Adsorbed Photoresponsive Polypeptide

Photoresposive polypeptides, poly(L-glutamic acid)s containing azobenzene-4-sulfonic acid residues in the side chains (azo·S-X-PGA, X is the mol% of the azobenzene sulfonate residue), were adsorbed onto a porous support membrane and photoinduced permeation changes of the membrane obtained were studied. The maximum amount of adsorption, nmax (g g−1), of azo·S-PGA in the membrane was shown to decrease by increasing the azobenzene sulfonate groups, X, resulting from decrease in the content of the L-glutamic acid residues which interact with the adsorption sites on the pore wall through hydrogen bonds. It was estimated that the value of nmax of the azo·S-14.1-PGA adsorbed membrane used for the permeation measurements was 1.40×10−2 g of the polymer per g of the support membrane. The filtration coefficient of the azo·S-14.1-PGA adsorbed membrane largely decreased at the pH where α-helix to coil transition of the polymer occurred, indicating that permeation of the membrane was mainly determined by the conformation of the adsorbed azo·S-PGA on the pore wall. Moreover, it was observed that photoirradiation of the membrane at adequate pHS could induce rapid decrease in Lp of the membrane within a few minute. The photoresposive behavior of the membrane can be explained in terms of the photoinduced helix to coil transition of the azo·S-14.1-PGA in the membrane. The permeability of the membrane containing azo·S-46.3-PGA, which was in the random coil state at any given pH value in the aqueous solution, was independent on pH and photoirradiation.

Photocontrol of vesicular adhesion and functions by a photoresponsive polypeptide

Preparation d'un copolymere glutamate de γ-methyle/acide glutamique modifie par l'azobenzene incorporation dans une membrane de vesicules composees de chlorure de distearyldimethylammonium puis irradiation UV; il se produit un transfert du polypeptide de l'interieur de la membrane a la surface hydrophile