Opsin vs opsin: New materials for biotechnological applications

Alfinito, Eleonora; Reggiani, L.

doi:10.1063/1.4892445

Cited by 20 publications

(31 citation statements)

References 30 publications

(80 reference statements)

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“…The charge transfer through the protein was attributed to a tunneling mechanism [10,13,24,25]. In particular, the presence of a current (in dark) well above possible leakage components, and of a photocurrent (in light) supports the hypothesis of a mechanism of charge transfer intrinsically dependent on the protein tertiary structure [24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 94%

“…To account for the super-linear behaviour of current at increasing voltages, a tunneling mechanism of charge transfer is included. In doing so, a stochastic approach within a Monte Carlo scheme [24,25,27,[29][30][31][32] is used. In particular, following the Simmons model [38], a mechanism containing two possible tunneling processes, a direct tunneling (DT) at low bias, and a Fowler-Nordheim tunneling (FN) at high bias, is introduced.…”

Section: Theoretical Modelmentioning

confidence: 99%

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Mechanisms responsible for the photocurrent in bacteriorhodopsin

Alfinito

Reggiani

2015

Phys. Rev. E

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Recently, there has been growing interest in the electrical properties of bacteriorhodopsin (bR), a protein belonging to the transmembrane protein family. Several experiments pointed out the role of green light in enhancing the current flow in nanolayers of bR, thus confirming potential applications of this protein in the field of optoelectronics. By contrast, the mechanisms underlying the charge transfer and the associated photocurrent are still far from being understood at a microscopic level. To take into account the structure-dependent nature of the current, in a previous set of papers we suggested a mechanism of sequential tunneling among neighboring amino acids. As a matter of fact, when irradiated with green light, bR undergoes a conformational change at a molecular level. Thus, the role played by the protein tertiary-structure in modeling the charge transfer cannot be neglected. The aim of this paper is to go beyond previous models, in the framework of a new branch of electronics we call proteotronics, which exploits the ability of using proteins as reliable, well-understood materials for the development of novel bioelectronic devices. In particular, the present approach assumes that the conformational change is not the unique transformation the protein undergoes when irradiated by light. Instead, the light can also promote an increase of the protein state free energy that, in turn, should modify its internal degree of connectivity. This phenomenon is here described by the change of the value of an interaction radius associated with the physical interactions among amino acids. The implemented model enables us to achieve a better agreement between theory and experiments in the region of a low applied bias by preserving the level of agreement at high values of applied bias. Furthermore, results provide new insights on the mechanisms responsible for bR photoresponse.

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Section: Introductionmentioning

confidence: 94%

Section: Theoretical Modelmentioning

confidence: 99%

Mechanisms responsible for the photocurrent in bacteriorhodopsin

Alfinito

Reggiani

2015

Phys. Rev. E

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“…With an analogous procedure the rat OR I7, whose 3D structure consists of 327 amino acids [20], is compared with the cube7, the corresponding regular structure that consists of 7 nodes for edge, making a total of 343 nodes with gen=5,5Å. In both these cases, the value of the interaction radius, R C , has been chosen of 6Å as reported in previous papers [27,28]. The same is done for BR, whose 3D structure consists of 348 amino acids, and the comparison is carried out with the cube7.…”

Section: Methodsmentioning

confidence: 99%

“…A cartoon of cube3 with 3 nodes for edge, and an α-helix with the same number of amino acids (27) is shown in Fig. 1.…”

Section: Methodsmentioning

confidence: 99%

Current-voltage characteristics of seven-helix proteins from a cubic array of amino acids

Alfinito

Reggiani

2016

Phys. Rev. E

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The electrical properties of a set of seven-helix transmembrane proteins, whose space arrangement (3d structure) is known, are investigated by using regular arrays of the amino acids. These structures, specifically cubes, have topological features similar to those shown by the chosen proteins. The theoretical results show a good agreement between the predicted current-voltage characteristics obtained from a cubic array and those obtained from a detailed 3D structure. The agreement is confirmed by available experiments on bacteriorhodopsin. Furthermore, all the analyzed proteins are found to share the same critical behaviour of the voltage-dependent conductance and of its variance. In particular, the cubic arrangement evidences a short plateau of the excess conductance and its variance at high voltages. The results of the present investigation show the possibility to predict the I-V characteristics of multiple-protein sample even in the absence of a detailed knowledge of their 3D structure.

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“…Rhodopsin is a G protein-coupled receptor (GPCR) that absorbs light quantum thus initiating of enzymatic cascade of phototransduction in photoreceptors [3]. It consists of apoprotein opsin and 11-cis-retinal chromophore bound by Shiff-base linkage [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Novel Rhodopsin Gene from Octopus vulgaris for Optobioelectronics Materials

Zhgun¹,

Avdanina²,

Eldarov³

et al. 2015

NanoWorld J

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The unique photochromic retinal protein from rhabdomeric octopus membranes -octopus rhodopsin (OctR) has emerged as promising material for biomolecular photonic applications due to its unique properties and advantages. Here we report isolation of the novel full length octR gene from retina cDNA of Octopus vulgaris eyes and its sequence comparison with rhodopsins of other cephalopods and vertebrates. The isolated gene can be used to develop various expression systems for production of recombinant OctR for structural studies and novel optobioelectronic applications. The alignment of amino acid (a.a.) sequence with different opsins revealed similarity to cephalopoda rhodopsins (Rho) and to human melanopsin from intrinsically photosensitive retinal ganglion cells. The alingment of OctR a.a. sequence with mammalian and cephalopoda Rho with known 3D structures revealed promising substitutions V2C and W292C for developing stable and functionally active recombinant OctR after heterologous expression.

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Opsin vs opsin: New materials for biotechnological applications

Cited by 20 publications

References 30 publications

Mechanisms responsible for the photocurrent in bacteriorhodopsin

Mechanisms responsible for the photocurrent in bacteriorhodopsin

Current-voltage characteristics of seven-helix proteins from a cubic array of amino acids

A Novel Rhodopsin Gene from Octopus vulgaris for Optobioelectronics Materials

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