Limits...
Ion-pumping microbial rhodopsins.

Kandori H - Front Mol Biosci (2015)

Bottom Line: Ion-transporting proteins can be found in microbial rhodopsins, such as light-gated channels and light-driven pumps, which are the main tools in optogenetics.On the other hand, different kinds of H(+) and Cl(-) pumps have been found in marine bacteria, such as proteorhodopsin (PR) and Fulvimarina pelagi rhodopsin (FR), respectively.In addition, a light-driven Na(+) pump was found, Krokinobacter eikastus rhodopsin 2 (KR2).

View Article: PubMed Central - PubMed

Affiliation: Department of Frontier Materials and OptoBioTechnology Research Center, Nagoya Institute of Technology Nagoya, Japan.

ABSTRACT
Rhodopsins are light-sensing proteins used in optogenetics. The word "rhodopsin" originates from the Greek words "rhodo" and "opsis," indicating rose and sight, respectively. Although the classical meaning of rhodopsin is the red-colored pigment in our eyes, the modern meaning of rhodopsin encompasses photoactive proteins containing a retinal chromophore in animals and microbes. Animal and microbial rhodopsins possess 11-cis and all-trans retinal, respectively, to capture light in seven transmembrane α-helices, and photoisomerizations into all-trans and 13-cis forms, respectively, initiate each function. Ion-transporting proteins can be found in microbial rhodopsins, such as light-gated channels and light-driven pumps, which are the main tools in optogenetics. Light-driven pumps, such as archaeal H(+) pump bacteriorhodopsin (BR) and Cl(-) pump halorhodopsin (HR), were discovered in the 1970s, and their mechanism has been extensively studied. On the other hand, different kinds of H(+) and Cl(-) pumps have been found in marine bacteria, such as proteorhodopsin (PR) and Fulvimarina pelagi rhodopsin (FR), respectively. In addition, a light-driven Na(+) pump was found, Krokinobacter eikastus rhodopsin 2 (KR2). These light-driven ion-pumping microbial rhodopsins are classified as DTD, TSA, DTE, NTQ, and NDQ rhodopsins for BR, HR, PR, FR, and KR2, respectively. Recent understanding of ion-pumping microbial rhodopsins is reviewed in this paper.

No MeSH data available.


Function of rhodopsins. Animal rhodopsins are G-protein coupled receptors, which are categorized as sensors activating a soluble transducer. On the other hand, microbial rhodopsins can act as pumps, channel, and light-sensors. Arrows indicate the direction of transport or flow of a signal. Purple and orange arrows represent energy conversion and signal transduction, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4585134&req=5

Figure 1: Function of rhodopsins. Animal rhodopsins are G-protein coupled receptors, which are categorized as sensors activating a soluble transducer. On the other hand, microbial rhodopsins can act as pumps, channel, and light-sensors. Arrows indicate the direction of transport or flow of a signal. Purple and orange arrows represent energy conversion and signal transduction, respectively.

Mentions: The word “rhodopsin” originates from the Greek words “rhodo” and “opsis,” which indicate rose and sight, respectively. Thus, the classical meaning of rhodopsin is the red-colored pigment in the retinal rods of eyes. The chromophore molecule to absorb light is retinal, which is the origin of red color. Then, similar colored retinal-binding proteins were found in microbes, largely expanding the definition of the word rhodopsin. The modern meaning of rhodopsin encompasses photoactive proteins containing a retinal chromophore in animals and microbes (Ernst et al., 2014; Kandori, 2015). Rhodopsins are now found in all domains of life and are classified into two groups, animal and microbial rhodopsins. While animal rhodopsins are exclusively photosensory receptors as a specialized subset of G-protein coupled receptors, microbial rhodopsins have various functions, including as photosensory receptors, a light-switch for gene expression, photoactivatable enzymes, light-driven ion pumps and light-gated ion channels (Figure 1) (Ernst et al., 2014).


Ion-pumping microbial rhodopsins.

Kandori H - Front Mol Biosci (2015)

Function of rhodopsins. Animal rhodopsins are G-protein coupled receptors, which are categorized as sensors activating a soluble transducer. On the other hand, microbial rhodopsins can act as pumps, channel, and light-sensors. Arrows indicate the direction of transport or flow of a signal. Purple and orange arrows represent energy conversion and signal transduction, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585134&req=5

Figure 1: Function of rhodopsins. Animal rhodopsins are G-protein coupled receptors, which are categorized as sensors activating a soluble transducer. On the other hand, microbial rhodopsins can act as pumps, channel, and light-sensors. Arrows indicate the direction of transport or flow of a signal. Purple and orange arrows represent energy conversion and signal transduction, respectively.
Mentions: The word “rhodopsin” originates from the Greek words “rhodo” and “opsis,” which indicate rose and sight, respectively. Thus, the classical meaning of rhodopsin is the red-colored pigment in the retinal rods of eyes. The chromophore molecule to absorb light is retinal, which is the origin of red color. Then, similar colored retinal-binding proteins were found in microbes, largely expanding the definition of the word rhodopsin. The modern meaning of rhodopsin encompasses photoactive proteins containing a retinal chromophore in animals and microbes (Ernst et al., 2014; Kandori, 2015). Rhodopsins are now found in all domains of life and are classified into two groups, animal and microbial rhodopsins. While animal rhodopsins are exclusively photosensory receptors as a specialized subset of G-protein coupled receptors, microbial rhodopsins have various functions, including as photosensory receptors, a light-switch for gene expression, photoactivatable enzymes, light-driven ion pumps and light-gated ion channels (Figure 1) (Ernst et al., 2014).

Bottom Line: Ion-transporting proteins can be found in microbial rhodopsins, such as light-gated channels and light-driven pumps, which are the main tools in optogenetics.On the other hand, different kinds of H(+) and Cl(-) pumps have been found in marine bacteria, such as proteorhodopsin (PR) and Fulvimarina pelagi rhodopsin (FR), respectively.In addition, a light-driven Na(+) pump was found, Krokinobacter eikastus rhodopsin 2 (KR2).

View Article: PubMed Central - PubMed

Affiliation: Department of Frontier Materials and OptoBioTechnology Research Center, Nagoya Institute of Technology Nagoya, Japan.

ABSTRACT
Rhodopsins are light-sensing proteins used in optogenetics. The word "rhodopsin" originates from the Greek words "rhodo" and "opsis," indicating rose and sight, respectively. Although the classical meaning of rhodopsin is the red-colored pigment in our eyes, the modern meaning of rhodopsin encompasses photoactive proteins containing a retinal chromophore in animals and microbes. Animal and microbial rhodopsins possess 11-cis and all-trans retinal, respectively, to capture light in seven transmembrane α-helices, and photoisomerizations into all-trans and 13-cis forms, respectively, initiate each function. Ion-transporting proteins can be found in microbial rhodopsins, such as light-gated channels and light-driven pumps, which are the main tools in optogenetics. Light-driven pumps, such as archaeal H(+) pump bacteriorhodopsin (BR) and Cl(-) pump halorhodopsin (HR), were discovered in the 1970s, and their mechanism has been extensively studied. On the other hand, different kinds of H(+) and Cl(-) pumps have been found in marine bacteria, such as proteorhodopsin (PR) and Fulvimarina pelagi rhodopsin (FR), respectively. In addition, a light-driven Na(+) pump was found, Krokinobacter eikastus rhodopsin 2 (KR2). These light-driven ion-pumping microbial rhodopsins are classified as DTD, TSA, DTE, NTQ, and NDQ rhodopsins for BR, HR, PR, FR, and KR2, respectively. Recent understanding of ion-pumping microbial rhodopsins is reviewed in this paper.

No MeSH data available.