• 청정기술
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• 제17권3호
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• pp.280-282
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• 2011

광에너지를 이용하여 바이오원료 및 바이오케미컬을 생산하려는 새로운 시도가 많은 관심을 받고 있다. 특히, 광합성기작을 이용한 다양한 바이오유래 물질을 생산하려는 연구가 진행되고 있다. 본 연구에서는 광합성기작을 갖고 있는 해양 미생물인 Salinibacter ruber의 세포막에서 retinal과 salinixanthin의 작용으로 광전자를 흡수하는 역할을 하는 잔토로돕신을 수성 이상계 계면 농축법을 이용하여 효율적으로 분리하였다. 분리된 잔토로돕신을 생물학적 세포막인 레시틴으로 리포좀을 생성하여 잔토로돕신의 광전자흡수 활성을 그대로 갖는 인위적인 잔토로돕신-레시틴 리포좀을 제작하였다.

• Journal of Microbiology and Biotechnology
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• 제30권5호
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• pp.633-641
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• 2020

Microbial rhodopsins are a superfamily of photoactive membrane proteins with the covalently bound retinal cofactor. Isomerization of the retinal chromophore upon absorption of a photon triggers conformational changes of the protein to function as ion pumps or sensors. After the discovery of proteorhodopsin in an uncultivated γ-proteobacterium, light-activated proton pumps have been widely detected among marine bacteria and, together with chlorophyll-based photosynthesis, are considered as an important axis responsible for primary production in the biosphere. Rhodopsins and related proteins show a high level of phylogenetic diversity; we focus on a specific class of bacterial rhodopsins containing the '3 omega motif.' This motif forms a stack of three non-consecutive aromatic amino acids that correlates with the B-C loop orientation and is shared among the phylogenetically close ion pumps such as the NDQ motif-containing sodium-pumping rhodopsin, the NTQ motif-containing chloride-pumping rhodopsin, and some proton-pumping rhodopsins including xanthorhodopsin. Here, we reviewed the recent research progress on these 'omega rhodopsins,' and speculated on their evolutionary origin of functional diversity.

• Rapid Communication in Photoscience
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• 제2권2호
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• pp.60-63
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• 2013

Rhodopsins belong to a family of membrane-embedded photoactive retinylidene proteins. One opsin gene was isolated from ${\beta}$-proteobacterium (IMCC9480) which had been collected at the North Pole. It is very similar to Xanthorhodopin (XR) of HTCC2181. In this study, we carried out basic characterization of the rhodopsin. It has ${\lambda}max$ of 536, 554, and 546 nm at pH 4.0, 7.0, and 10.0, respectively. Since the pKa of its proton acceptor is around 6.27, we measured its proton pumping activity and photocycling rate at pH 8.0. It has a typical proton acceptor (D99) and donor (E110) which mediate proton translocation from intracellular to extracellular region when deduced from the sequence alignments. On the basis of in vitro proton pumping activity, it was proposed to have fast photocycling rate with M and O intermediates, indicating that it is a typical ion-pumping rhodopsin. Since the XR has not yet been expressed in any other heterologous expression system, we tried to get much more information about the XR through the XR-homologue rhodopsin.