Omega Rhodopsins: A Versatile Class of Microbial Rhodopsins

Soon Kyeong Kwon, Sung Hoon Jun, Jihyun F. Kim

Research output: Contribution to journalReview articlepeer-review

2 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)633-641
Number of pages9
JournalJournal of microbiology and biotechnology
Issue number5
Publication statusPublished - 2020 May 28

Bibliographical note

Funding Information:
This work was financially supported by grants from the National Research (2020R1C1C1004778, NRF-2017R1C1B2009025, and NRF-2016R1E1A1A01943552).

Funding Information:
This work was financially supported by grants from the National Research Foundation of Korea (2020R1C1C1004778, NRF-2017R1C1B2009025, and NRF-2016R1E1A1A01943552).

Publisher Copyright:
Copyright© 2020 by The Korean Society for Microbiology and Biotechnology

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Applied Microbiology and Biotechnology


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