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A unique clade of light-driven proton-pumping rhodopsins evolved in the cyanobacterial lineage
- Source :
- Scientific Reports, Vol 10, Iss 1, Pp 1-10 (2020), Scientific Reports
- Publication Year :
- 2020
- Publisher :
- Springer Science and Business Media LLC, 2020.
-
Abstract
- Microbial rhodopsin is a photoreceptor protein found in various bacteria and archaea, and it is considered to be a light-utilization device unique to heterotrophs. Recent studies have shown that several cyanobacterial genomes also include genes that encode rhodopsins, indicating that these auxiliary light-utilizing proteins may have evolved within photoautotroph lineages. To explore this possibility, we performed a large-scale genomic survey to clarify the distribution of rhodopsin and its phylogeny. Our surveys revealed a novel rhodopsin clade, cyanorhodopsin (CyR), that is unique to cyanobacteria. Genomic analysis revealed that rhodopsin genes show a habitat-biased distribution in cyanobacterial taxa, and that the CyR clade is composed exclusively of non-marine cyanobacterial strains. Functional analysis using a heterologous expression system revealed that CyRs function as light-driven outward H+ pumps. Examination of the photochemical properties and crystal structure (2.65 Å resolution) of a representative CyR protein, N2098R from Calothrix sp. NIES-2098, revealed that the structure of the protein is very similar to that of other rhodopsins such as bacteriorhodopsin, but that its retinal configuration and spectroscopic characteristics (absorption maximum and photocycle) are distinct from those of bacteriorhodopsin. These results suggest that the CyR clade proteins evolved together with chlorophyll-based photosynthesis systems and may have been optimized for the cyanobacterial environment.
- Subjects :
- 0301 basic medicine
Cyanobacteria
genetic structures
Lineage (evolution)
lcsh:Medicine
Article
Microbial ecology
Evolution, Molecular
Membrane biophysics
03 medical and health sciences
Phylogenetics
Rhodopsins, Microbial
lcsh:Science
Bacterial genomics
Multidisciplinary
030102 biochemistry & molecular biology
biology
lcsh:R
Photoreceptor protein
Bacteriorhodopsin
Proton Pumps
biology.organism_classification
030104 developmental biology
Rhodopsin
Evolutionary biology
biology.protein
lcsh:Q
Function (biology)
Archaea
Subjects
Details
- ISSN :
- 20452322
- Volume :
- 10
- Database :
- OpenAIRE
- Journal :
- Scientific Reports
- Accession number :
- edsair.doi.dedup.....c09aa30e55851a5d3626ce903fb7e492