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Updated: Jan 31, 2026

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria
Published on: September 16, 2013
Heliorhodopsins are absent in diderm (Gram-negative) bacteria: Some thoughts and possible implications for activity
José Flores-Uribe1, Gur Hevroni1, Rohit Ghai2
1Faculty of Biology, Technion - Israel Institute of Technology, Haifa, Israel.
Abstract:
Microbial heliorhodopsins are a new type of rhodopsins, currently believed to engage in light sensing, with an opposite membrane topology compared to type-1 and type-2 rhodopsins. We determined heliorhodopsins presence/absence is monoderms and diderms representatives from the Tara Oceans and freshwater metagenomes as well as metagenome assembled genome collections. Heliorhodopsins are absent in diderms, confirming our previous observations in cultured Proteobacteria. We do not rule out the possibility that heliorhodopsins serve as light sensors. However, this does not easily explain their absence from diderms. Based on these observations, we speculate on the putative role of heliorhodopsins in light-driven transport of amphiphilic molecules.
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