Discovery notes
Xenorhodopsins, an enigmatic new class of microbial rhodopsins horizontally transferred between archaea and bacteria
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* Corresponding author: Eric E Allen eallen@ucsd.edu
1 Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA
2 Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
Biology Direct 2011, 6:52 doi:10.1186/1745-6150-6-52
Published: 10 October 2011Abstract
Based on unique, coherent properties of phylogenetic analysis, key amino acid substitutions and structural modeling, we have identified a new class of unusual microbial rhodopsins related to the Anabaena sensory rhodopsin (ASR) protein, including multiple homologs not previously recognized. We propose the name xenorhodopsin for this class, reflecting a taxonomically diverse membership spanning five different Bacterial phyla as well as the Euryarchaeotal class Nanohaloarchaea. The patchy phylogenetic distribution of xenorhodopsin homologs is consistent with historical dissemination through horizontal gene transfer. Shared characteristics of xenorhodopsin-containing microbes include the absence of flagellar motility and isolation from high light habitats.
Reviewers: This article was reviewed by Dr. Michael Galperin and Dr. Rob Knight.