bioRxiv preprint doi: https://doi.org/10.1101/367102; this version posted July 11, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 acI Actinobacteria Assemble a Functional Actinorhodopsin with 2 Natively-synthesized Retinal 3 4 Running Title: (54 characters and spaces) Actinorhodopsin and Carotenoid Synthesis in acI 5 6 Jeffrey R. Dwulit-Smitha,b, Joshua J. Hamiltona, David M. Stevensona, Shaomei Hea,c, Ben O. 7 Oysermand, Francisco Moya-Floresd, Daniel Amador-Nogueza, Katherine D. McMahona,d, Katrina T. 8 Foresta,b# 9 10 aDepartment of Bacteriology; bProgram in Biophysics; cDepartment of Geoscience, and dDepartment of Civil 11 and Environmental Engineering, University of Wisconsin-Madison, Madison, WI, USA. 12 # Address correspondence to Katrina T. Forest, 1550 Linden Drive, Madison, WI 53706, tel. 608 265-3566, 13 email
[email protected]. 14 15 KEYWORDS 16 Freshwater, photoheterotrophy, opsin, rhodopsin, xanthorhodopsin, proton pump, carotenoid, blh 17 bioRxiv preprint doi: https://doi.org/10.1101/367102; this version posted July 11, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Dwulit-Smith et al. Actinorhodopsin and Carotenoid Synthesis in acI 18 ABSTRACT 19 Freshwater lakes harbor complex microbial communities, but these ecosystems are often dominated by acI 20 Actinobacteria from three clades (acI-A, acI-B, acI-C).