Bacterial Rhodopsin: Evidence for a New Type of Phototrophy in the Sea

• DOI: 10.1126/science.289.5486.1902
• Publication Date: 2002-07-27T09:37:46Z
• Authors: Oded Béjà; L. Aravind; Eugene V. Koonin; Marcelino T. Suzuki; Andrew Hadd; Linh P. Nguyen; Stevan B. Jovanovich; Christian M. Gates; Robert A. Feldman; John L. Spudich; Elena N. Spudich; Edward F. DeLong
• Keywords: Bacterioplankton; Halobacterium; Proton Pump

Extremely halophilic archaea contain retinal-binding integral membrane proteins called bacteriorhodopsins that function as light-driven proton pumps. So far, capable of generating a chemiosmotic potential in response to light have been demonstrated only archaea. We describe here type rhodopsin derived from bacteria was discovered through genomic analyses naturally occuring marine bacterioplankton. The bacterial encoded the genome an uncultivated γ-proteobacterium and shared highest amino acid sequence similarity with archaeal rhodopsins. protein functionally expressed Escherichia coli bound retinal form active, pump. new exhibited photochemical reaction cycle intermediates kinetics characteristic proton-pumping Our results demonstrate archaeal-like rhodopsins are broadly distributed among different taxa, including members domain Bacteria . data also indicate previously unsuspected mode bacterially mediated energy generation may commonly occur oceanic surface waters worldwide.