New insights into metabolic properties of marine bacteria encoding proteorhodopsins.
Proteorhodopsin phototrophy was recently discovered in oceanic surface waters. In an effort to characterize uncultured proteorhodopsin-exploiting bacteria, large-insert bacterial artificial chromosome (BAC) libraries from the Mediterranean Sea and Red Sea were analyzed. Fifty-five BACs carried diverse proteorhodopsin genes, and we confirmed the function of five. We calculate that proteorhodopsin-exploiting bacteria account for 13% of microorganisms in the photic zone. We further show that some proteorhodopsin-containing bacteria possess a retinal biosynthetic pathway and a reverse sulfite reductase operon, employed by prokaryotes oxidizing sulfur compounds. Thus, these novel phototrophs are an unexpectedly large and metabolically diverse component of the marine microbial surface water.
Sabehi
Gazalah
G
Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
Loy
Alexander
A
Jung
Kwang-Hwan
KH
Partha
Ranga
R
Spudich
John L
JL
Isaacson
Tal
T
Hirschberg
Joseph
J
Wagner
Michael
M
Béjà
Oded
O
D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics* / Q000502:physiology; D002338:Carotenoids / Q000096:biosynthesis / Q000235:genetics; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004926:Escherichia coli / Q000235:genetics; D015723:Gene Library; D019156:Indian Ocean; D008027:Light; D008522:Mediterranean Sea; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009876:Operon; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics; D010802:Phylogeny; D020560:Proteobacteria / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D012243:Rhodopsin / Q000145:classification / Q000235:genetics* / Q000502:physiology; D025604:Rhodopsins, Microbial; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D025604:Rhodopsins, Microbial; C413548:proteorhodopsin; D002338:Carotenoids; D012243:Rhodopsin; D050862:Oxidoreductases Acting on Sulfur Group Donors