Structure, function, and insights into the biosynthesis of a head-to-head hydrocarbon in Shewanella oneidensis strain MR-1.
A polyolefinic hydrocarbon was found in nonpolar extracts of Shewanella oneidensis MR-1 and identified as 3,6,9,12,15,19,22,25,28-hentriacontanonaene (compound I) by mass spectrometry, chemical modification, and nuclear magnetic resonance spectroscopy. Compound I was shown to be the product of a head-to-head fatty acid condensation biosynthetic pathway dependent on genes denoted as ole (for olefin biosynthesis). Four ole genes were present in S. oneidensis MR-1. Deletion of the entire oleABCD gene cluster led to the complete absence of nonpolar extractable products. Deletion of the oleC gene alone generated a strain that lacked compound I but produced a structurally analogous ketone. Complementation of the oleC gene eliminated formation of the ketone and restored the biosynthesis of compound I. A recombinant S. oneidensis strain containing oleA from Stenotrophomonas maltophilia strain R551-3 produced at least 17 related long-chain compounds in addition to compound I, 13 of which were identified as ketones. A potential role for OleA in head-to-head condensation was proposed. It was further proposed that long-chain polyunsaturated compounds aid in adapting cells to a rapid drop in temperature, based on three observations. In S. oneidensis wild-type cells, the cellular concentration of polyunsaturated compounds increased significantly with decreasing growth temperature. Second, the oleABCD deletion strain showed a significantly longer lag phase than the wild-type strain when shifted to a lower temperature. Lastly, compound I has been identified in a significant number of bacteria isolated from cold environments.
Sukovich
David J
DJ
Graduate Program in Microbiology, Immunology, and Cancer Biology, University of Minnesota, St. Paul, Minnesota 55108, USA.
Seffernick
Jennifer L
JL
Richman
Jack E
JE
Hunt
Kristopher A
KA
Gralnick
Jeffrey A
JA
Wackett
Lawrence P
LP
D000475:Alkenes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics*; D017353:Gene Deletion; D023061:Gene Order; D005816:Genetic Complementation Test; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008954:Models, Biological; D015394:Molecular Structure; D005810:Multigene Family; D011995:Recombination, Genetic; D020592:Shewanella / Q000235:genetics / Q000378:metabolism*; D020615:Stenotrophomonas maltophilia / Q000235:genetics
D000475:Alkenes; D001426:Bacterial Proteins