A paralog of a bacteriochlorophyll biosynthesis enzyme catalyzes the formation of 1,2-dihydrocarotenoids in green sulfur bacteria
| Autor: | Daniel P. Canniffe, Jennifer L. Thweatt, Donald A. Bryant, Aline Gomez Maqueo Chew, C. Neil Hunter |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Mutant Flavoprotein Rhodobacter sphaeroides Reductase Chlorobium medicine.disease_cause Biochemistry Microbiology Chlorobi 03 medical and health sciences Blastochloris viridis Bacterial Proteins energy metabolism medicine Molecular Biology Carotenoid Bacteriochlorophylls chemistry.chemical_classification photosynthesis biology Chlorobaculum tepidum Cell Biology biology.organism_classification Carotenoids carotenoid green sulfur bacterium Biosynthetic Pathways 030104 developmental biology chemistry Green sulfur bacteria biology.protein bacterial genetics Oxidoreductases Bacteria Genome Bacterial photosynthetic pigment |
| Zdroj: | The Journal of Biological Chemistry Journal of Biological Chemistry JOURNAL OF BIOLOGICAL CHEMISTRY |
| ISSN: | 1083-351X 0021-9258 |
| Popis: | Chlorobaculum tepidum, a green sulfur bacterium, utilizes chlorobactene as its major carotenoid, and this organism also accumulates a reduced form of this monocyclic pigment, 1′,2′-dihydrochlorobactene. The protein catalyzing this reduction is the last unidentified enzyme in the biosynthetic pathways for all of the green sulfur bacterial pigments used for photosynthesis. The genome of C. tepidum contains two paralogous genes encoding members of the FixC family of flavoproteins: bchP, which has been shown to encode an enzyme of bacteriochlorophyll biosynthesis; and bchO, for which a function has not been assigned. Here we demonstrate that a bchO mutant is unable to synthesize 1′,2′-dihydrochlorobactene, and when bchO is heterologously expressed in a neurosporene-producing mutant of the purple bacterium, Rhodobacter sphaeroides, the encoded protein is able to catalyze the formation of 1,2-dihydroneurosporene, the major carotenoid of the only other organism reported to synthesize 1,2-dihydrocarotenoids, Blastochloris viridis. Identification of this enzyme completes the pathways for the synthesis of photosynthetic pigments in Chlorobiaceae, and accordingly and consistent with its role in carotenoid biosynthesis, we propose to rename the gene cruI. Notably, the absence of cruI in B. viridis indicates that a second 1,2-carotenoid reductase, which is structurally unrelated to CruI (BchO), must exist in nature. The evolution of this carotenoid reductase in green sulfur bacteria is discussed herein. |
| Databáze: | OpenAIRE |
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