Publications

• Menaquinone biosynthesis: formation of aminofutalosine requires a unique radical SAM enzyme.

  Mahanta N., Fedoseyenko D., Dairi T., Begley T.P.

  Menaquinone (MK, vitamin K2) is a lipid-soluble molecule that participates in the bacterial electron transport chain. In mammalian cells, MK functions as an essential vitamin for the activation of various proteins involved in blood clotting and bone metabolism. Recently, a new pathway for the bios ... >> More

  Menaquinone (MK, vitamin K2) is a lipid-soluble molecule that participates in the bacterial electron transport chain. In mammalian cells, MK functions as an essential vitamin for the activation of various proteins involved in blood clotting and bone metabolism. Recently, a new pathway for the biosynthesis of this cofactor was discovered in Streptomyces coelicolor A3(2) in which chorismate is converted to aminofutalosine in a reaction catalyzed by MqnA and an unidentified enzyme. Here, we reconstitute the biosynthesis of aminofutalosine and demonstrate that the missing enzyme (aminofutalosine synthase, MqnE) is a radical SAM enzyme that catalyzes the addition of the adenosyl radical to the double bond of 3-[(1-carboxyvinyl)oxy]benzoic acid. This is a new reaction type in the radical SAM superfamily. << Less

  J. Am. Chem. Soc. 135:15318-15321(2013) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Deamination of 6-aminodeoxyfutalosine in menaquinone biosynthesis by distantly related enzymes.

  Goble A.M., Toro R., Li X., Ornelas A., Fan H., Eswaramoorthy S., Patskovsky Y., Hillerich B., Seidel R., Sali A., Shoichet B.K., Almo S.C., Swaminathan S., Tanner M.E., Raushel F.M.

  Proteins of unknown function belonging to cog1816 and cog0402 were characterized. Sav2595 from Steptomyces avermitilis MA-4680, Acel0264 from Acidothermus cellulolyticus 11B, Nis0429 from Nitratiruptor sp. SB155-2 and Dr0824 from Deinococcus radiodurans R1 were cloned, purified, and their substrat ... >> More

  Proteins of unknown function belonging to cog1816 and cog0402 were characterized. Sav2595 from Steptomyces avermitilis MA-4680, Acel0264 from Acidothermus cellulolyticus 11B, Nis0429 from Nitratiruptor sp. SB155-2 and Dr0824 from Deinococcus radiodurans R1 were cloned, purified, and their substrate profiles determined. These enzymes were previously incorrectly annotated as adenosine deaminases or chlorohydrolases. It was shown here that these enzymes actually deaminate 6-aminodeoxyfutalosine. The deamination of 6-aminodeoxyfutalosine is part of an alternative menaquinone biosynthetic pathway that involves the formation of futalosine. 6-Aminodeoxyfutalosine is deaminated by these enzymes with catalytic efficiencies greater than 10(5) M(-1) s(-1), Km values of 0.9-6.0 μM, and kcat values of 1.2-8.6 s(-1). Adenosine, 2'-deoxyadenosine, thiomethyladenosine, and S-adenosylhomocysteine are deaminated at least an order of magnitude slower than 6-aminodeoxyfutalosine. The crystal structure of Nis0429 was determined and the substrate, 6-aminodeoxyfutalosine, was positioned in the active site on the basis of the presence of adventitiously bound benzoic acid. In this model, Ser-145 interacts with the carboxylate moiety of the substrate. The structure of Dr0824 was also determined, but a collapsed active site pocket prevented docking of substrates. A computational model of Sav2595 was built on the basis of the crystal structure of adenosine deaminase and substrates were docked. The model predicted a conserved arginine after β-strand 1 to be partially responsible for the substrate specificity of Sav2595. << Less

  Biochemistry 52:6525-6536(2013) [PubMed] [EuropePMC]

• Diversity of the early step of the futalosine pathway.

  Arakawa C., Kuratsu M., Furihata K., Hiratsuka T., Itoh N., Seto H., Dairi T.

  We recently demonstrated that the futalosine pathway was operating in some bacteria for the biosynthesis of menaquinone and that futalosine was converted into dehypoxanthinyl futalosine (DHFL) by an MqnB of Thermus thermophilus. In this study, we found that aminodeoxyfutalosine, which has adenine ... >> More

  We recently demonstrated that the futalosine pathway was operating in some bacteria for the biosynthesis of menaquinone and that futalosine was converted into dehypoxanthinyl futalosine (DHFL) by an MqnB of Thermus thermophilus. In this study, we found that aminodeoxyfutalosine, which has adenine instead of hypoxanthine in futalosine, was directly converted into DHFL by an MqnB of Helicobacter pylori. Therefore, this step is potentially an attractive target for the development of specific anti-H. pylori drugs. << Less

  Antimicrob. Agents Chemother. 55:913-916(2011) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.