title: Molecular profiling of Mycobacterium tuberculosis identifies tuberculosinyl nucleoside products of the virulence-associated enzyme Rv3378c.
abstract: To identify lipids with roles in tuberculosis disease, we systematically compared the lipid content of virulent Mycobacterium tuberculosis with the attenuated vaccine strain Mycobacterium bovis bacillus Calmette-Guérin. Comparative lipidomics analysis identified more than 1,000 molecular differences, including a previously unknown, Mycobacterium tuberculosis-specific lipid that is composed of a diterpene unit linked to adenosine. We established the complete structure of the natural product as 1-tuberculosinyladenosine (1-TbAd) using mass spectrometry and NMR spectroscopy. A screen for 1-TbAd mutants, complementation studies, and gene transfer identified Rv3378c as necessary for 1-TbAd biosynthesis. Whereas Rv3378c was previously thought to function as a phosphatase, these studies establish its role as a tuberculosinyl transferase and suggest a revised biosynthetic pathway for the sequential action of Rv3377c-Rv3378c. In agreement with this model, recombinant Rv3378c protein produced 1-TbAd, and its crystal structure revealed a cis-prenyl transferase fold with hydrophobic residues for isoprenoid binding and a second binding pocket suitable for the nucleoside substrate. The dual-substrate pocket distinguishes Rv3378c from classical cis-prenyl transferases, providing a unique model for the prenylation of diverse metabolites. Terpene nucleosides are rare in nature, and 1-TbAd is known only in Mycobacterium tuberculosis. Thus, this intersection of nucleoside and terpene pathways likely arose late in the evolution of the Mycobacterium tuberculosis complex; 1-TbAd serves as an abundant chemical marker of Mycobacterium tuberculosis, and the extracellular export of this amphipathic molecule likely accounts for the known virulence-promoting effects of the Rv3378c enzyme.
authors: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
authors: Emilie
authors: E
authors: Layre
authors: Ho Jun
authors: HJ
authors: Lee
authors: David C
authors: DC
authors: Young
authors: Amanda Jezek
authors: AJ
authors: Martinot
authors: Jeffrey
authors: J
authors: Buter
authors: Adriaan J
authors: AJ
authors: Minnaard
authors: John W
authors: JW
authors: Annand
authors: Sarah M
authors: SM
authors: Fortune
authors: Barry B
authors: BB
authors: Snider
authors: Isamu
authors: I
authors: Matsunaga
authors: Eric J
authors: EJ
authors: Rubin
authors: Tom
authors: T
authors: Alber
authors: D Branch
authors: DB
authors: Moody
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D019281:Dimerization; D008055:Lipids / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D013058:Mass Spectrometry; D008958:Models, Molecular; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000472:pathogenicity*; D011487:Protein Conformation; D014774:Virulence
chemical_list: C587948:1-tuberculosinyladenosine; D001426:Bacterial Proteins; D008055:Lipids; D019883:Alkyl and Aryl Transferases; C587947:Rv3378c protein, Mycobacterium tuberculosis
keywords: TbAd; terpenyl transferase