Publications

• Purification, enzymatic characterization, and inhibition of the Z-farnesyl diphosphate synthase from Mycobacterium tuberculosis.

  Schulbach M.C., Mahapatra S., Macchia M., Barontini S., Papi C., Minutolo F., Bertini S., Brennan P.J., Crick D.C.

  We have recently shown that open reading frame Rv1086 of the Mycobacterium tuberculosis H37Rv genome sequence encodes a unique isoprenyl diphosphate synthase. The product of this enzyme, omega,E,Z-farnesyl diphosphate, is an intermediate for the synthesis of decaprenyl phosphate, which has a centr ... >> More

  We have recently shown that open reading frame Rv1086 of the Mycobacterium tuberculosis H37Rv genome sequence encodes a unique isoprenyl diphosphate synthase. The product of this enzyme, omega,E,Z-farnesyl diphosphate, is an intermediate for the synthesis of decaprenyl phosphate, which has a central role in the biosynthesis of most features of the mycobacterial cell wall, including peptidoglycan, arabinan, linker unit galactan, and lipoarabinomannan. We have now purified Z-farnesyl diphosphate synthase to near homogeneity using a novel mycobacterial expression system. Z-Farnesyl diphosphate synthase catalyzed the addition of isopentenyl diphosphate to omega,E-geranyl diphosphate or omega,Z-neryl diphosphate yielding omega,E,Z-farnesyl diphosphate and omega,Z,Z-farnesyl diphosphate, respectively. The enzyme has an absolute requirement for a divalent cation, an optimal pH range of 7-8, and K(m) values of 124 micrometer for isopentenyl diphosphate, 38 micrometer for geranyl diphosphate, and 16 micrometer for neryl diphosphate. Inhibitors of the Z-farnesyl diphosphate synthase were designed and chemically synthesized as stable analogs of omega,E-geranyl diphosphate in which the labile diphosphate moiety was replaced with stable moieties. Studies with these compounds revealed that the active site of Z-farnesyl diphosphate synthase differs substantially from E-farnesyl diphosphate synthase from pig brain (Sus scrofa). << Less

  J. Biol. Chem. 276:11624-11630(2001) [PubMed] [EuropePMC]

• Cloning and functional analysis of novel short-chain cis-prenyltransferases.

  Ambo T., Noike M., Kurokawa H., Koyama T.

  cis-Prenyltransferase catalyzes the synthesis of Z,E-mixed prenyl diphosphates by sequential condensation of isopentenyl diphosphate with allylic diphosphate. cis-Prenyltransferases can be classified into three subgroups: short-, medium-, and long-chain cis-prenyltransferase, according to their pr ... >> More

  cis-Prenyltransferase catalyzes the synthesis of Z,E-mixed prenyl diphosphates by sequential condensation of isopentenyl diphosphate with allylic diphosphate. cis-Prenyltransferases can be classified into three subgroups: short-, medium-, and long-chain cis-prenyltransferase, according to their product chain lengths. cis-Farnesyl diphosphate synthase from Mycobacterium tuberculosis has been the only example as short-chain cis-prenyltransferase so far characterized. In this study, we cloned the novel short-chain cis-prenyltransferases from three different bacteria, and characterized their enzymatic activities to compare and elucidate a common feature of the short-chain cis-prenyltransferases. Furthermore, we identified a specific isoleucine that is conserved in short-chain cis-prenyltransferases and located in close proximity of the omega-end of the geranyl diphosphate. Several site-directed mutants with respect to the isoleucine residue synthesized longer prenyl chain products and showed broader allylic substrate specificity. These results suggested that the isoleucine plays an important role in the substrate specificity and chain length determination mechanism of cis-prenyltransferase. << Less

  Biochem. Biophys. Res. Commun. 375:536-540(2008) [PubMed] [EuropePMC]

• Polyprenyl phosphate biosynthesis in Mycobacterium tuberculosis and Mycobacterium smegmatis.

  Crick D.C., Schulbach M.C., Zink E.E., Macchia M., Barontini S., Besra G.S., Brennan P.J.

  Mycobacterium smegmatis has been shown to contain two forms of polyprenyl phosphate (Pol-P), while Mycobacterium tuberculosis contains only one. Utilizing subcellular fractions from M. smegmatis and M. tuberculosis, we show that Pol-P synthesis is different in these species. The specific activitie ... >> More

  Mycobacterium smegmatis has been shown to contain two forms of polyprenyl phosphate (Pol-P), while Mycobacterium tuberculosis contains only one. Utilizing subcellular fractions from M. smegmatis and M. tuberculosis, we show that Pol-P synthesis is different in these species. The specific activities of the prenyl diphosphate synthases in M. tuberculosis are 10-to 100-fold lower than those in M. smegmatis. In M. smegmatis decaprenyl diphosphate and heptaprenyl diphosphate were the main products synthesized in vitro, whereas in M. tuberculosis only decaprenyl diphosphate was synthesized. The data from both organisms suggest that geranyl diphosphate is the allylic substrate for two distinct prenyl diphosphate synthases, one located in the cell membrane that synthesizes omega,E,Z-farnesyl diphosphate and the other present in the cytosol that synthesizes omega,E,E,E-geranylgeranyl diphosphate. In M. smegmatis, the omega,E, Z-farnesyl diphosphate is utilized by a membrane-associated prenyl diphosphate synthase activity to generate decaprenyl diphosphate, and the omega,E,E,E-geranylgeranyl diphosphate is utilized by a membrane-associated activity for the synthesis of the heptaprenyl diphosphate. In M. tuberculosis, however, omega,E,E,E-geranylgeranyl diphosphate is not utilized for the synthesis of heptaprenyl diphosphate. Thus, the difference in the compositions of the Pol-P of M. smegmatis and M. tuberculosis can be attributed to distinct enzymatic differences between these two organisms. << Less

  J. Bacteriol. 182:5771-5778(2000) [PubMed] [EuropePMC]

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