16752-71-9Relevant articles and documents
Investigation of the enzymes required for the biosynthesis of an unusual formylated sugar in the emerging human pathogen Helicobacter canadensis
Heisdorf, Colton J.,Griffiths, William A.,Thoden, James B.,Holden, Hazel M.
, p. 2144 - 2160 (2021/09/02)
It is now well established that the Gram-negative bacterium, Helicobacter pylori, causes gastritis in humans. In recent years, it has become apparent that the so-called non-pylori Helicobacters, normally infecting pigs, cats, and dogs, may also be involved in human pathology via zoonotic transmission. Indeed, more than 30 species of non-pylori Helicobacters have been identified thus far. One such organism is Helicobacter canadensis, an emerging pathogen whose genome sequence was published in 2009. Given our long-standing interest in the biosynthesis of N-formylated sugars found in the O-antigens of some Gram-negative bacteria, we were curious as to whether H. canadensis produces such unusual carbohydrates. Here, we demonstrate using both biochemical and structural techniques that the proteins encoded by the HCAN_0198, HCAN_0204, and HCAN_0200 genes in H. canadensis, correspond to a 3,4-ketoisomerase, a pyridoxal 5′-phosphate aminotransferase, and an N-formyltransferase, respectively. For this investigation, five high-resolution X-ray structures were determined and the kinetic parameters for the isomerase and the N-formyltransferase were measured. Based on these data, we suggest that the unusual sugar, 3-formamido-3,6-dideoxy-d-glucose, will most likely be found in the O-antigen of H. canadensis. Whether N-formylated sugars found in the O-antigen contribute to virulence is presently unclear, but it is intriguing that they have been observed in such pathogens as Francisella tularensis, Mycobacterium tuberculosis, and Brucella melitensis.
Characterization of the TDP-d-ravidosamine biosynthetic pathway: One-pot enzymatic synthesis of TDP-d-ravidosamine from thymidine-5-phosphate and glucose-1-phosphate
Kharel, Madan K.,Lian, Hui,Rohr, Juergen
, p. 1799 - 1808 (2011/05/03)
Ravidomycin V and related compounds, e.g., FE35A-B, exhibit potent anticancer activities against various cancer cell lines in the presence of visible light. The amino sugar moieties (d-ravidosamine and its analogues, respectively) in these molecules contribute to the higher potencies of ravidomycin and analogues when compared to closely related compounds with neutral or branched sugars. Within the ravidomycin V biosynthetic gene cluster, five putative genes encoding NDP-d-ravidosamine biosynthetic enzymes were identified. Through the activities of the isolated enzymes in vitro, it is demonstrated that ravD, ravE, ravIM, ravAMT and ravNMT encode TDP-d-glucose synthase, TDP-4-keto-6-deoxy-d-glucose-4,6-dehydratase, TDP-4-keto-6-deoxy-d- glucose-3,4-ketoisomerase, TDP-3-keto-6-deoxy-d-galactose-3-aminotransferase, and TDP-3-amino-3,6-dideoxy-d-galactose-N,N-dimethyl-transferase, respectively. A protocol for a one-pot enzymatic synthesis of TDP-d-ravidosamine has been developed. The results presented here now set the stage to produce TDP-d-ravidosamine routinely for glycosylation studies.
Stoichiometry of the redox neutral deamination and oxidative dehydrogenation reactions catalyzed by the radical SAM enzyme desll
Ruszczycky, Mark W.,Choi, Sei-Hyun,Liu, Hung-Wen
experimental part, p. 2359 - 2369 (2010/05/01)
Desll from Streptomyces venezuelae is a radical SAM (S-adenosyl-L- methionine) enzyme that catalyzes the deamination of TDP-4-amino-4,6-dideoxy-D- glucose to form TDP-3-keto-4,6-dideoxy-D-glucose in the biosynthesis of TDP-D-desosamine. Desll also catalyzes the dehydrogenation of the nonphysiological substrate TDP-D-quinovose to TDP-3-keto-6-deoxy-D-glucose. These properties prompted an investigation of how Desll handles SAM in the redox neutral deamination versus the oxidative dehydrogenation reactions. This work was facilitated by the development of an enzymatic synthesis of TDP-4-amino-4,6-dideoxy-Dglucose that couples a transamination equilibrium to the thermodynamically favorable oxidation of formate. In this study, Desll is found to consume SAM versus TDP-sugar with stoichiometries of 0.96 ± 0.05 and 1.01 ± 0.05 in the deamination and dehydrogenation reactions, respectively, using Na2S2O4 as the reductant. Importantly, no significant change in stoichiometry is observed when the flavodoxin/flavodoxin NADP+ oxidoreductase/NADPH reducing system is used in place of Na2S2O4. Moreover, there is no evidence of an uncoupled or abortive process in the deamination reaction, as indicated by the observation that dehydrogenation can take place in the absence of an external source of reductant whereas deamination cannot. Mechanistic and biochemical implications of these results are discussed.
