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
experimental part, 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.
Structure and mechanism of ORF36, an amino sugar oxidizing enzyme in everninomicin biosynthesis
Vey, Jessica L.,Al-Mestarihi, Ahmad,Hu, Yunfeng,Funk, Michael A.,Bachmann, Brian O.,Iverson
experimental part, p. 9306 - 9317 (2011/11/07)
Everninomicin is a highly modified octasaccharide that belongs to the orthosomycin family of antibiotics and possesses potent Gram-positive antibiotic activity, including broad-spectrum efficacy against multidrug resistant enterococci and Staphylococcus aureus. Among its distinctive structural features is a nitro sugar, l-evernitrose, analogues of which decorate a variety of natural products. Recently, we identified a nitrososynthase enzyme encoded by orf36 from Micromonospora carbonacea var. africana that mediates the flavin-dependent double oxidation of synthetically generated thymidine diphosphate (TDP)-l-epi-vancosamine to the corresponding nitroso sugar. Herein, we utilize a five-enzyme in vitro pathway both to verify that ORF36 catalyzes oxidation of biogenic TDP-l-epi-vancosamine and to determine whether ORF36 exhibits catalytic competence for any of its biosynthetic progenitors, which are candidate substrates for nitrososynthases in vivo. Progenitors solely undergo single-oxidation reactions and terminate in the hydroxylamine oxidation state. Performing the in vitro reactions in the presence of 18O2 establishes that molecular oxygen, rather than oxygen from water, is incorporated into ORF36-generated intermediates and products and identifies an off-pathway product that correlates with the oxidation product of a progenitor substrate. The 3.15 A resolution X-ray crystal structure of ORF36 reveals a tetrameric enzyme that shares a fold with acyl-CoA dehydrogenases and class D flavin-containing monooxygenases, including the nitrososynthase KijD3. However, ORF36 and KijD3 have unusually open active sites in comparison to these related enzymes. Taken together, these studies map substrate determinants and allow the proposal of a minimal monooxygenase mechanism for amino sugar oxidation by ORF36.
