- Synthesis of a non-natural glucose-2-phosphate ester able to dupe the acc system of: Agrobacterium fabrum
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The first non-natural derivative of the rare d-glucose-2-phosphate (G2P), namely glucose-2-(O-lactic acid phosphate) (G2LP), has been synthesized. When used as sole carbon source, G2LP enables bacterial growth of the plant pathogenic strain Agrobacterium fabrum C58 (formerly referred to as Agrobacterium tumefaciens). X-ray crystallography and affinity measurements investigations reveal that G2LP binds the periplasmic binding protein (PBP) AccA similarly to the natural compounds and with the same affinity. Moreover, enzymatic assays show that it is able to serve as substrate of the phosphodiesterase AccF. The properties found for G2LP demonstrate that the very unusual glucose-2-phosphoryl residue, present in G2LP, can be used as structural feature for designing non-natural systems fully compatible with the Acc cascade of A. fabrum.
- Li, Si-Zhe,Vigouroux, Armelle,Ahmar, Mohammed,El Sahili, Abbas,Soulère, Laurent,Sago, La?la,Cornu, David,Moréra, Solange,Queneau, Yves
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- Esters of Glucose-2-Phosphate: Occurrence and Chemistry
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Phosphodiesters of glucose-2-phosphate (G2P) are found only in few natural compounds such as agrocinopine D and agrocin 84. Agrocinopine D is a G2P phosphodiester produced by plants infected by Agrobacterium fabrum C58 and recognized by the bacterial periplasmic binding protein AccA for being transported into the bacteria before cleavage by the phosphodiesterase AccF, releasing G2P, which promotes virulence by binding the repressor protein AccR. The G2P amide agrocin 84 is a natural antibiotic produced by the non-pathogenic Agrobacterium radiobacter K84 strain used as a biocontrol agent by competing with Agrobacterium fabrum C58. G2P esters are also found in irregular glycogen structures. The rare glucopyranosyl-2-phophoryl moiety found in agrocin 84 is the key structural signature enabling its action as a natural antibiotic. Likewise, G2P and G2P esters can also dupe the Agrobacterium agrocinopine catabolism cascade. Such observations illustrate the importance of G2P esters on which we have recently focused our interest. After a brief review of the reported phosphorylation coupling methods and the choice of carbohydrate building blocks used in G2P chemistry, a flexible access to glucose-2-phosphate esters using the phosphoramidite route is proposed.
- Ahmar, Mohammed,Li, Si-Zhe,Queneau, Yves,Soulère, Laurent,Zhang, Qiang
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- The effectivity of 1H-triazoles and -tetrazoles as activators in acid-catalyzed phosphoramidite alcoholysis
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The efficiency of 5-nitro-1,2,4-1H-triazole (3), 5-(methylthio)-1H-tetrazole (4), and 5-(4-nitrophenyl)-1H-tetrazole (5) as activators in phosphoramidite alcoholysis has been studied relative to 1H-tetrazole (6). Reactions of these azoles with diisopropyl (diisopropylamido)phosphite (1a) were followed in THF, and the rates were found to increase with increasing acidity of the azoles. The Bronsted a value of 0.7 determined for this dependence is in agreement with data published earlier.
- Nurminen, Erkki J.,Mattinen, Jorma K.,Loennberg, Harri
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p. 2005 - 2008
(2007/10/03)
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- Acridine-Labeled Primers as Tools for the Study of Nonenzymatic RNA Oligomerization
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Short, dye-labeled oligonucleotides have been used as primers in template-controlled polymerization reactions of RNA. The synthesis of appropriate acridine derivatives and their attachment to nucleic acids is described. In the nonenzymatic oligomerization of 2-methyl-1H-imidazole-activated guanosine 5′-monophosphate, two observations deserve special notice: 1) reaction rates are almost unchanged by variations of the Na+ concentration; 2) the conformational type of the primer-template duplex (A vs. B) has considerable influence on the rates and yields of RNA oligomerization. When the incorporation of cytidine was studied in the presence of 1M Na+ or K+, the process was almost inhibited by quadruplex formation of the oligo-dG template. However, if these cations were omitted, an efficient primer extension could be observed using template concentrations as high as 100 μM. The chances for nonenzymatic self-replication of RNA thus might be distinctly better than previously assumed.
- Kurz, Markus,Goebel, Karin,Hartel, Christian,Goebel, Michael W.
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p. 1156 - 1180
(2007/10/03)
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