Re-routing glucosamine-1P fate towards alternative enzymatic steps in Rhodococcus jostii

CEREIJO AE; ASENCION DIEZ MD; IGLESIAS AA; ALVAREZ HM

Buenos Aires

Congreso; Joint Meeting of Bioscience Societies - LIII Argentine Society for Biochemical and Molecular Biology Research (SAIB) Annual meeting; 2017

RE-ROUTING GLUCOSAMINE-1P FATE TOWARDSALTERNATIVE ENZYMATIC STEPS IN RhodococcusjostiiAntonela E Cereijo (1), Matías Damián Asencion Diez (1),Héctor M Álvarez (2), Alberto A Iglesias (1)(1) Instituto de Agrobiotecnología del Litoral (CONICET-UNL). (2) Instituto de Biociencias de la Patagonia(CONICET-UNPSJB).The amino sugar glucosamine (GlcN), 2-amino-2-deoxy-D-glucose,is an essential component of glycosaminoglycans and glycoproteins.Together with N-acetylglucosamine (GlcNAc) are amongthe most prevalent sugars in the biosphere and a major componentin cell envelopes of fungi and bacteria. Consistent with the ubiquityof these sugars, pathways for their metabolism (including catabolicand anabolic processes) are conserved in bacteria. GlcN is biosynthesizedfrom fructose6-P and is further acetylated to GlcNAc.The balance between GlcN and GlcNAc is essential for bacterialgrowth and involves GlcN-1P as a mere intermediary. Curiously, werecently discovered that GlcN-1P is efficiently used as a substrateby enzymes related to glycogen metabolism in Rhodococcus jostii.ADP-glucose pyrophosphorylase (ADP-GlcPPase, EC 2.7.7.27) activatesGlc-1P to ADP-Glc which acts as glucosyl donor for glycogensynthase (GlgSase, EC 2.4.1.21). GlcN-1P is a substrate of ADP-GlcPPase(mainly after activation), which represents a unique featureamong this enzyme from different organisms. Also, the actinobacterialGlgSase uses ADP-Glc and Glc-1P to synthesize maltose-1Pas a key metabolite in these organisms. We found that a R. jostiiGlgSase accepts GlcN1P (but not other hexose-1P) to the sameextent that Glc-1P. The fact that the two enzymes catalyzing consecutivemetabolic steps in the classical GlgAC pathway are able toefficiently utilize GlcN-1P suggest a role for the amino sugar differentthan the routing towards GlcNAc synthesis in R.jostii. Even more,we found that one of the annotated UDP-GlcPPases (EC 2.7.7.9)reacts 10-fold faster with GlcN-1P than Glc-1P supports the aboveassertion. Results presented in this work revisit GlcN metabolismin this biotechnological relevant organism. In addition, they are animportant source to study the evolution of carbohydrate related enzymesand, most importantly, a source for in vitro synthesis of newcompounds.