β-D-Glucose-1P as a Substrate of NDP-Glc Pyrophosphorylases of Two Actinobacteria

M.D. ASENCIÓN DIEZ; M.A. BALLICORA; S.A. GUERRERO; A.A. IGLESIAS

San Miguel de Tucumán, Argentina

Congreso; XLV Reunión Anual de SAIB; 2009

SAIB

EN-P01.â-D-GLUCOSE-1P AS A SUBSTRATE OF NDP-GLCPYROPHOSPHORYLASES OF TWO ACTINOBACTERIAAsención Diez MD1; Ballícora MA2; Guerrero SA1; Iglesias AA11IAL(UNL-CONICET), Santa Fe, Argentina; 2Dept. Chemistry,Loyola Uni v e r s i t y at C1hi cago, EE.UU. E-mai l :masencion@fbcb.unl.edu.arIt is well known that the á-anomer of glucose-1P (áGlc1P) is acommon metabolite in different cells. However, only a feworganisms were reported to use the ß-anomer (ßGlc1P) in theirmetabolisms. Maltose and trehalose phosphorylase, together withß-phosphoglucomutase from certain organisms are the onlyenzymes identified as metabolizing ßGlc1P. Although the presenceof ßGlc1P in both bacteria and algae was reported, informationabout the metabolic role of this intermediate is scarce. ßGlc1P canbe used as a precursor for cell wall material in Lactococcus lactisand also it could be a component of a surface glycan inEnterococcus faecalis. Our group is focused in the characterizationof several NDP-GlcPPases and we analyzed ßGlc1P as substrate ofthese enzymes. In our hands, certain ADP-GlcPPases and UDPGlcPPasesutilized this alternative substrate. Interestingly, theseenzymes belong to two actinobacteria: Mycobacteriumtuberculosis H37Rv and Streptomyces coelicolor A3(2). Themycobacterial ADP-GlcPPase used ßGlc1P with about 3-foldlower affinity than the á-anomer, to also reach a 3-fold lower V . maxAlso, the enzyme activity with the ß-anomer was not affected byallosteric regulators. Results suggest that after the promiscuity touse anomeric forms of Glc1P certain NDP-GlcPPases may bedifferentially involved in divergent metabolic routes ofcarbohydrates in specific organisms.