Revealing the Properties of ADP-glucose Pyrophosphorylase from Ruminococcus albus

CEREIJO, AE; ASENCIÓN DIEZ, MD; IGLESIAS, AA

Mar del Plata

Congreso; LI Reunión Anual de SAIB; 2015

SAIB

ADP-glucose pyrophosphorylase (ADPGlcPPase) from Firmicutes (low G+C Gram-positive bacteria) is enconded by two genes, glgC and glgD, leading to a heterotetrameric protein structure, unlike other prokaryotic ADPGlcPPases. The enzyme from different Firmicutes sub-groups presents dissimilar kinetic and regulatory properties, as shown in Bacillales and Lactobacillales groups. So far no details are known about the ADPGlcPPase from Clostridiales, a third group of Firmicutes. To further explore structure-function relationships of this enzyme from Firmicutes, we performed the molecular cloning of the glgC and glgD genes encoding the ADPGlcPPase from Ruminococcus albus. Results show that the recombinant R. albus GlgC subunit expressed in Escherichia coli is active. Conversely, theGlgD subunit was found inactive when expressed alone; although its co-expression with GlgC increase by 2-fold the activity. These results place the ADPGlcPPase from R. albus in between those from Bacillales and Lactobacillales, supporting the phylogenetic analysis that groups GlgC and GlgD subunits in distinctive clusters respect to the Firmicutes groups. The complete characterization of regulatory and structural properties of R. albus ADPGlcPPase is critical to establish evolutionary relationships of this enzyme in Firmicutes and other Gram-positive and Gram-negative prokaryotes.