AUTHOR=Bhayani Jaina , Iglesias Maria Josefina , Minen Romina I. , Cereijo Antonela E. , Ballicora Miguel A. , Iglesias Alberto A. , Asencion Diez Matias D. 

TITLE=Carbohydrate Metabolism in Bacteria: Alternative Specificities in ADP-Glucose Pyrophosphorylases Open Novel Metabolic Scenarios and Biotechnological Tools

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.867384

DOI=10.3389/fmicb.2022.867384

ISSN=1664-302X

ABSTRACT=<p>We explored the ability of ADP-glucose pyrophosphorylase (ADP-Glc PPase) from different bacteria to use glucosamine (GlcN) metabolites as a substrate or allosteric effectors. The enzyme from the actinobacteria <italic>Kocuria rhizophila</italic> exhibited marked and distinctive sensitivity to allosteric activation by GlcN-6P when producing ADP-Glc from glucose-1-phosphate (Glc-1P) and ATP. This behavior is also seen in the enzyme from <italic>Rhodococcus</italic> spp., the only one known so far to portray this activation. GlcN-6P had a more modest effect on the enzyme from other Actinobacteria (<italic>Streptomyces coelicolor</italic>), Firmicutes (<italic>Ruminococcus albus</italic>), and Proteobacteria (<italic>Agrobacterium tumefaciens</italic>) groups. In addition, we studied the catalytic capacity of ADP-Glc PPases from the different sources using GlcN-1P as a substrate when assayed in the presence of their respective allosteric activators. In all cases, the catalytic efficiency of Glc-1P was 1–2 orders of magnitude higher than GlcN-1P, except for the unregulated heterotetrameric protein (GlgC/GgD) from <italic>Geobacillus stearothermophilus</italic>. The Glc-1P substrate preference is explained using a model of ADP-Glc PPase from <italic>A. tumefaciens</italic> based on the crystallographic structure of the enzyme from potato tuber. The substrate-binding domain localizes near the N-terminal of an α-helix, which has a partial positive charge, thus favoring the interaction with a hydroxyl rather than a charged primary amine group. Results support the scenario where the ability of ADP-Glc PPases to use GlcN-1P as an alternative occurred during evolution despite the enzyme being selected to use Glc-1P and ATP for α-glucans synthesis. As an associated consequence in such a process, certain bacteria could have improved their ability to metabolize GlcN. The work also provides insights in designing molecular tools for producing oligo and polysaccharides with amino moieties.</p>