Glucosamine-P and rhodococcal ADP-glucose pyrophosphorylases: A hint to (re)discover (actino)bacterial amino sugar metabolism

Glycogen was described as a temporal storage molecule in rhodococci, interconnecting lipids and carbon availability. The Rhodococcus jostii ADP-glucose pyrophosphorylase (ADP-GlcPPase) kinetic and regulatory properties support this role. Curiously, the enzyme uses glucosamine-1P as alternative substrate. Herein, we report the in-depth study of glucosamine-1P activity and its regulation in two rhodocoocal ADP-GlcPPases, finding that glucosamine-6P (representing a metabolic carbon/nitrogen node) is a critical activator, then reinforcing the role of glycogen as an ?intermediary metabolite? in rhodococci. Glucosamine-1P activity in rhodococcal ADP-GlcPPases responds to activation by metabolites improving their catalytic performance, strongly suggesting its metabolic feasibility. This work supports a scenario for new molecules/metabolites discovery and hypothesizes on evolutionary mechanisms underlying enzyme promiscuity opening novel metabolic features in (actino)bacteria.Fil: Cereijo, Antonela Estefanía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Alvarez, Hector Manuel. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Iglesias, Alberto Alvaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; ArgentinaFil: Asención Diez, Matías Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentin