Structural basis for phosphorylation and allosteric regulation of bacterial glycogen phosphorylase by histidine phosphocarrier protein
Year: 2026
Type: article
Abstract: Protein phosphorylation is a universal regulatory mechanism, controlling virtually all aspects of bacterial physiology and pathogenesis, yet histidine phosphorylation remains among the least understood. The histidine phosphocarrier protein HPr not only drives bacterial glucose transmembrane uptake through the phosphotransferase system (PTS), but also controls key enzymes for central carbon metabolism, including glycogen phosphorylase (GP). Here we report cryoEM structures of multimeric Escherichia coli EcGP and their complexes with EcHPr. The EM maps reveal an unanticipated density at H806 of EcGP, consistent with histidine phosphorylation within a histidine-rich pocket at the N-terminal domain. Enzymatic assays reveal that EcHPr transfers a phosphoryl group to the N1 position of a histidine residue in EcGP. Through an integrative structural, mutational and functional approach, we uncover the molecular basis of EcHPr- EcGP selectivity and define the allosteric mechanism by which EcHPr regulates EcGP. We establish histidine phosphorylation as a mechanism of GP regulation, expanding the traditional paradigm of glycogen metabolism control in bacteria. Glycogen serves as an intracellular energy storage polymer while some bacteria also produce structurally diverse extracellular α-glucans. Here, the authors establish the molecular basis of phosphorylation and allosteric regulation of glycogen phosphorylase by histidine phosphocarrier protein HPr.
Source: Nature Communications
Authors: Valerio Di Domenico, Jorick Franceus, Leonardo Mastrella, Emma De Beul, Adrià Alcaide-Jiménez, Francisco Paredes-Martínez, Juan Carlos Villegas-Ruiz, Elena Holden, Alejandro Delgado Rey, Cecilia D’Angelo, Javier O. Cifuente, Weston B. Struwe, Ricardo M. Biondi, Alberto Marina, Sean R. Connell, Justin L. P. Benesch, Patricia Casino, Christophe Colleoni, Tom Desmet, Marcelo E. Guerin
Institutions: Consejo Superior de Investigaciones Científicas, Institut de Biologia Molecular de Barcelona, Ghent University, Universitat de València, University of Oxford, Institute for Scientific and Technological Research, BioCruces Health research Institute, Hospital de Cruces, University of the Basque Country, Instituto Biofisika, Max Planck Society, Biomedicine Research Institute of Buenos Aires - CONICET - Partner Institute of the Max Planck Society, Instituto de Salud Carlos III, Instituto de Biomedicina de Valencia, Ikerbasque, Centre National de la Recherche Scientifique, Université de Lille, Unité de Glycobiologie Structurale et Fonctionnelle
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $6,990
OpenAlex ID: W7155990013