Structural and mechanistic diversity of glycogen phosphorylases from gut bacteria.

ABSTRACT: Glycogen phosphorylase (GP) plays a central role in glycogen metabolism. While the structure and regulation of mammalian GPs have been extensively studied, the corresponding mechanisms in gut bacterial GPs remain poorly understood. Here, we investigate GPs from Escherichia coli (EcGP), Segatella copri (ScGP), and Dorea longicatena (DlGP), which represent three phylogenetic clades of GPs, using enzymatic assays, cryo-electron microscopy (cryo-EM), and X-ray crystallography. We find that ScGP forms a unique pentamer that undergoes adenosine monophosphate (AMP)-dependent assembly into a dimer-of-pentamer, which inhibits activity by restricting substrate access to the catalytic site. EcGP exists in equilibrium among monomers, dimer

SUBMITTER: Shobu K 

PROVIDER: S-EPMC12912991 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature