Structure of phosphorylated enzyme I, the phosphoenolpyruvate:sugar phosphotransferase system sugar translocation signal protein

Alexey Teplyakov, Kap Lim, Peng Peng Zhu, Geeta Kapadia, Celia C.H. Chen, Jennifer Schwartz, Andrew Howard, Prasad T. Reddy, Alan Peterkofsky, Osnat Herzberg

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

Bacterial transport of many sugars, coupled to their phosphorylation, is carried out by the phosphoenolpyruvate (PEP):sugar phosphotransferase system and involves five phosphoryl group transfer reactions. Sugar translocation initiates with the Mg2+-dependent phosphorylation of enzyme I (EI) by PEP. Crystals of Escherichia coli EI were obtained by mixing the protein with Mg2+ and PEP, followed by oxalate, an EI inhibitor. The crystal structure reveals a dimeric protein where each subunit comprises three domains: a domain that binds the partner PEP:sugar phosphotransferase system protein, HPr; a domain that carries the phosphorylated histidine residue, His-189; and a PEP-binding domain. The PEP-binding site is occupied by Mg2+ and oxalate, and the phosphorylated His-189 is in-line for phosphotransfer to/from the ligand. Thus, the structure represents an enzyme intermediate just after phosphotransfer from PEP and before a conformational transition that brings His-189∼P in proximity to the phosphoryl group acceptor, His-15 of HPr. A model of this conformational transition is proposed whereby swiveling around an α-helical linker disengages the His domain from the PEP-binding domain. Assuming that HPr binds to the HPr-binding domain as observed by NMR spectroscopy of an EI fragment, a rotation around two linker segments orients the His domain relative to the HPr-binding domain so that His-189∼P and His-15 are appropriately stationed for an in-line phosphotransfer reaction.

Original languageEnglish (US)
Pages (from-to)16218-16223
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number44
DOIs
StatePublished - Oct 31 2006

Keywords

  • Phosphorylation
  • Sugar transport
  • X-ray crystallography

ASJC Scopus subject areas

  • General

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