Structure of phosphorylated enzyme I, the phosphoenolpyruvate:sugar phosphotransferase system sugar translocation signal protein.
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 Mg(2+)-dependent phosphorylation of enzyme I (EI) by PEP. Crystals of Escherichia coli EI were obtained by mixing the protein with Mg(2+) 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 Mg(2+) 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 approximately P in proximity to the phosphoryl group acceptor, His-15 of HPr. A model of this conformational transition is proposed whereby swiveling around an alpha-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 approximately P and His-15 are appropriately stationed for an in-line phosphotransfer reaction.
Teplyakov
Alexey
A
Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, 9600 Gudelsky Drive, Rockville, MD 20850, USA.
Lim
Kap
K
Zhu
Peng-Peng
PP
Kapadia
Geeta
G
Chen
Celia C H
CC
Schwartz
Jennifer
J
Howard
Andrew
A
Reddy
Prasad T
PT
Peterkofsky
Alan
A
Herzberg
Osnat
O
D001665:Binding Sites; D050260:Carbohydrate Metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D004926:Escherichia coli / Q000201:enzymology; D006639:Histidine / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D010728:Phosphoenolpyruvate / Q000737:chemistry* / Q000378:metabolism*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D017852:Phosphotransferases (Nitrogenous Group Acceptor) / Q000737:chemistry* / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
D006639:Histidine; D010728:Phosphoenolpyruvate; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D017852:Phosphotransferases (Nitrogenous Group Acceptor); C022360:phosphoenolpyruvate-protein phosphotransferase