title: Crystal Structure of Hypothetical Fructose-Specific EIIB from Escherichia coli.
abstract: We have solved the crystal structure of a predicted fructose-specific enzyme IIB(fruc) from Escherichia coli (EcEIIB(fruc)) involved in the phosphoenolpyruvate-carbohydrate phosphotransferase system transferring carbohydrates across the cytoplasmic membrane. EcEIIB(fruc) belongs to a sequence family with more than 5,000 sequence homologues with 25-99% amino-acid sequence identity. It reveals a conventional Rossmann-like α-β-α sandwich fold with a unique β-sheet topology. Its C-terminus is longer than its closest relatives and forms an additional β-strand whereas the shorter C-terminus is random coil in the relatives. Interestingly, its core structure is similar to that of enzyme IIB(cellobiose) from E. coli (EcIIB(cel)) transferring a phosphate moiety. In the active site of the closest EcEIIB(fruc) homologues, a unique motif CXXGXAHT comprising a P-loop like architecture including a histidine residue is found. The conserved cysteine on this loop may be deprotonated to act as a nucleophile similar to that of EcIIB(cel). The conserved histidine residue is presumed to bind the negatively charged phosphate. Therefore, we propose that the catalytic mechanism of EcEIIB(fruc) is similar to that of EcIIB(cel) transferring phosphoryl moiety to a specific carbohydrate.
authors.affiliation: College of Pharmacy and Graduate School of Pharmaceutical Sciences, Global Top5 Research Program, Ewha Womans University, Seoul 03760, Korea.
authors.forename: Jimin
authors.initials: J
authors.lastname: Park
authors.affiliation: College of Pharmacy and Graduate School of Pharmaceutical Sciences, Global Top5 Research Program, Ewha Womans University, Seoul 03760, Korea.
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Kim
authors.affiliation: Center for insilico Protein Science and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea.
authors.forename: Keehyung
authors.initials: K
authors.lastname: Joo
authors.affiliation: Department of Chemistry and Nano Science, Global Top5 Research Program, Ewha Womans University, Seoul 03760, Korea.
authors.forename: Gil-Ja
authors.initials: GJ
authors.lastname: Jhon
authors.affiliation: Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York, USA.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Berry
authors.affiliation: Center for insilico Protein Science and School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Korea.
authors.forename: Jooyoung
authors.initials: J
authors.lastname: Lee
authors.affiliation: College of Pharmacy and Graduate School of Pharmaceutical Sciences, Global Top5 Research Program, Ewha Womans University, Seoul 03760, Korea.
authors.forename: Dong Hae
authors.initials: DH
authors.lastname: Shin
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D005632:Fructose / Q000378:metabolism*; D008958:Models, Molecular; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000378:metabolism*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D005632:Fructose; C000614917:FrwD protein, E coli; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D003545:Cysteine
keywords: PTS permease; PTS system; X-ray crystallography; fructose specific enzyme EIIB; frwD; functional cysteine