title: Proposed carrier lipid-binding site of undecaprenyl pyrophosphate phosphatase from Escherichia coli.
abstract: Undecaprenyl pyrophosphate phosphatase (UppP), an integral membrane protein, catalyzes the dephosphorylation of undecaprenyl pyrophosphate to undecaprenyl phosphate, which is an essential carrier lipid in the bacterial cell wall synthesis. Sequence alignment reveals two consensus regions, containing glutamate-rich (E/Q)XXXE plus PGXSRSXXT motifs and a histidine residue, specific to the bacterial UppP enzymes. The predicted topological model suggests that both of these regions are localized near the aqueous interface of UppP and face the periplasm, implicating that its enzymatic function is on the outer side of the plasma membrane. The mutagenesis analysis demonstrates that most of the mutations (E17A/E21A, H30A, S173A, R174A, and T178A) within the consensus regions are completely inactive, indicating that the catalytic site of UppP is constituted by these two regions. Enzymatic analysis also shows an absolute requirement of magnesium or calcium ions in enzyme activity. The three-dimensional structural model and molecular dynamics simulation studies have shown a plausible structure of the catalytic site of UppP and thus provides insights into the molecular basis of the enzyme-substrate interaction in membrane bilayers.
authors.affiliation: From the Institute of Biological Chemistry and.
authors.forename: Hsin-Yang
authors.initials: HY
authors.lastname: Chang
authors.affiliation: From the Institute of Biological Chemistry and Core Facilities for Protein Structural Analysis Academia Sinica, Taipei and.
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Chou
authors.affiliation: From the Institute of Biological Chemistry and Core Facilities for Protein Structural Analysis Academia Sinica, Taipei and.
authors.forename: Min-Feng
authors.initials: MF
authors.lastname: Hsu
authors.affiliation: From the Institute of Biological Chemistry and Core Facilities for Protein Structural Analysis Academia Sinica, Taipei and the Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei 11529, Taiwan ahjwang@gate.sinica.edu.tw.
authors.forename: Andrew H J
authors.initials: AH
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D055162:Biocatalysis; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D008051:Lipid Bilayers / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism*; D008670:Metals / Q000494:pharmacology; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D008051:Lipid Bilayers; D008563:Membrane Lipids; D008670:Metals; D011755:Pyrophosphatases; C503879:undecaprenyl pyrophosphate phosphatase
keywords: BacA; Computer Modeling; Enzyme Catalysis; Enzyme Kinetics; Enzyme Structure; Mutagenesis; Undecaprenyl Pyrophosphate Phosphatase; UppP