title: New molecular interaction of IIA(Ntr) and HPr from Burkholderia pseudomallei identified by X-ray crystallography and docking studies.
abstract: The nitrogen-related phosphoenolpyruvate phosphotransferase system (PTS(Ntr) ) is involved in controlling ammonia assimilation and nitrogen fixation. The additional role of PTS(Ntr) as a regulatory link between nitrogen and carbon utilization in Escherichia coli is assumed to be closely related to molecular functions of IIA(Ntr) in potassium homeostasis. We have determined the crystal structure of IIA(Ntr) from Burkholderia pseudomallei (BpIIA(Ntr) ), which is a causative agent of melioidosis. The crystal structure of dimeric BpIIA(Ntr) determined at 3.0 Å revealed that its active sites are mutually blocked. This dimeric state is stabilized by charge and weak hydrophobic interactions. Overall monomeric structure and the active site residues, Arg51 and His67, of BpIIA(Ntr) are well conserved with those of IIA(Ntr) enzymes from E. coli and Neisseria meningitides. Interestingly, His113 of BpIIA(Ntr) , which corresponds to a key residue in another phosphoryl group relay in the mannitol-specific enzyme EIIA family (EIIA(Mtl) ), is located away from the active site due to the loop connecting β5 and α3. Combined with other differences in molecular surface properties, these structural signatures distinguish the IIA(Ntr) family from the EIIA(Mtl) family. Since, there is no gene for NPr in the chromosome of B. pseudomallei, modeling and docking studies of the BpIIA(Ntr) -BpHPr complex has been performed to support the proposal on the NPr-like activity of BpHPr. A potential dual role of BpHPr as a nonspecific phosphocarrier protein interacting with both sugar EIIAs and IIA(Ntr) in B. pseudomallei has been discussed.
authors.affiliation: Division of Life & Pharmaceutical Sciences, The Center for Cell Signaling & Drug Discovery Research, College of Pharmacy, Ewha Womans University, Seoul, 120-750, Republic of Korea.
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Kim
authors.forename: Hasup
authors.initials: H
authors.lastname: Lee
authors.forename: Lim
authors.initials: L
authors.lastname: Heo
authors.forename: Areum
authors.initials: A
authors.lastname: Lim
authors.forename: Chaok
authors.initials: C
authors.lastname: Seok
authors.forename: Dong Hae
authors.initials: DH
authors.lastname: Shin
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D016957:Burkholderia pseudomallei / Q000201:enzymology* / Q000235:genetics; D018360:Crystallography, X-Ray; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System
keywords: HPr; IIANtr; NPr; crystal structure; nitrogen-related phosphoenolpyruvate phosphotransferase system