1hpb
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1hpb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hpb, resolution 2.5Å" /> '''THE BACTERIAL PERIPLA...)
Next diff →
Revision as of 14:36, 20 November 2007
|
THE BACTERIAL PERIPLASMIC HISTIDINE-BINDING PROTEIN: STRUCTURE(SLASH)FUNCTION ANALYSIS OF THE LIGAND-BINDING SITE AND COMPARISON WITH RELATED PROTEINS
Overview
Bacterial periplasmic binding proteins are initial receptors in the, process of active transport across cell membranes and/or chemotaxis. Among, them, the histidine-binding protein (HisJ) has been extensively studied, from the biochemical, physiological, and genetic points of view. The, three-dimensional crystal structure of the histidine-binding protein, complexed with histidine has been determined at 2.5-A resolution by the, molecular replacement method using a probe structure the previously solved, lysine-liganded structure of the lysine-, arginine-, ornithine-binding, protein (LAO), which shares 70% sequence identity with HisJ. The structure, is bi-lobate; the two lobes, one bigger than the other, are connected by, two short strands and are in contact with each other (closed) enclosing, the histidine. Charged, polar, and non-polar side chains, as well as the, peptide backbone, are involved in tight binding of the histidine. The, bound histidine is involved in eight direct hydrogen bonds, six with the, bigger lobe and two with the smaller lobe, in one potential water-mediated, hydrogen bond with the bigger lobe, as well as in ionic interactions. The, HisJ residues surrounding the ligand are the same as the LAO residues, interacting with lysine, except for residue 52 which is leucine in HisJ, and phenylalanine in LAO. The Leu-52 in HisJ makes a hydrophobic, interaction with the imidazole ring of histidine. Of seven mutations, affecting the ligand-binding site, five are located in the ligand-binding, site, one in a connecting strand, and one at the domains interface. Based, on comparisons among related binding proteins, the specific interactions, between the ligands and the respective binding protein residues are, predicted for the glutamine-binding protein and the opines-binding, protein.
About this Structure
1HPB is a Single protein structure of sequence from Salmonella typhimurium with HIS as ligand. Full crystallographic information is available from OCA.
Reference
The bacterial periplasmic histidine-binding protein. structure/function analysis of the ligand-binding site and comparison with related proteins., Oh BH, Kang CH, De Bondt H, Kim SH, Nikaido K, Joshi AK, Ames GF, J Biol Chem. 1994 Feb 11;269(6):4135-43. PMID:8307974
Page seeded by OCA on Tue Nov 20 16:43:27 2007
