2lig

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spinqualitylabelsall models 2lig, resolution 2.0Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

THREE-DIMENSIONAL STRUCTURES OF THE LIGAND-BINDING DOMAIN OF THE BACTERIAL ASPARTATE RECEPTOR WITH AND WITHOUT A LIGAND

Overview

The three-dimensional structure of an active, disulfide cross-linked dimer, of the ligand-binding domain of the Salmonella typhimurium aspartate, receptor and that of an aspartate complex have been determined by x-ray, crystallographic methods at 2.4 and 2.0 angstrom (A) resolution, respectively. A single subunit is a four-alpha-helix bundle with two long, amino-terminal and carboxyl-terminal helices and two shorter helices that, form a cylinder 20 A in diameter and more than 70 A long. The two subunits, in the disulfide-bonded dimer are related by a crystallographic twofold, axis in the apo structure, but by a noncrystallographic twofold axis in, the aspartate complex structure. The latter structure reveals that the, ligand binding site is located more than 60 A from the presumed membrane, surface and is at the interface of the two subunits. Aspartate binds, between two alpha helices from one subunit and one alpha helix from the, other in a highly charged pocket formed by three arginines. The comparison, of the apo and aspartate complex structures shows only small structural, changes in the individual subunits, except for one loop region that is, disordered, but the subunits appear to change orientation relative to each, other. The structures of the two forms of this protein provide a step, toward understanding the mechanisms of transmembrane signaling.

About this Structure

2LIG is a Single protein structure of sequence from Salmonella typhimurium with SO4, ASP and PHN as ligands. Full crystallographic information is available from OCA.

Reference

Three-dimensional structures of the ligand-binding domain of the bacterial aspartate receptor with and without a ligand., Milburn MV, Prive GG, Milligan DL, Scott WG, Yeh J, Jancarik J, Koshland DE Jr, Kim SH, Science. 1991 Nov 29;254(5036):1342-7. PMID:1660187

Page seeded by OCA on Wed Nov 21 12:42:08 2007