2fgr
From Proteopedia
|
High resolution Xray structure of Omp32
Overview
The porin Omp32 is the major outer membrane protein of the bacterium, Delftia acidovorans. The crystal structures of the strongly, anion-selective porin alone and in complex with the substrate malate were, solved at 1.5 and 1.45 A resolution, respectively, and revealed a, malate-binding motif adjacent to the channel constriction zone. Binding is, mediated by interaction with a cluster of two arginine residues and two, threonines. This binding site is specific for Omp32 and reflects the, physiological adaptation of the organism to organic acids. Structural, studies are combined with a 7-ns unbiased molecular dynamics simulation of, the trimeric channel in a model membrane. Molecular dynamics trajectories, show how malate ions are efficiently captured from the surrounding bulk, solution by the electrostatic potential of the channel, translocated to, the binding site region, and immobilized in the constriction zone. In, accordance with these results, conductance measurements with Omp32, inserted in planar lipid membranes revealed binding of malate. The, anion-selective channel Omp32 is the first reported example of a porin, with a 16-stranded beta-barrel and proven substrate specificity. This, finding suggests a new view on the correlation of porin structure with, substrate binding in specific channels.
About this Structure
2FGR is a Single protein structure of sequence from Delftia acidovorans with CA and SO4 as ligands. Full crystallographic information is available from OCA.
Reference
High resolution crystal structures and molecular dynamics studies reveal substrate binding in the porin Omp32., Zachariae U, Kluhspies T, De S, Engelhardt H, Zeth K, J Biol Chem. 2006 Mar 17;281(11):7413-20. Epub 2006 Jan 23. PMID:16434398
Page seeded by OCA on Wed Nov 21 10:32:50 2007
