1tqq
From Proteopedia
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| - | [[Image:1tqq.jpg|left|200px]] | + | [[Image:1tqq.jpg|left|200px]] |
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| - | '''Structure of TolC in complex with hexamminecobalt''' | + | {{Structure |
| + | |PDB= 1tqq |SIZE=350|CAPTION= <scene name='initialview01'>1tqq</scene>, resolution 2.75Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=NCO:COBALT HEXAMMINE ION'>NCO</scene> | ||
| + | |ACTIVITY= | ||
| + | |GENE= TOLC, MTCB, MUKA, REFI, B3035 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=562 Escherichia coli]) | ||
| + | }} | ||
| + | |||
| + | '''Structure of TolC in complex with hexamminecobalt''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1TQQ is a [ | + | 1TQQ is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TQQ OCA]. |
==Reference== | ==Reference== | ||
| - | Structure of the ligand-blocked periplasmic entrance of the bacterial multidrug efflux protein TolC., Higgins MK, Eswaran J, Edwards P, Schertler GF, Hughes C, Koronakis V, J Mol Biol. 2004 Sep 17;342(3):697-702. PMID:[http:// | + | Structure of the ligand-blocked periplasmic entrance of the bacterial multidrug efflux protein TolC., Higgins MK, Eswaran J, Edwards P, Schertler GF, Hughes C, Koronakis V, J Mol Biol. 2004 Sep 17;342(3):697-702. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15342230 15342230] |
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
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[[Category: beta-barrel]] | [[Category: beta-barrel]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 14:21:57 2008'' |
Revision as of 12:21, 20 March 2008
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| , resolution 2.75Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Gene: | TOLC, MTCB, MUKA, REFI, B3035 (Escherichia coli) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
Structure of TolC in complex with hexamminecobalt
Overview
The trimeric TolC protein of Escherichia coli comprises an outer membrane beta-barrel and a contiguous alpha-helical barrel projecting across the periplasm. This provides a single 140 A long pore for multidrug efflux and protein export. We have previously reported that trivalent cations such as hexammine cobalt can severely inhibit the conductivity of the TolC pore reconstituted in planar lipid bilayers. Here, isothermal calorimetry shows that Co(NH(3))(6)(3+) binds to TolC with an affinity of 20 nM. The crystal structure of the TolC-Co(NH(3))(6)(3+) complex was determined to 2.75 A resolution, and showed no significant difference in the protein when compared with unliganded TolC. An electron density difference map revealed that a single ligand molecule binds at the centre of the periplasmic entrance, the sole constriction of TolC. The octahedral symmetry of the ligand and the three-fold rotational symmetry of the TolC entrance determine a binding site in which the ligand forms hydrogen bonds with the Asp(374) residue of each monomer. When Asp(374) was substituted by alanine, high affinity ligand binding was abolished and inhibition of TolC pore conductivity in lipid bilayers was alleviated. Comparable effects followed independent substitution of the neighbouring Asp(371), indicating that this aspartate ring also contributes to the high affinity ligand binding site. As the electronegative entrance is widely conserved in the TolC family, it may be a useful target for the development of inhibitors against multidrug resistant pathogenic bacteria.
About this Structure
1TQQ is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure of the ligand-blocked periplasmic entrance of the bacterial multidrug efflux protein TolC., Higgins MK, Eswaran J, Edwards P, Schertler GF, Hughes C, Koronakis V, J Mol Biol. 2004 Sep 17;342(3):697-702. PMID:15342230
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