1lda: Difference between revisions
New page: left|200px<br /><applet load="1lda" size="450" color="white" frame="true" align="right" spinBox="true" caption="1lda, resolution 2.80Å" /> '''CRYSTAL STRUCTURE OF... |
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[[Image:1lda.jpg|left|200px]]<br /><applet load="1lda" size=" | [[Image:1lda.jpg|left|200px]]<br /><applet load="1lda" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1lda, resolution 2.80Å" /> | caption="1lda, resolution 2.80Å" /> | ||
'''CRYSTAL STRUCTURE OF THE E. COLI GLYCEROL FACILITATOR (GLPF) WITHOUT SUBSTRATE GLYCEROL'''<br /> | '''CRYSTAL STRUCTURE OF THE E. COLI GLYCEROL FACILITATOR (GLPF) WITHOUT SUBSTRATE GLYCEROL'''<br /> | ||
==Overview== | ==Overview== | ||
Aquaporins are transmembrane channels found in cell membranes of all life | Aquaporins are transmembrane channels found in cell membranes of all life forms. We examine their apparently paradoxical property, facilitation of efficient permeation of water while excluding protons, which is of critical importance to preserving the electrochemical potential across the cell membrane. We have determined the structure of the Escherichia coli aquaglyceroporin GlpF with bound water, in native (2.7 angstroms) and in W48F/F200T mutant (2.1 angstroms) forms, and carried out 12-nanosecond molecular dynamics simulations that define the spatial and temporal probability distribution and orientation of a single file of seven to nine water molecules inside the channel. Two conserved asparagines force a central water molecule to serve strictly as a hydrogen bond donor to its neighboring water molecules. Assisted by the electrostatic potential generated by two half-membrane spanning loops, this dictates opposite orientations of water molecules in the two halves of the channel, and thus prevents the formation of a "proton wire," while permitting rapid water diffusion. Both simulations and observations revealed a more regular distribution of channel water and an increased water permeability for the W48F/F200T mutant. | ||
==About this Structure== | ==About this Structure== | ||
1LDA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with BOG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1LDA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=BOG:'>BOG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LDA OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Connell, J | [[Category: Connell, J O.]] | ||
[[Category: Miercke, L | [[Category: Miercke, L J.W.]] | ||
[[Category: Nollert, P.]] | [[Category: Nollert, P.]] | ||
[[Category: Stroud, R | [[Category: Stroud, R M.]] | ||
[[Category: BOG]] | [[Category: BOG]] | ||
[[Category: glycerol-conducting membrane channel protein]] | [[Category: glycerol-conducting membrane channel protein]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:43:53 2008'' | ||
Revision as of 14:43, 21 February 2008
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CRYSTAL STRUCTURE OF THE E. COLI GLYCEROL FACILITATOR (GLPF) WITHOUT SUBSTRATE GLYCEROL
OverviewOverview
Aquaporins are transmembrane channels found in cell membranes of all life forms. We examine their apparently paradoxical property, facilitation of efficient permeation of water while excluding protons, which is of critical importance to preserving the electrochemical potential across the cell membrane. We have determined the structure of the Escherichia coli aquaglyceroporin GlpF with bound water, in native (2.7 angstroms) and in W48F/F200T mutant (2.1 angstroms) forms, and carried out 12-nanosecond molecular dynamics simulations that define the spatial and temporal probability distribution and orientation of a single file of seven to nine water molecules inside the channel. Two conserved asparagines force a central water molecule to serve strictly as a hydrogen bond donor to its neighboring water molecules. Assisted by the electrostatic potential generated by two half-membrane spanning loops, this dictates opposite orientations of water molecules in the two halves of the channel, and thus prevents the formation of a "proton wire," while permitting rapid water diffusion. Both simulations and observations revealed a more regular distribution of channel water and an increased water permeability for the W48F/F200T mutant.
About this StructureAbout this Structure
1LDA is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Control of the selectivity of the aquaporin water channel family by global orientational tuning., Tajkhorshid E, Nollert P, Jensen MO, Miercke LJ, O'Connell J, Stroud RM, Schulten K, Science. 2002 Apr 19;296(5567):525-30. PMID:11964478
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