3b5y
From Proteopedia
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==Overview== | ==Overview== | ||
| - | ATP-binding cassette (ABC) transporters are integral membrane proteins | + | ATP-binding cassette (ABC) transporters are integral membrane proteins that translocate a wide variety of substrates across cellular membranes and are conserved from bacteria to humans. Here we compare four x-ray structures of the bacterial ABC lipid flippase, MsbA, trapped in different conformations, two nucleotide-bound structures and two in the absence of nucleotide. Comparison of the nucleotide-free conformations of MsbA reveals a flexible hinge formed by extracellular loops 2 and 3. This hinge allows the nucleotide-binding domains to disassociate while the ATP-binding half sites remain facing each other. The binding of the nucleotide causes a packing rearrangement of the transmembrane helices and changes the accessibility of the transporter from cytoplasmic (inward) facing to extracellular (outward) facing. The inward and outward openings are mediated by two different sets of transmembrane helix interactions. Altogether, the conformational changes between these structures suggest that large ranges of motion may be required for substrate transport. |
==About this Structure== | ==About this Structure== | ||
| - | 3B5Y is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with <scene name='pdbligand=ANP:'>ANP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Known structural/functional Sites: <scene name='pdbsite=AC1:Anp Binding Site For Residue B 5001'>AC1</scene>, <scene name='pdbsite=AC2:Anp Binding Site For Residue A 5002'>AC2</scene>, <scene name='pdbsite=AC3:Anp Binding Site For Residue D 5003'>AC3</scene> and <scene name='pdbsite=AC4:Anp Binding Site For Residue C 5004'>AC4</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3B5Y OCA]. | + | 3B5Y is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with <scene name='pdbligand=ANP:'>ANP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Known structural/functional Sites: <scene name='pdbsite=AC1:Anp+Binding+Site+For+Residue+B+5001'>AC1</scene>, <scene name='pdbsite=AC2:Anp+Binding+Site+For+Residue+A+5002'>AC2</scene>, <scene name='pdbsite=AC3:Anp+Binding+Site+For+Residue+D+5003'>AC3</scene> and <scene name='pdbsite=AC4:Anp+Binding+Site+For+Residue+C+5004'>AC4</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3B5Y OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Salmonella typhimurium]] | [[Category: Salmonella typhimurium]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Reyes, C | + | [[Category: Reyes, C L.]] |
| - | [[Category: Roth, C | + | [[Category: Roth, C B.]] |
[[Category: Ward, A.]] | [[Category: Ward, A.]] | ||
[[Category: Yu, J.]] | [[Category: Yu, J.]] | ||
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[[Category: transmembrane]] | [[Category: transmembrane]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:03:30 2008'' |
Revision as of 17:03, 21 February 2008
|
Crystal Structure of MsbA from Salmonella typhimurium with AMPPNP
Overview
ATP-binding cassette (ABC) transporters are integral membrane proteins that translocate a wide variety of substrates across cellular membranes and are conserved from bacteria to humans. Here we compare four x-ray structures of the bacterial ABC lipid flippase, MsbA, trapped in different conformations, two nucleotide-bound structures and two in the absence of nucleotide. Comparison of the nucleotide-free conformations of MsbA reveals a flexible hinge formed by extracellular loops 2 and 3. This hinge allows the nucleotide-binding domains to disassociate while the ATP-binding half sites remain facing each other. The binding of the nucleotide causes a packing rearrangement of the transmembrane helices and changes the accessibility of the transporter from cytoplasmic (inward) facing to extracellular (outward) facing. The inward and outward openings are mediated by two different sets of transmembrane helix interactions. Altogether, the conformational changes between these structures suggest that large ranges of motion may be required for substrate transport.
About this Structure
3B5Y is a Single protein structure of sequence from Salmonella typhimurium with as ligand. Known structural/functional Sites: , , and . Full crystallographic information is available from OCA.
Reference
Flexibility in the ABC transporter MsbA: Alternating access with a twist., Ward A, Reyes CL, Yu J, Roth CB, Chang G, Proc Natl Acad Sci U S A. 2007 Nov 27;104(48):19005-10. Epub 2007 Nov 16. PMID:18024585
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