2eyb: Difference between revisions
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'''Water refined solution structure of crambin in ACETONE/WATER'''<br /> | '''Water refined solution structure of crambin in ACETONE/WATER'''<br /> | ||
==Overview== | ==Overview== | ||
We chose crambin, a hydrophobic and water-insoluble protein originally | We chose crambin, a hydrophobic and water-insoluble protein originally isolated from the seeds of the plant Crambe abyssinica, as a model for NMR investigations of membrane-associated proteins. We produced isotopically labeled crambin(P22,L25) (variant of crambin containing Pro22 and Leu25) as a cleavable fusion with staphylococcal nuclease and refolded the protein by an approach that has proved successful for the production of proteins with multiple disulfide bonds. We used NMR spectroscopy to determine the three-dimensional structure of the protein in two membrane-mimetic environments: in a mixed aqueous-organic solvent (75%/25%, acetone/water) and in DPC micelles. With the sample in the mixed solvent, it was possible to determine (>NH...OC<) hydrogen bonds directly by the detection of (h3)J(NC)' couplings. H-bonds determined in this manner were utilized in the refinement of the NMR-derived protein structures. With the protein in DPC (dodecylphosphocholine) micelles, we used manganous ion as an aqueous paramagnetic probe to determine the surface of crambin that is shielded by the detergent. With the exception of the aqueous solvent exposed loop containing residues 20 and 21, the protein surface was protected by DPC. This suggests that the protein may be similarly embedded in physiological membranes. The strategy described here for the expression and structure determination of crambin should be applicable to structural and functional studies of membrane active toxins and small membrane proteins. | ||
==About this Structure== | ==About this Structure== | ||
2EYB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Crambe_hispanica_subsp._abyssinica Crambe hispanica subsp. abyssinica]. Full crystallographic information is available from [http:// | 2EYB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Crambe_hispanica_subsp._abyssinica Crambe hispanica subsp. abyssinica]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2EYB OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Crambe hispanica subsp. abyssinica]] | [[Category: Crambe hispanica subsp. abyssinica]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Ahn, H | [[Category: Ahn, H C.]] | ||
[[Category: Markley, J | [[Category: Markley, J L.]] | ||
[[Category: crambin]] | [[Category: crambin]] | ||
[[Category: mixed organic/aqueous solvent]] | [[Category: mixed organic/aqueous solvent]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:15:52 2008'' | ||
Revision as of 18:15, 21 February 2008
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Water refined solution structure of crambin in ACETONE/WATER
OverviewOverview
We chose crambin, a hydrophobic and water-insoluble protein originally isolated from the seeds of the plant Crambe abyssinica, as a model for NMR investigations of membrane-associated proteins. We produced isotopically labeled crambin(P22,L25) (variant of crambin containing Pro22 and Leu25) as a cleavable fusion with staphylococcal nuclease and refolded the protein by an approach that has proved successful for the production of proteins with multiple disulfide bonds. We used NMR spectroscopy to determine the three-dimensional structure of the protein in two membrane-mimetic environments: in a mixed aqueous-organic solvent (75%/25%, acetone/water) and in DPC micelles. With the sample in the mixed solvent, it was possible to determine (>NH...OC<) hydrogen bonds directly by the detection of (h3)J(NC)' couplings. H-bonds determined in this manner were utilized in the refinement of the NMR-derived protein structures. With the protein in DPC (dodecylphosphocholine) micelles, we used manganous ion as an aqueous paramagnetic probe to determine the surface of crambin that is shielded by the detergent. With the exception of the aqueous solvent exposed loop containing residues 20 and 21, the protein surface was protected by DPC. This suggests that the protein may be similarly embedded in physiological membranes. The strategy described here for the expression and structure determination of crambin should be applicable to structural and functional studies of membrane active toxins and small membrane proteins.
About this StructureAbout this Structure
2EYB is a Single protein structure of sequence from Crambe hispanica subsp. abyssinica. Full crystallographic information is available from OCA.
ReferenceReference
Three-dimensional structure of the water-insoluble protein crambin in dodecylphosphocholine micelles and its minimal solvent-exposed surface., Ahn HC, Juranic N, Macura S, Markley JL, J Am Chem Soc. 2006 Apr 5;128(13):4398-404. PMID:16569017
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