1nqm
From Proteopedia
(New page: 200px<br /><applet load="1nqm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nqm, resolution 1.7Å" /> '''Structure of Savm-W12...) |
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| - | [[Image:1nqm.gif|left|200px]]<br /><applet load="1nqm" size=" | + | [[Image:1nqm.gif|left|200px]]<br /><applet load="1nqm" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1nqm, resolution 1.7Å" /> | caption="1nqm, resolution 1.7Å" /> | ||
'''Structure of Savm-W120K, streptavidin mutant'''<br /> | '''Structure of Savm-W120K, streptavidin mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The biotin-binding tetrameric proteins, streptavidin from Streptomyces | + | The biotin-binding tetrameric proteins, streptavidin from Streptomyces avidinii and chicken egg white avidin, are excellent models for the study of subunit-subunit interactions of a multimeric protein. Efforts are thus being made to prepare mutated forms of streptavidin and avidin, which would form monomers or dimers, in order to examine their effect on quaternary structure and assembly. In the present communication, we compared the crystal structures of binding site W-->K mutations in streptavidin and avidin. In solution, both mutant proteins are known to form dimers, but upon crystallization, both formed tetramers with the same parameters as the native proteins. All of the intersubunit bonds were conserved, except for the hydrophobic interaction between biotin and the tryptophan that was replaced by lysine. In the crystal structure, the binding site of the mutated apo-avidin contains 3 molecules of structured water instead of the 5 contained in the native protein. The lysine side chain extends in a direction opposite that of the native tryptophan, the void being partially filled by an adjacent lysine residue. Nevertheless, the binding-site conformation observed for the mutant tetramer is an artificial consequence of crystal packing that would not be maintained in the solution-phase dimer. It appears that the dimer-tetramer transition may be concentration dependent, and the interaction among subunits obeys the law of mass action. |
==About this Structure== | ==About this Structure== | ||
| - | 1NQM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_avidinii Streptomyces avidinii] with BTN as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1NQM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_avidinii Streptomyces avidinii] with <scene name='pdbligand=BTN:'>BTN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NQM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptomyces avidinii]] | [[Category: Streptomyces avidinii]] | ||
| - | [[Category: Bayer, E | + | [[Category: Bayer, E A.]] |
[[Category: Eisenberg-Domovich, Y.]] | [[Category: Eisenberg-Domovich, Y.]] | ||
| - | [[Category: Kulomaa, M | + | [[Category: Kulomaa, M S.]] |
| - | [[Category: Laitinen, O | + | [[Category: Laitinen, O H.]] |
[[Category: Livnah, O.]] | [[Category: Livnah, O.]] | ||
[[Category: Pazy, Y.]] | [[Category: Pazy, Y.]] | ||
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[[Category: streptavidin]] | [[Category: streptavidin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:09:05 2008'' |
Revision as of 12:09, 21 February 2008
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Structure of Savm-W120K, streptavidin mutant
Overview
The biotin-binding tetrameric proteins, streptavidin from Streptomyces avidinii and chicken egg white avidin, are excellent models for the study of subunit-subunit interactions of a multimeric protein. Efforts are thus being made to prepare mutated forms of streptavidin and avidin, which would form monomers or dimers, in order to examine their effect on quaternary structure and assembly. In the present communication, we compared the crystal structures of binding site W-->K mutations in streptavidin and avidin. In solution, both mutant proteins are known to form dimers, but upon crystallization, both formed tetramers with the same parameters as the native proteins. All of the intersubunit bonds were conserved, except for the hydrophobic interaction between biotin and the tryptophan that was replaced by lysine. In the crystal structure, the binding site of the mutated apo-avidin contains 3 molecules of structured water instead of the 5 contained in the native protein. The lysine side chain extends in a direction opposite that of the native tryptophan, the void being partially filled by an adjacent lysine residue. Nevertheless, the binding-site conformation observed for the mutant tetramer is an artificial consequence of crystal packing that would not be maintained in the solution-phase dimer. It appears that the dimer-tetramer transition may be concentration dependent, and the interaction among subunits obeys the law of mass action.
About this Structure
1NQM is a Single protein structure of sequence from Streptomyces avidinii with as ligand. Full crystallographic information is available from OCA.
Reference
Dimer-tetramer transition between solution and crystalline states of streptavidin and avidin mutants., Pazy Y, Eisenberg-Domovich Y, Laitinen OH, Kulomaa MS, Bayer EA, Wilchek M, Livnah O, J Bacteriol. 2003 Jul;185(14):4050-6. PMID:12837778
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