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| | {{STRUCTURE_1qm7| PDB=1qm7 | SCENE= }} | | {{STRUCTURE_1qm7| PDB=1qm7 | SCENE= }} |
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| - | '''X-RAY STRUCTURE OF A THREE-FINGERED CHIMERIC PROTEIN, STABILITY OF A STRUCTURAL SCAFFOLD'''
| + | ===X-RAY STRUCTURE OF A THREE-FINGERED CHIMERIC PROTEIN, STABILITY OF A STRUCTURAL SCAFFOLD=== |
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| - | ==Overview==
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| - | Fasciculin 2 and toxin alpha proteins belong to the same structural family of three-fingered snake toxins. They act on different targets, but in each case the binding region involves residues from loops I and II. The superimposition of the two structures suggests that these functional regions correspond to structurally distinct zones. Loop I, half of loop II and the C-terminal residue of fasciculin 2 were therefore transferred into the toxin alpha. The inhibition constant of the resulting chimera is only 15-fold lower than that of fasciculin 2, and as expected the potency of binding to the toxin alpha target has been lost. In order to understand the structure-function relationship between the chimera and its "parent" molecules, we solved its structure by X-ray crystallography. The protein crystallized in space group P3(1)21 with a=b=58.5 A, and c=62.3 A. The crystal structure was solved by molecular replacement and refined to 2.1 A resolution. The structure belongs to the three-fingered snake toxin family with a core of four disulphide bridges from which emerge the three loops I, II and III. Superimposition of the chimera on fasciculin 2 or toxin alpha revealed an overall fold intermediate between those of the two parent molecules. The regions corresponding to toxin alpha and to fasciculin 2 retained their respective geometries. In addition, the chimera protein displayed a structural behaviour similar to that of fasciculin 2, i.e. dimerization in the crystal structure of fasciculin 2, and the geometry of the region that binds to acetylcholinesterase. In conclusion, this structure shows that the chimera retains the general structural characteristics of three-fingered toxins, and the structural specificity of the transferred function.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_10686100}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 10686100 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_10686100}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Ricciardi, A.]] | | [[Category: Ricciardi, A.]] |
| | [[Category: Stability of a structural scaffold]] | | [[Category: Stability of a structural scaffold]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:26:31 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 18:39:17 2008'' |
Revision as of 15:39, 27 July 2008
Template:STRUCTURE 1qm7
X-RAY STRUCTURE OF A THREE-FINGERED CHIMERIC PROTEIN, STABILITY OF A STRUCTURAL SCAFFOLD
Template:ABSTRACT PUBMED 10686100
About this Structure
Full crystallographic information is available from OCA.
Reference
Stability of a structural scaffold upon activity transfer: X-ray structure of a three fingers chimeric protein., Le Du MH, Ricciardi A, Khayati M, Menez R, Boulain JC, Menez A, Ducancel F, J Mol Biol. 2000 Mar 3;296(4):1017-26. PMID:10686100
Page seeded by OCA on Sun Jul 27 18:39:17 2008
