2glg
From Proteopedia
(New page: 200px<br /><applet load="2glg" size="450" color="white" frame="true" align="right" spinBox="true" caption="2glg" /> '''NMR structure of the [L23,A24]-sCT mutant'''...) |
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| - | [[Image:2glg.gif|left|200px]]<br /><applet load="2glg" size=" | + | [[Image:2glg.gif|left|200px]]<br /><applet load="2glg" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2glg" /> | caption="2glg" /> | ||
'''NMR structure of the [L23,A24]-sCT mutant'''<br /> | '''NMR structure of the [L23,A24]-sCT mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Salmon calcitonin (sCT) forms an amphipathic helix in the region 9-19, with the C-terminal decapeptide interacting with the helix (Amodeo, P., Motta, A., Strazzullo, G., Castiglione Morelli, M. A. (1999) J. Biomol. | + | Salmon calcitonin (sCT) forms an amphipathic helix in the region 9-19, with the C-terminal decapeptide interacting with the helix (Amodeo, P., Motta, A., Strazzullo, G., Castiglione Morelli, M. A. (1999) J. Biomol. NMR 13, 161-174). To uncover the structural requirements for the hormone bioactivity, we investigated several sCT analogs. They were designed so as to alter the length of the central helix by removal and/or replacement of flanking residues and by selectively mutating or deleting residues inside the helix. The helix content was assessed by circular dichroism and NMR spectroscopies; the receptor binding affinity in human breast cancer cell line T 47D and the in vivo hypocalcemic activity were also evaluated. In particular, by NMR spectroscopy and molecular dynamics calculations we studied Leu(23),Ala(24)-sCT in which Pro(23) and Arg(24) were replaced by helix inducing residues. Compared with sCT, it assumes a longer amphipathic alpha-helix, with decreased binding affinity and one-fifth of the hypocalcemic activity, therefore supporting the idea of a relationship between a definite helix length and bioactivity. From the analysis of other sCT mutants, we inferred that the correct helix length is located in the 9-19 region and requires long range interactions and the presence of specific regions of residues within the sequence for high binding affinity and hypocalcemic activity. Taken together, the structural and biological data identify well defined structural parameters of the helix for sCT bioactivity. |
==About this Structure== | ==About this Structure== | ||
| - | 2GLG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with NH2 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 2GLG is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ] with <scene name='pdbligand=NH2:'>NH2</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GLG OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Andreotti, G.]] | [[Category: Andreotti, G.]] | ||
[[Category: Lopez-Mendez, B.]] | [[Category: Lopez-Mendez, B.]] | ||
| - | [[Category: Morelli, M | + | [[Category: Morelli, M A.]] |
[[Category: Motta, A.]] | [[Category: Motta, A.]] | ||
[[Category: Nakamuta, H.]] | [[Category: Nakamuta, H.]] | ||
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[[Category: a-helix]] | [[Category: a-helix]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:32:48 2008'' |
Revision as of 15:32, 21 February 2008
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NMR structure of the [L23,A24]-sCT mutant
Overview
Salmon calcitonin (sCT) forms an amphipathic helix in the region 9-19, with the C-terminal decapeptide interacting with the helix (Amodeo, P., Motta, A., Strazzullo, G., Castiglione Morelli, M. A. (1999) J. Biomol. NMR 13, 161-174). To uncover the structural requirements for the hormone bioactivity, we investigated several sCT analogs. They were designed so as to alter the length of the central helix by removal and/or replacement of flanking residues and by selectively mutating or deleting residues inside the helix. The helix content was assessed by circular dichroism and NMR spectroscopies; the receptor binding affinity in human breast cancer cell line T 47D and the in vivo hypocalcemic activity were also evaluated. In particular, by NMR spectroscopy and molecular dynamics calculations we studied Leu(23),Ala(24)-sCT in which Pro(23) and Arg(24) were replaced by helix inducing residues. Compared with sCT, it assumes a longer amphipathic alpha-helix, with decreased binding affinity and one-fifth of the hypocalcemic activity, therefore supporting the idea of a relationship between a definite helix length and bioactivity. From the analysis of other sCT mutants, we inferred that the correct helix length is located in the 9-19 region and requires long range interactions and the presence of specific regions of residues within the sequence for high binding affinity and hypocalcemic activity. Taken together, the structural and biological data identify well defined structural parameters of the helix for sCT bioactivity.
About this Structure
2GLG is a Single protein structure of sequence from [1] with as ligand. Full crystallographic information is available from OCA.
Reference
Structural determinants of salmon calcitonin bioactivity: the role of the Leu-based amphipathic alpha-helix., Andreotti G, Mendez BL, Amodeo P, Morelli MA, Nakamuta H, Motta A, J Biol Chem. 2006 Aug 25;281(34):24193-203. Epub 2006 Jun 9. PMID:16766525
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