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1a13
From Proteopedia
(New page: 200px<br /><applet load="1a13" size="450" color="white" frame="true" align="right" spinBox="true" caption="1a13" /> '''G PROTEIN-BOUND CONFORMATION OF MASTOPARAN-X...) |
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| - | [[Image:1a13.gif|left|200px]]<br /><applet load="1a13" size=" | + | [[Image:1a13.gif|left|200px]]<br /><applet load="1a13" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1a13" /> | caption="1a13" /> | ||
'''G PROTEIN-BOUND CONFORMATION OF MASTOPARAN-X, NMR, 14 STRUCTURES'''<br /> | '''G PROTEIN-BOUND CONFORMATION OF MASTOPARAN-X, NMR, 14 STRUCTURES'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Mastoparans, a family of tetradecapeptides from wasp venom, have been used | + | Mastoparans, a family of tetradecapeptides from wasp venom, have been used as convenient low molecular weight models of receptors coupled to GTP-binding regulatory proteins (G proteins) for the understanding of the interaction between G proteins and receptors. Sukumar and Higashijima have analyzed the conformation of mastoparan-X (MP-X) bound to the G protein alpha-subunit using proton two-dimensional transferred nuclear Overhauser effect (TRNOE) spectroscopy [Sukumar, M., and Higashijima, T. (1992) J. Biol. Chem., 267, 21421-21424]. The resultant structure, however, was not well-defined due to severe overlap of peptide proton resonances. To determine the G protein-bound conformation of MP-X in detail, we have analyzed this interaction by heteronuclear multidimensional TRNOE experiments of MP-X uniformly enriched with 15N and/or 13C. By solving the overlap problem, we were able to determine the precise conformation of MP-X bound to Gi1alpha: the peptide adopts an amphiphilic alpha-helix from Trp3 to C-terminal Leu14, and the atomic root-mean-square deviation (rmsd) values in this portion about the averaged coordinates were 0.27 +/- 0.07 A for the backbone atoms (N, Calpha, C') and 0.84 +/- 0.16 A for all heavy atoms. These values are much smaller than the corresponding rmsd values of the structures obtained from the proton 2D TRNOE spectrum alone: 1.70 +/- 0.41 A for the backbone atoms (N, Calpha, C') and 2.84 +/- 0.51 A for all heavy atoms. Our results indicate that the heteronuclear multidimensional TRNOE experiments of peptides uniformly enriched with stable isotopes are a very powerful tool for analyzing the conformation of short peptides bound to large proteins. We will also discuss the structure-activity relationships of mastoparans in activating G proteins on the basis of the precise structure of MP-X bound to Gi1alpha. |
==About this Structure== | ==About this Structure== | ||
| - | 1A13 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Vespa_simillima_xanthoptera Vespa simillima xanthoptera] with NH2 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1A13 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Vespa_simillima_xanthoptera Vespa simillima xanthoptera] 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=1A13 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: mast cell degranulation]] | [[Category: mast cell degranulation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:39:38 2008'' |
Revision as of 09:39, 21 February 2008
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G PROTEIN-BOUND CONFORMATION OF MASTOPARAN-X, NMR, 14 STRUCTURES
Overview
Mastoparans, a family of tetradecapeptides from wasp venom, have been used as convenient low molecular weight models of receptors coupled to GTP-binding regulatory proteins (G proteins) for the understanding of the interaction between G proteins and receptors. Sukumar and Higashijima have analyzed the conformation of mastoparan-X (MP-X) bound to the G protein alpha-subunit using proton two-dimensional transferred nuclear Overhauser effect (TRNOE) spectroscopy [Sukumar, M., and Higashijima, T. (1992) J. Biol. Chem., 267, 21421-21424]. The resultant structure, however, was not well-defined due to severe overlap of peptide proton resonances. To determine the G protein-bound conformation of MP-X in detail, we have analyzed this interaction by heteronuclear multidimensional TRNOE experiments of MP-X uniformly enriched with 15N and/or 13C. By solving the overlap problem, we were able to determine the precise conformation of MP-X bound to Gi1alpha: the peptide adopts an amphiphilic alpha-helix from Trp3 to C-terminal Leu14, and the atomic root-mean-square deviation (rmsd) values in this portion about the averaged coordinates were 0.27 +/- 0.07 A for the backbone atoms (N, Calpha, C') and 0.84 +/- 0.16 A for all heavy atoms. These values are much smaller than the corresponding rmsd values of the structures obtained from the proton 2D TRNOE spectrum alone: 1.70 +/- 0.41 A for the backbone atoms (N, Calpha, C') and 2.84 +/- 0.51 A for all heavy atoms. Our results indicate that the heteronuclear multidimensional TRNOE experiments of peptides uniformly enriched with stable isotopes are a very powerful tool for analyzing the conformation of short peptides bound to large proteins. We will also discuss the structure-activity relationships of mastoparans in activating G proteins on the basis of the precise structure of MP-X bound to Gi1alpha.
About this Structure
1A13 is a Single protein structure of sequence from Vespa simillima xanthoptera with as ligand. Full crystallographic information is available from OCA.
Reference
G protein-bound conformation of mastoparan-X: heteronuclear multidimensional transferred nuclear overhauser effect analysis of peptide uniformly enriched with 13C and 15N., Kusunoki H, Wakamatsu K, Sato K, Miyazawa T, Kohno T, Biochemistry. 1998 Apr 7;37(14):4782-90. PMID:9537994
Page seeded by OCA on Thu Feb 21 11:39:38 2008
