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PDBsum entry 1a13
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Mast cell degranulation
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PDB id
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1a13
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References listed in PDB file
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Key reference
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Title
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G protein-Bound conformation of mastoparan-X: heteronuclear multidimensional transferred nuclear overhauser effect analysis of peptide uniformly enriched with 13c and 15n.
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Authors
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H.Kusunoki,
K.Wakamatsu,
K.Sato,
T.Miyazawa,
T.Kohno.
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Ref.
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Biochemistry, 1998,
37,
4782-4790.
[DOI no: ]
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PubMed id
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Abstract
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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.
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