This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1p9i
From Proteopedia
(New page: 200px<br /><applet load="1p9i" size="450" color="white" frame="true" align="right" spinBox="true" caption="1p9i, resolution 1.17Å" /> '''Coiled-coil X-ray st...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1p9i.jpg|left|200px]]<br /><applet load="1p9i" size=" | + | [[Image:1p9i.jpg|left|200px]]<br /><applet load="1p9i" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1p9i, resolution 1.17Å" /> | caption="1p9i, resolution 1.17Å" /> | ||
'''Coiled-coil X-ray structure at 1.17 A resolution'''<br /> | '''Coiled-coil X-ray structure at 1.17 A resolution'''<br /> | ||
==Overview== | ==Overview== | ||
| - | We determined the 1.17 A resolution X-ray crystal structure of a hybrid | + | We determined the 1.17 A resolution X-ray crystal structure of a hybrid peptide based on sequences from coiled-coil regions of the proteins GCN4 and cortexillin I. The peptide forms a parallel homodimeric coiled-coil, with C(alpha) backbone geometry similar to GCN4 (rmsd value 0.71 A). Three stabilizing interactions have been identified: a unique hydrogen bonding-electrostatic network not previously observed in coiled-coils, and two other hydrophobic interactions involving leucine residues at positions e and g from both g-a' and d-e' interchain interactions with the hydrophobic core. This is also the first report of the quantitative significance of these interactions. The GCN4/cortexillin hybrid surprisingly has two interchain Glu-Lys' ion pairs that form a hydrogen bonding network with the Asn residues in the core. This network, which was not observed for the reversed Lys-Glu' pair in GCN4, increases the combined stability contribution of each Glu-Lys' salt bridge across the central Asn15-Asn15' core to approximately 0.7 kcal/mole, compared to approximately 0.4 kcal mole(-1) from a Glu-Lys' salt bridge on its own. In addition to electrostatic and hydrogen bonding stabilization of the coiled-coil, individual leucine residues at positions e and g in the hybrid peptide also contribute to stability by 0.7 kcal/mole relative to alanine. These interactions are of critical importance to understanding the stability requirements for coiled-coil folding and in modulating the stability of de novo designed macromolecules containing this motif. |
==About this Structure== | ==About this Structure== | ||
| - | 1P9I is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | + | 1P9I is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1P9I OCA]. |
==Reference== | ==Reference== | ||
| Line 15: | Line 15: | ||
[[Category: coiled-coil]] | [[Category: coiled-coil]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:26:36 2008'' |
Revision as of 12:26, 21 February 2008
|
Coiled-coil X-ray structure at 1.17 A resolution
Overview
We determined the 1.17 A resolution X-ray crystal structure of a hybrid peptide based on sequences from coiled-coil regions of the proteins GCN4 and cortexillin I. The peptide forms a parallel homodimeric coiled-coil, with C(alpha) backbone geometry similar to GCN4 (rmsd value 0.71 A). Three stabilizing interactions have been identified: a unique hydrogen bonding-electrostatic network not previously observed in coiled-coils, and two other hydrophobic interactions involving leucine residues at positions e and g from both g-a' and d-e' interchain interactions with the hydrophobic core. This is also the first report of the quantitative significance of these interactions. The GCN4/cortexillin hybrid surprisingly has two interchain Glu-Lys' ion pairs that form a hydrogen bonding network with the Asn residues in the core. This network, which was not observed for the reversed Lys-Glu' pair in GCN4, increases the combined stability contribution of each Glu-Lys' salt bridge across the central Asn15-Asn15' core to approximately 0.7 kcal/mole, compared to approximately 0.4 kcal mole(-1) from a Glu-Lys' salt bridge on its own. In addition to electrostatic and hydrogen bonding stabilization of the coiled-coil, individual leucine residues at positions e and g in the hybrid peptide also contribute to stability by 0.7 kcal/mole relative to alanine. These interactions are of critical importance to understanding the stability requirements for coiled-coil folding and in modulating the stability of de novo designed macromolecules containing this motif.
About this Structure
1P9I is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Unique stabilizing interactions identified in the two-stranded alpha-helical coiled-coil: crystal structure of a cortexillin I/GCN4 hybrid coiled-coil peptide., Lee DL, Ivaninskii S, Burkhard P, Hodges RS, Protein Sci. 2003 Jul;12(7):1395-405. PMID:12824486
Page seeded by OCA on Thu Feb 21 14:26:36 2008
