1f4m
From Proteopedia
(New page: 200px<br /><applet load="1f4m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1f4m, resolution 2.25Å" /> '''P3(2) CRYSTAL STRUCT...) |
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| - | [[Image:1f4m.jpg|left|200px]]<br /><applet load="1f4m" size=" | + | [[Image:1f4m.jpg|left|200px]]<br /><applet load="1f4m" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1f4m, resolution 2.25Å" /> | caption="1f4m, resolution 2.25Å" /> | ||
'''P3(2) CRYSTAL STRUCTURE OF ALA2ILE2-6, A VERSION OF ROP WITH A REPACKED HYDROPHOBIC CORE AND A NEW FOLD.'''<br /> | '''P3(2) CRYSTAL STRUCTURE OF ALA2ILE2-6, A VERSION OF ROP WITH A REPACKED HYDROPHOBIC CORE AND A NEW FOLD.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Rop is an RNA binding, dimeric, four-helix bundle protein with | + | BACKGROUND: Rop is an RNA binding, dimeric, four-helix bundle protein with a well-defined, regular hydrophobic core ideally suited for redesign studies. A family of Rop variants in which the hydrophobic core was systematically redesigned has previously been created and characterized. RESULTS: We present a structural and thermodynamic analysis of Ala2Ile2-6, a variant of Rop with an extensively redesigned hydrophobic core. The structure of Ala2Ile2-6 reveals a completely new fold formed by a conformational "flip" of the two protomers around the dimeric interface. The free-energy profile of Ala2Ile2-6 is also very different from that of wild-type Rop. Ala2Ile2-6 has a higher melting temperature than Rop, but undergoes a slightly smaller free-energy change on unfolding. CONCLUSIONS: The structure of Ala2Ile2-6, along with molecular modeling results, demonstrate the importance of tight packing of core residues and the adoption of favorable core side chain rotamer values in determining helix-helix interactions in the four-helix bundle fold. Structural disorder at the N and C termini of Ala2Ile2-6 provides a basis for the large differences in the enthalpy and entropy of Ala2Ile2-6 folding compared with wildtype Rop. |
==About this Structure== | ==About this Structure== | ||
| - | 1F4M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1F4M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F4M OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Bishop, B.]] | [[Category: Bishop, B.]] | ||
| - | [[Category: Brunger, A | + | [[Category: Brunger, A T.]] |
[[Category: Regan, L.]] | [[Category: Regan, L.]] | ||
| - | [[Category: Willis, M | + | [[Category: Willis, M A.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: dimer]] | [[Category: dimer]] | ||
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[[Category: transcription regulation]] | [[Category: transcription regulation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:34:46 2008'' |
Revision as of 10:34, 21 February 2008
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P3(2) CRYSTAL STRUCTURE OF ALA2ILE2-6, A VERSION OF ROP WITH A REPACKED HYDROPHOBIC CORE AND A NEW FOLD.
Overview
BACKGROUND: Rop is an RNA binding, dimeric, four-helix bundle protein with a well-defined, regular hydrophobic core ideally suited for redesign studies. A family of Rop variants in which the hydrophobic core was systematically redesigned has previously been created and characterized. RESULTS: We present a structural and thermodynamic analysis of Ala2Ile2-6, a variant of Rop with an extensively redesigned hydrophobic core. The structure of Ala2Ile2-6 reveals a completely new fold formed by a conformational "flip" of the two protomers around the dimeric interface. The free-energy profile of Ala2Ile2-6 is also very different from that of wild-type Rop. Ala2Ile2-6 has a higher melting temperature than Rop, but undergoes a slightly smaller free-energy change on unfolding. CONCLUSIONS: The structure of Ala2Ile2-6, along with molecular modeling results, demonstrate the importance of tight packing of core residues and the adoption of favorable core side chain rotamer values in determining helix-helix interactions in the four-helix bundle fold. Structural disorder at the N and C termini of Ala2Ile2-6 provides a basis for the large differences in the enthalpy and entropy of Ala2Ile2-6 folding compared with wildtype Rop.
About this Structure
1F4M is a Single protein structure of sequence from Escherichia coli with as ligand. Full crystallographic information is available from OCA.
Reference
Dramatic structural and thermodynamic consequences of repacking a protein's hydrophobic core., Willis MA, Bishop B, Regan L, Brunger AT, Structure. 2000 Dec 15;8(12):1319-28. PMID:11188696
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