1f4m
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(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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Revision as of 12:29, 20 November 2007
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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 CA 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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