1kfn
From Proteopedia
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Core side-chain packing and backbone conformation in Lpp-56 coiled-coil mutants
Overview
Native proteins exhibit precise geometric packing of atoms in their, hydrophobic interiors. Nonetheless, controversy remains about the role of, core side-chain packing in specifying and stabilizing the folded, structures of proteins. Here we investigate the role of core packing in, determining the conformation and stability of the Lpp-56 trimerization, domain. The X-ray crystal structures of Lpp-56 mutants with alanine, substitutions at two and four interior core positions reveal trimeric, coiled coils in which the twist of individual helices and the helix-helix, spacing vary significantly to achieve the most favored superhelical, packing arrangement. Introduction of each alanine "layer" into the, hydrophobic core destabilizes the superhelix by 1.4 kcal mol(-1). Although, the methyl groups of the alanine residues pack at their optimum van der, Waals contacts in the coiled-coil trimer, they provide a smaller component, of hydrophobic interactions than bulky hydrophobic side-chains to the, thermodynamic stability. Thus, specific side-chain packing in the, hydrophobic core of coiled coils are important determinants of protein, main-chain conformation and stability.
About this Structure
1KFN is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Core side-chain packing and backbone conformation in Lpp-56 coiled-coil mutants., Liu J, Cao W, Lu M, J Mol Biol. 2002 May 3;318(3):877-88. PMID:12054830
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