1KFM

Core side-chain packing and backbone conformation in Lpp-56 coiled-coil mutants

Summary for 1KFM

• Entry DOI: 10.2210/pdb1kfm/pdb
• Related: 1EQ7 1JCB 1KFN
• Descriptor: MAJOR OUTER MEMBRANE LIPOPROTEIN (2 entities in total)
• Functional Keywords: lipoprotein, protein folding, helix capping, alanine-zipper, membrane protein
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Lipid-anchor: P69776
• Total number of polymer chains: 1
• Total formula weight: 6073.55

Authors

Liu, J.,Cao, W.,Lu, M. (deposition date: 2001-11-21, release date: 2002-06-28, Last modification date: 2023-08-16)

Primary citation

Liu, J.,Cao, W.,Lu, M.
Core side-chain packing and backbone conformation in Lpp-56 coiled-coil mutants.
J.Mol.Biol., 318:877-888, 2002

PubMed Abstract: 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.

PubMed: 12054830
DOI: 10.1016/S0022-2836(02)00138-9

Experimental method

X-RAY DIFFRACTION (2 Å)