2GUV

Conformational Transition between Four- and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction

Summary for 2GUV

• Entry DOI: 10.2210/pdb2guv/pdb
• Related: 1EQ7 2GUS
• Descriptor: Major outer membrane lipoprotein (2 entities in total)
• Functional Keywords: lipoprotein, protein folding, pentamer, phenylalanine-zipper, unknown function
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Lipid-anchor: P69776
• Total number of polymer chains: 5
• Total formula weight: 33921.10

Authors

Liu, J.,Zheng, Q.,Deng, Y.,Kallenbach, N.R.,Lu, M. (deposition date: 2006-05-01, release date: 2006-07-25, Last modification date: 2023-08-30)

Primary citation

Liu, J.,Zheng, Q.,Deng, Y.,Kallenbach, N.R.,Lu, M.
Conformational Transition between Four and Five-stranded Phenylalanine Zippers Determined by a Local Packing Interaction.
J.Mol.Biol., 361:168-179, 2006

PubMed Abstract: Alpha-helical coiled coils play a crucial role in mediating specific protein-protein interactions. However, the rules and mechanisms that govern helix-helix association in coiled coils remain incompletely understood. Here we have engineered a seven heptad "Phe-zipper" protein (Phe-14) with phenylalanine residues at all 14 hydrophobic a and d positions, and generated a further variant (Phe-14(M)) in which a single core Phe residue is substituted with Met. Phe-14 forms a discrete alpha-helical pentamer in aqueous solution, while Phe-14(M) folds into a tetrameric helical structure. X-ray crystal structures reveal that in both the tetramer and the pentamer the a and d side-chains interlock in a classical knobs-into-holes packing to produce parallel coiled-coil structures enclosing large tubular cavities. However, the presence of the Met residue in the apolar interface of the tetramer markedly alters its local coiled-coil conformation and superhelical geometry. Thus, short-range interactions involving the Met side-chain serve to preferentially select for tetramer formation, either by inhibiting a nucleation step essential for pentamer folding or by abrogating an intermediate required to form the pentamer. Although specific trigger sequences have not been clearly identified in dimeric coiled coils, higher-order coiled coils, as well as other oligomeric multi-protein complexes, may require such sequences to nucleate and direct their assembly.

PubMed: 16828114
DOI: 10.1016/j.jmb.2006.05.063

Experimental method

X-RAY DIFFRACTION (1.4 Å)