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The crystal structure of the designed trimeric coiled coil coil‐V a L d : Implications for engineering crystals and supramolecular assemblies
Author(s) -
Ogihara Nancy L.,
Weiss Manfred S.,
Eisenberg David,
Degrado William F.
Publication year - 1997
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560060109
Subject(s) - coiled coil , crystallography , heptad repeat , crystal structure , chemistry , leucine zipper , molecule , helix (gastropod) , supramolecular chemistry , hydrogen bond , protein structure , stereochemistry , peptide sequence , ecology , biochemistry , organic chemistry , biology , snail , gene
Abstract The three‐dimensional structure of the 29‐residue designed coiled coil having the amino acid sequence acetyl‐E VEALEKK VAALESK VQALEKK VEALEHG‐amide has been determined and refined to a crystallographic R ‐factor of 21.4% for all data from 10‐Å to 2.1‐Å resolution. This molecule is called coil‐V a L d because it contains valine in the a heptad positions and leucine in the d heptad positions. In the trigonal crystal, three molecules, related by a crystallographic threefold axis, form a parallel three‐helix bundle. The bundles are stacked head‐to‐tail to form a continuous coiled coil along the c ‐direction of the crystal. The contacts among the three helices within the coiled coil are mainly hydrophobic: four layers of valine residues alternate with four layers of leucine residues to form the core of the bundle. In contrast, mostly hydrophilic contacts mediate the interaction between trimers: here a total of two direct protein‐protein hydrogen bonds are found. Based on the structure, we propose a scheme for designing crystals of peptides containing continuous two‐, three‐, and four‐stranded coiled coils.