Premium
Dioxane contributes to the altered conformation and oligomerization state of a designed engrailed homeodomain variant
Author(s) -
Hom Geoffrey K.,
Lassila J. Kyle,
Thomas Leonard M.,
Mayo Stephen L.
Publication year - 2005
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 - 10.1110/ps.041277305
Subject(s) - engrailed , tetramer , antiparallel (mathematics) , chemistry , crystallography , circular dichroism , crystallization , helix (gastropod) , stereochemistry , homeobox , biology , biochemistry , gene , physics , ecology , gene expression , quantum mechanics , snail , magnetic field , enzyme , organic chemistry
Our goal was to compute a stable, full‐sequence design of the Drosophila melanogaster engrailed homeodomain. Thermal and chemical denaturation data indicated the design was significantly more stable than was the wild‐type protein. The data were also nearly identical to those for a similar, later full‐sequence design, which was shown by NMR to adopt the homeodomain fold: a three‐helix, globular monomer. However, a 1.65 Å crystal structure of the design described here turned out to be of a completely different fold: a four‐helix, rodlike tetramer. The crystallization conditions included ∼25% dioxane, and subsequent experiments by circular dichroism and sedimentation velocity analytical ultracentrifugation indicated that dioxane increases the helicity and oligomerization state of the designed protein. We attribute at least part of the discrepancy between the target fold and the crystal structure to the presence of a high concentration of dioxane.