Title
Octarellin VI: Using Rosetta to Design a Putative Artificial (β/α)8 Protein
Author
Maximiliano Figueroa, Nicolas Oliveira, Annabelle Lejeune, Kristian W. Kaufmann, Brent M. Dorr, André Matagne, Joseph A. Martial, Jens Meiler, Cécile Van de Weerdt
Year
2013
Journal
PLoS ONE
Abstract
The computational protein design protocol Rosetta has been applied successfully to a wide variety of protein engineering problems. Here the aim was to test its ability to design de novo a protein adopting the TIM-barrel fold, whose formation requires about twice as many residues as in the largest proteins successfully designed de novo to date. The designed protein, Octarellin VI, contains 216 residues. Its amino acid composition is similar to that of natural TIM-barrel proteins. When produced and purified, it showed a far-UV circular dichroism spectrum characteristic of folded proteins, with α-helical and β-sheet secondary structure. Its stable tertiary structure was confirmed by both tryptophan fluorescence and circular dichroism in the near UV. It proved heat stable up to 70°C. Dynamic light scattering experiments revealed a unique population of particles averaging 4 nm in diameter, in good agreement with our model. Although these data suggest the successful creation of an artificial α/β protein of more than 200 amino acids, Octarellin VI shows an apparent noncooperative chemical unfolding and low solubility.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Tertiary structure, Thermal stability, Chemical stability, Biochemistry