posted on 2016-02-20, 06:15authored byBryan F. Shaw, Grégory F. Schneider, George M. Whitesides
This paper describes the interaction between ubiquitin
(UBI) and
three sodium n-alkyl sulfates (SCnS) that have the same charge (Z = −1)
but different hydrophobicity (n = 10, 12, or 14). Increasing the hydrophobicity of the n-alkyl sulfate resulted in (i) an increase in the number
of distinct intermediates (that is, complexes of UBI and surfactant)
that form along the pathway of unfolding, (ii) a decrease in the minimum
concentrations of surfactant at which intermediates begin to form
(i.e., a more negative ΔGbinding of surfactant for UBI), and (iii) an increase in the number of surfactant
molecules bound to UBI in each intermediate or complex. These results
demonstrate that small changes in the hydrophobicity of a surfactant
can significantly alter the binding interactions with a folded or
unfolded cytosolic protein.