A Streptavidin Binding Site Mutation Yields an Unexpected Result: An Ionized Asp128 Residue Is Not Essential for Strong Biotin Binding

作者：Baugh Loren; Le Trong Isolde; Stayton Patrick S; Stenkamp Ronald E; Lybrand Terry P^*

来源：Biochemistry, 2016, 55(37): 5201-5203.

DOI：10.1021/acs.biochem.6b00698

We report a detailed study of a point mutation,of the crucial binding site residue, D128, in the biotin streptavidin complex. The conservative substitution, D128N, preserves the detailed structure observed for the wild-type complex but has an only minimal impact on biotin binding, even though previous experimental and computational studies suggested that a charged D128 residue was crucial for high-affinity binding. These results show cleafly that the fundamental basis for streptavidin's extremely strong biotin binding affinity is more complex than assumed and illustrate some of the challenges that may arise when analyzing extremely strong ligand protein binding interactions.

• 出版日期2016-9-20