biostudies-literatureBaugh LNIGMS NIH HHS5201-3https://www.ebi.ac.uk/biostudies/studies/S-EPMC5030189biostudies-literatureUnknown55(37)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 clearly 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.BiochemistryA Streptavidin Binding Site Mutation Yields an Unexpected Result: An Ionized Asp128 Residue Is Not Essential for Strong Biotin Binding.PMC5030189P41 GM103393R01 GM080214Baugh LStenkamp RELybrand TPLe Trong IStayton PSfalseA Streptavidin Binding Site Mutation Yields an Unexpected Result: An Ionized Asp128 Residue Is Not Essential for Strong Biotin Binding.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 clearly 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.2016-01-01T00:00:00Z2016 Sep2021-02-20T08:32:44Z2019-03-27T02:24:45ZS-EPMC50301892760356510.1021/acs.biochem.6b00698