Fig 4.
Comparison of the pH stability profiles of the wild-type drkN SH3 domain (black) and mutant proteins His-7 → Ala (blue), Asp-8 → Asn (red), Arg-20 → Ala (green), and Lys-21 → Ala (orange). Values of ΔGFU were determined from peak volumes of the Uexch and Fexch states in heteronuclear single quantum coherence experiments for the wild-type and each mutant, and curves were calculated as described in Methods.