Open AccessBeyond the detergent effect: a binding site for sodium dodecyl sulfate (SDS) in mammalian apoferritin
Author(s) -
Liu Renyu,
Bu Weiming,
Xi Jin,
Mortazavi Shirin R.,
CheungLau Jasmina C.,
Dmochowski Ivan J.,
Loll Patrick J.
Publication year - 2012
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s0907444912002740
Subject(s) - sodium dodecyl sulfate , isothermal titration calorimetry , chemistry , dissociation constant , crystallography , pulmonary surfactant , biophysics , biochemistry , biology , receptor
Although sodium dodecyl sulfate (SDS) is widely used as an anionic detergent, it can also exert specific pharmacological effects that are independent of the surfactant properties of the molecule. However, structural details of how proteins recognize SDS are scarce. Here, it is demonstrated that SDS binds specifically to a naturally occurring four‐helix bundle protein: horse apoferritin. The X‐ray crystal structure of the apoferritin–SDS complex was determined at a resolution of 1.9 Å and revealed that the SDS binds in an internal cavity that has previously been shown to recognize various general anesthetics. A dissociation constant of 24 ± 9 µ M at 293 K was determined by isothermal titration calorimetry. SDS binds in this cavity by bending its alkyl tail into a horseshoe shape; the charged SDS head group lies in the opening of the cavity at the protein surface. This crystal structure provides insights into the protein–SDS interactions that give rise to binding and may prove useful in the design of novel SDS‐like ligands for some proteins.