Anionic branched surfactants as alternative denaturing agents for protein separations.
Denaturation of a group of model proteins of diverse size and composition with three branched alkyl surfactants-sodium 2-ethylhexyl sulfate (2-EHS), sodium 3,7-dimethyloctyl sulfate (3,7-DMOS), and sodium 2-butyloctyl sulfate (2-BOS)-has been investigated using circular dichroism (CD), small-angle X-ray scattering, and polyacrylamide gel electrophoresis (PAGE). Circular dichroism reveals that 2-BOS disrupts to a higher extent the secondary structure for most of the proteins. Also, it is found that upon adsorption the shape of the protein-surfactant complexes varies from "pearl necklace" to ellipsoidal depending on the surfactant that is used. Macroscopic separations also reveal that branching sodium alkyl sulfates with n-butyl (2-BOS) and n-methyl (3,7-DMOS) groups significantly affects their performance in PAGE. 3,7-DMOS and 2-BOS result in anomalous migrations that deviate from the expected electrophoretic mobility. A combined interpretation of spectroscopy, scattering, and polyacrylamide gel electrophoresis suggests that 2-BOS promotes stronger modification of proteins during denaturation. The findings in this work aim to improve protein electrophoretic separations and the design of novel surfactants.
Chemical Engineering Department, University of Washington , Seattle, Washington 98195, United States.
Mónica
M
Ospinal-Jiménez
Danilo C
DC
Pozzo
D000838:Anions; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D008958:Models, Molecular; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*
D000838:Anions; D011506:Proteins; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate