Extensive unfolding of the C-LytA choline-binding module by submicellar concentrations of sodium dodecyl sulphate.
We have investigated the stability of the choline-binding module C-LytA against sodium dodecyl sulphate (SDS)-induced unfolding at pH 7.0 and 20 degrees C. A major intermediate with an unfolded N-terminal region accumulates at around 0.75 mM SDS, whereas 2.0 mM SDS was sufficient for a complete unfolding. This might be the first report of a protein being extensively unfolded by submicellar concentrations of SDS, occurring through formation of detergent clusters on the protein surface. All transitions were reversible upon SDS complexation with beta-cyclodextrin, allowing the calculation of thermodynamic parameters. A model for the unfolding of C-LytA by SDS is presented and compared to a previous denaturation scheme by guanidine hydrochloride.
Maestro
Beatriz
B
Instituto de Biologia Molecular y Celular, Universidad Miguel Hernández, Av. Universidad, s/n 03202 Elche, Alicante, Spain.
Sanz
Jesús M
JM
D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002794:Choline / Q000378:metabolism; D002942:Circular Dichroism; D008823:Micelles; D008956:Models, Chemical; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry* / Q000378:metabolism; D011489:Protein Denaturation; D012967:Sodium Dodecyl Sulfate; D013816:Thermodynamics
D001426:Bacterial Proteins; D002352:Carrier Proteins; D008823:Micelles; D012967:Sodium Dodecyl Sulfate; D009238:N-Acetylmuramoyl-L-alanine Amidase; D002794:Choline