title: 2,2,2-Trifluoroethanol-Induced structural change of peanut agglutinin at different pH: A comparative account.
abstract: Peanut Agglutinin (PNA) is a legume lectin with a unique open quarternary structure. It is a homotetrameric protein, the monomeric subunit of which is made up of 3 beta sheets. The structural change in this protein has been induced by 2,2,2-trifluoroethanol (TFE) at two different pH. At neutral pH, PNA exists as a homotetramer, while at pH 2.5, it is known to dissociate to a dimer. The effect of TFE has been studied at both the pH by intrinsic tryptophan fluorescence, far and near UV Circular Dichroism, ANS binding and dynamic light scattering. At low pH, 15% TFE is found to induce a molten globule like state that shows maximum ANS binding. Increasing concentration of TFE increases alpha helical content and the compactness of the protein. The compact PNA at higher concentration of TFE is structurally different from the native structure. The effect of TFE at neutral pH on PNA is somewhat different from that observed at low pH. TFE does not induce molten globule like state at this pH. The detailed study of the structural change of PNA by TFE has been presented.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
authors.forename: Sagarika
authors.initials: S
authors.lastname: Dev
authors.forename: R H
authors.initials: RH
authors.lastname: Khan
authors.forename: Avadhesha
authors.initials: A
authors.lastname: Surolia
mesh_terms: D000178:Acrylamides / Q000494:pharmacology; D000817:Anilino Naphthalenesulfonates / Q000378:metabolism; D002942:Circular Dichroism; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes / Q000378:metabolism; D005470:Fluorometry; D006863:Hydrogen-Ion Concentration; D008027:Light; D019887:Peanut Agglutinin / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D017510:Protein Folding; D017433:Protein Structure, Secondary / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D014270:Trifluoroethanol / Q000494:pharmacology*
chemical_list: D000178:Acrylamides; D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D019887:Peanut Agglutinin; D014270:Trifluoroethanol