title: Structure and stability of Ricinus communis haemagglutinin.
abstract: The molecular properties of the haemagglutinin of Ricinus communis (RCA I or RCA 120) were evaluated by analytical ultracentrifugation, light-scattering, c.d. and fluorescence. The native molecule had a fairly expanded structure (f/f0 = 1.43) and dissociated into two subunits of equal size in 6 M-guanidinium chloride. This native structure was stable in alkali (up to pH 11) and resistant to thermal denaturation at neutrality. A pH-triggered change in the haemagglutinin conformation was observed and characterized by analytical ultracentrifugation, c.d. and fluorescence between pH 7 and 4.5, the range in which its affinity for galactosides decreased [Yamasaki, Absar & Funatsu (1985) Biochim, Biophys. Acta 828, 155-161]. These results are discussed in relation to those reported in the literature for other lectins and more especially ricin, for which a pH-dependent conformation transition has been observed in the same range of low pH.
mesh_terms: D002367:Ricinus communis / Q000032:analysis*; D002942:Circular Dichroism; D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D037102:Lectins; D037121:Plant Lectins; D010947:Plants, Toxic; D012278:Ricinus / Q000032:analysis*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D014461:Ultracentrifugation
chemical_list: D037102:Lectins; D037121:Plant Lectins; C017707:Ricinus communis agglutinin-1