The self-assembly of alkaline folates in isotropic water solutions, with or without added salts, has been investigated by small-angle neutron-scattering, circular-dichroism, and NMR techniques. The assembled species are chiral, cylindrical aggregates of finite length, composed of stacked tetramers; each tetramer is formed by Hoogsteen-bonded folate residues. The assembly process is more efficient in the presence of an excess of Na-I ions, leading to longer aggregates with stronger tetramer-tetramer interaction. In pure water, the rods are shorter and the tetramer-tetramer interaction weaker. Association between folates can be detected by circular-dichroism spectroscopy starting from a concentration of 6.10(-4) mol l(-1), well below the critical concentration for the formation of the cholesteric mesophase (ca. 0.5 mol l(-1)).
|Titolo:||The Self-Recognition and Self-Assembly of Folic Acid Salts in Isotropic Water Solution|
|Data di pubblicazione:||1996|
|Appare nelle tipologie:||1.1 Articolo in rivista|