Albumin binds self-assembling dyes as specific polymolecular ligands.
Self-assembling dyes with a structure related to Congo red (e.g. Evans blue) form polymolecular complexes with albumin. The dyes, which are lacking a self-assembling property (Trypan blue, ANS) bind as single molecules. The supramolecular character of dye ligands bound to albumin was demonstrated by indicating the complexation of dye molecules outnumbering the binding sites in albumin and by measuring the hydrodynamic radius of albumin which is growing upon complexation of self-assembling dye in contrast to dyes lacking this property. The self-assembled character of Congo red was also proved using it as a carrier introducing to albumin the intercalated nonbonding foreign compounds. Supramolecular, ordered character of the dye in the complex with albumin was also revealed by finding that self-assembling dyes become chiral upon complexation. Congo red complexation makes albumin less resistant to low pH as concluded from the facilitated N-F transition, observed in studies based on the measurement of hydrodynamic radius. This particular interference with protein stability and the specific changes in digestion resulted from binding of Congo red suggest that the self-assembled dye penetrates the central crevice of albumin.
Stopa
Barbara
B
Chair of Medical Biochemistry, Medical College, Jagiellonian University, Kopernika 7, 31-034 Kraków, Poland.
Rybarska
Janina
J
Drozd
Anna
A
Konieczny
Leszek
L
Król
Marcin
M
Lisowski
Marek
M
Piekarska
Barbara
B
Roterman
Irena
I
Spólnik
Paweł
P
Zemanek
Grzegorz
G
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002942:Circular Dichroism; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D003224:Congo Red / Q000737:chemistry / Q000378:metabolism; D005070:Evans Blue / Q000737:chemistry / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008024:Ligands; D046911:Macromolecular Substances; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D013816:Thermodynamics
D004396:Coloring Agents; D008024:Ligands; D046911:Macromolecular Substances; D012710:Serum Albumin, Bovine; D003224:Congo Red; D005070:Evans Blue