The interaction of calmodulin and polylysine as studied by 1H NMR spectroscopy and sedimentation equilibrium centrifugation.
The effects of polylysine on calmodulin were assessed using 1H NMR and sedimentation equilibrium centrifugation. Sedimentation equilibrium centrifugation measurements demonstrated that calmodulin associates with polylysine at calmodulin-polylysine molar ratios ranging from 10:1 to 2.5:1 and when polylysine is increased above the molar ratio of 1:1 a precipitate is formed. At a 1:2.5 calmodulin:polylysine molar ratio, 75% of the calmodulin precipitates from the solution and virtually no polylysine is present in the precipitate. 1H NMR studies of the aromatic region of calmodulin identified chemical shifts of three peaks at a calmodulin:polylysine molar ratio of 1:1. These studies suggest that polylysine associates with calmodulin in aqueous solution and can alter the structure of calmodulin to cause calmodulin self-aggregation.
Hardy
R W
RW
Department of Pathology, University of Alabama at Birmingham 35233.
McDonald
J M
JM
Remsen
E E
EE
d'Avignon
D A
DA
Sacks
D B
DB
D000818:Animals; D001665:Binding Sites; D001921:Brain; D002147:Calmodulin / Q000737:chemistry* / Q000302:isolation & purification; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008970:Molecular Weight; D011107:Polylysine / Q000737:chemistry* / Q000302:isolation & purification; D011485:Protein Binding; D011487:Protein Conformation; D013552:Swine; D014461:Ultracentrifugation / Q000379:methods
D002147:Calmodulin; D011107:Polylysine; D006859:Hydrogen