Vitamin-D-binding protein and gelsolin formed tight complexes with actin (Kd ~10 nm), with the DBP-actin complex forming preferentially when both were added simultaneously to G-actin.
This basic science study elucidates the individual and competitive interactions of serum vitamin-D-binding protein and plasma gelsolin with actin in solution.
Effect estimate: Kd ~10 nm
The interaction of serum vitamin-D-binding protein (DBP) and plasma gelsolin with actin was studied using fluorescent 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole-actin or N-pyrenylcarboxyamidomethyl-actin. DBP and gelsolin formed very tight complexes with one or two monomeric actin subunits respectively. Kd values of about 10 nm have been found for both complexes. When DBP and gelsolin were added simultaneously to G-actin no ternary complex was observed and the DBP-actin complex was formed preferentially. In the presence of CaCl2 no transfer of actin occurred from the 1:2 gelsolin:actin molar complex to free DBP while in the presence of EGTA one actin monomer could be transferred. DBP did not affect the severing activity of gelsolin. The effects of a mixture of gelsolin and DBP on F-actin suggest that only individual interactions of these two plasma proteins with actin occurred in solution.
Coué et al. (Wed,) reported a other. Vitamin-D-binding protein (DBP) and plasma gelsolin was evaluated on Interaction with actin (Kd ~10 nm). Vitamin-D-binding protein and gelsolin formed tight complexes with actin (Kd ~10 nm), with the DBP-actin complex forming preferentially when both were added simultaneously to G-actin.
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