Open AccessInteractions of pig plasma gelsolin with G‐actin
Author(s) -
WEEDS Alan G.,
HARRIS Harriet,
GRATZER Walter,
GOOCH John
Publication year - 1986
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1986.tb10126.x
Subject(s) - gelsolin , ternary complex , egta , actin , iodoacetamide , chemistry , cooperativity , biophysics , actina , calcium , fluorescence , ternary operation , cooperative binding , biochemistry , binding site , biology , cytoskeleton , cysteine , enzyme , physics , organic chemistry , quantum mechanics , computer science , cell , programming language
Pig plasma gelsolin forms a ternary complex with monomeric actin in 0.1 mM CaCl 2 and a binary complex in EGTA (<0.01 μM calcium), as shown by gel filtration and fluorescence changes when actin which had been treated with N ‐ethylmaleimide and 7‐chloro‐4‐nitrobenzeno‐2‐oxa‐1,3‐diazole (NBD‐actin) or with N ‐(1‐pyrenyl)iodoacetamide (PI‐actin) binds to gelsolin. The fluorescence enhancement per actin molecule bound is similar in the binary and ternary complexes, but the affinity of gelsolin for labelled actin is very much greater in the presence of calcium. Furthermore, the formation of ternary complex exhibits strong positive cooperativity.