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Ca‐dependent binding of actin to gelsolin
Author(s) -
Khaitlina Sofia,
Hinssen Horst
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02657-1
Subject(s) - gelsolin , actin , cleavage (geology) , chemistry , biophysics , ternary complex , actina , fluorescence , biochemistry , biology , cytoskeleton , enzyme , cell , paleontology , physics , quantum mechanics , fracture (geology)
Ca 2+ of 0.3–1.0 μM induces both the exposure of tryptic cleavage sites within the gelsolin molecule inaccessible in the Ca‐free conformation, and binding of one actin monomer to the N‐terminal half of gelsolin. On the other hand, gelsolin‐induced enhancement of pyrene actin fluorescence was observed only above 50 μM Ca 2+ , and a ternary actin/gelsolin complex preformed in 200 μM Ca 2+ was stable only above 30 μM Ca 2+ . These results provide direct evidence for Ca‐induced transitions from closed to open conformation of the gelsolin molecule in the range of 3×10 ‐7 to 10 −6 M Ca 2+ . They also suggest that Ca 2+ >10 −5 M is required to stabilize actin–actin contacts in the 2:1 actin/gelsolin complex.